Wednesday, December 29, 2010

Weak current College】 【commonly used refrigerant substitution】.

Commonly used refrigerant substitution
R12 refrigerant has. R22. R134a. R152a. R600a. h-01. RH. H. R404. R401. R152a and R22 mixed refrigerant. Commonly used refrigerants with R12. R22. R134a. R152a. R600a. General can R12. R22 substitution R152a. H-01. RH. H. R404.R152a and R22 of mixed refrigerant R12 substitution can be used. R404. R152a and R22 of mixed refrigerant R22 substitution can be used. R12 R22 are generally not available and each substitution. R12 refrigerants have refrigerator, R134, R600, R152/R22 azeotropic refrigerant there is air conditioning in common, there is a new type refrigerant R22 R404 refrigerator repair can be used instead of R12 substitution shall replace R134 system compressor system, mainly frozen oil differences, so be washing lines. Air conditioning repair R404 dedicated, manufacturers do not allow substitution of R22.

Weak current College】 【MCU c language tutorial-lesson one: building your first C projects】.

<br> 51 MCU C language learning Miscellanies Learn SCM is not an easy task, to purchase high price of programmer, emulator, to learn a programming language, there are many types of single-chip select is really a headache. 51 in the numerous .single-chip architecture chips popular long learning material is relatively many, is dropping one of the better choice. 51 programming language commonly used two types of Assembly language, one is the C language. The Assembly language of the machine code generated is very efficient but .readability is not strong, complex procedures is difficult to read, and the C language in most cases its machine code generation efficiency and assembly-language equivalent, but readability and portability are far more than Assembly language and C language can also be embedded into the Assembly .to address the high effectiveness of the code. For the development cycle, in large software written in c language development cycle is usually much smaller than Assembly language. The above advantages of C language, I'm learning with the C language. Later in the .tutorial also just in the learning process of some study notes and essays, tidying up and modify, hope to join the Exchange with the wing, fertilizer, learning, progress together. <br> * Note: you can say for sure that this tutorial is .for beginners or novice, I myself have just amateurs, is expected to master the pointing errors you heroes. <br> Bill Rammell 2003-3-30 first lesson establishes your first C program using C language would use to C .compiler in order to write ac program compiled to machine code, so that the SCM can perform write good programs. KEIL uVISION2 is many SCM application development software in one of the best software, it supports many different companies MCS51 chips, its schema set to edit ., compile, simulation is equal to one, while also supporting, PLM, compilation and C language programming, the interface and commonly used Microsoft VC + + interface similar to that of a friendly interface, easy to learn and use, in the debugger, software .simulation also has very powerful features. So many development 51 application engineers or ordinary single-chip microcomputer enthusiasts, but also for its 10 fertilizer. <br> The above outlined KEIL51 software, to use the software, the necessary first KEIL51 to install it. .KEIL51 is a commercial software for our ordinary fans can go to the KEIL Chinese agent ucos website, downloading can compile 2 k DEMO Edition software, the Basic can meet the General personal learning and development of small applications. (The installation methods and General software do .not quite here introduced) <br> After installation, you can hardly wait to build their first C program project? here let's set up a small project. Perhaps your hand is not a piece of experimental Board, not even a single chip, but no .relationship we can see through the KEIL software simulation program to run. <br> First of course is run KEIL51 software. How to open? Oh! you want to learn computer from scratch. Oh, a joke, I think the readers will not mention .: P. Run for a few seconds to appear as in Figure 1-1 on the screen. <br> <br> Figure 1-1 startup screen <br> Then follow these steps to build your first item: <br> (1 .) click on the Project menu, select the drop-down menu that pops up in the New Project, as in Figure 1-2. Then bring up a standard Windows file dialog window, shown in Figure 1-3, this stuff must all be .met N times, usage tips also not here to say that subsequent chapters will no longer appear similar. In the file name box, enter your first C program project name, here we use the "test", this is the name of the author, .you don't have to copy it, as long as you comply with the file name of the Windows file rules. "Save" the file extension after uv2, KEIL uVision2 project file extension, then we can click on this file to open the items .previously done. <br> <br> Figure 1-2 New Project menu <br> <br> Figure 1-3 file window <br> (2) select the MCU that here we select common Ateml company AT89C51. The screen shown in .Figure 1-4 below. What is the function, AT89C51 features?, without hurry illustration on the right there is a simple introduction, later chapters will make more detailed introduction. After completing the above steps, we can write a program. <br> .(3) first of all we want in a project to create a new program file, or to join the old program files. If you do not have ready-made program, create a program file. Some of the KEIL program Demo, here we .are in a C program, for example describes how to create a C program and how to add to your first project. Click on Figure 1-5 in 1 of the new file shortcut buttons, 2 a new text editing window, this operation can also .be accessed from menu File-New or the shortcut CTRL + N. OK, now you can write a program, the cursor has been appearing in text edit window, waiting for our input. The first program, write a simple and straightforward. Here is .a classic, Oh, if you read another program book may have similar programs: # include <AT89X51.H> <br> # include <stdio.h> void main (void) <br> {<br> SCON = 0x50 .; / / Serial mode 1, allows to receive <br> TMOD = 0x20; / / Timer 1 timing mode 2 <br> TCON = 0x40; / / Set timer 1-countBR> TH1 = 0xE8; / / 11.0592MHz 1200 baud rate .<br> TL1 = 0xE8; <br> TI = 1; <br> TR1 = 1; / / Start the timer <br> <br> while (1) <br> {<br> printf ("Hello World! \ .n "); / / Displays Hello World <br>} <br>} <br> <br> Figure 1-4 to select the chip <br> <br> <br> Figure 1-5 new program files <br> .This program features are continuously from the serial port output "Hello World!" Characters, regardless of the program syntax and meaning, first take a look at how to integrate it into your project and how to compile the test run. <br> (4 .) click on Figure 1-5 of 3 saved new programs, or you can use menu File-Save or the shortcut CTRL + S to save it. Due to the new file saved will pop out similar to figure 1-3 file operations window, .we put the first program named test1.c, saved in the project in the same directory, then you will find that Word has a different color, description of the C syntax checking KEIL. Figure 1-6 the mouse on the left side of the .screen Source Group1 folder icon on the right click popup menu, where you can do to increase the reduction in the project file, and so on. We? quot; Add to Group 'Source File Group 1' pop-up window, select the file .just saved the file, press the ADD button, close the file Windows, program files have been added to the project. At this point in the Source folder icon to the left a Group1 a little plus sign on the instructions, a file group with the .file, click it to expand the view. <br> <br> Figure 1-6 the file to the project file group <br> (5) C program file has been added to the project, we have compiled the following left running. .This project, we just make learning a new program item and compile run simulation method, using default settings for the compilation of the software, it will not be generated for chip Programmer's HEX file, how to set the generate HEX file, please see the following .third lesson. Let's look at Figure 1-7, Figure 1, 2, 3 are compile button, different is 1 is used to compile a single file. 2 compile the current project, if a previously compiled once files are not doing dynamic editorial changes ., and then click is not recompiled again. 3 is recompiled, every click on a link will be once again compile once, regardless of whether the program has changed. In 3 right is to stop the compile button, click on the first three of the .stop button to take effect. 5 of them in the menu, I personally would not use it. Hei Hei, this project has only one file, you press a 123 can be compiled. Press the? good fast Oh, huh, huh. You .can see in the 4 compile error message and the use of system resources, etc, then we want to look up the wrong depends on it. 6 is there a small magnifying glass button that is open to close debug mode / button, it also exists .in the Debug menu, shortcut keys Debug-Start \ Stop Session as Ctrl + F5. <br> <br> Figure 1-7 compiler <br> (6) to enter debug mode, the software window styles is roughly as in Figure 1 .-8. Figure 1 is running, when the program is in a stopped state, 2 to stop, when the program is running. 3 is reset, the simulation of chip reset, the program back to the beginning of the implementation. 4 we can .open 5 serial debugging window, the window we can see from the 51 chip serial port input and output character, here's the first project is here to see the results. These are also in the menu, there is no longer a presentation you may wish to .look, and other features are also in later lessons gradually introduced. First by 4 open serial debug window, and then press the run button, then you can see the serial debug window keep playing? quot; Hello World! ". Oh, is not .difficult to? this completes your first C program. Finally we have to stop the program to run back to the file in edit mode, press the stop button and then press open / close debug mode button. And then we can hold off KEIL, and .other related operations. <br> At this point, the first lesson has ended, the preliminary study a number of project files KEIL uVision2 create, compile, run, and the basics of software simulation. Which have been mentioned in some of the features of .the use of shortcuts, indeed in the actual development of the application in the application shortcut keys can greatly improve work efficiency, it is recommended that we can use there here mentioned how by analogy to similar operations. <br> <br> Figure 1 - .8 debugging to run the program <br> This tutorial all 9 classes, please query other related 8 class, combining the last source program learning! C51 tutorial full version of matching source download. rar.

【 Weak current College 】 digital circuit how anti-jamming 】

In the design of electronic systems, in order to make detours and save time, you should take full account of and meet the requirements of the immunity, to avoid design is finished and then go to a antijamming remedies. Form the basic elements of disturbance are three:
(1) the source of interference, means produce interference components, equipment, or a signal, using a mathematical language description: du/dt and di/dt Grand place is the source of interference. For example: Thunder and lightning, relays, SCR, motor, high-frequency clock, etc can become the source of interference.
(2) propagation path means interference from sources of interference to access sensitive devices or media. Typical interference propagation path through the wires of conduction and radiation in space.
(3) sensitive devices that can easily be interference. Example: A/D and D/A Converters Microcontroller and digital ICS, weak signal amplifiers, etc. Anti-jamming design basic principle is: Suppression of interference sources, to cut off the noise propagation path, improve anti-interference performance sensitive devices. (Similar to infectious disease prevention)
1 sources of interference
Suppression of interference is possible to reduce the interference source du/dt and di/dt. This is a antijamming design of the highest priority and the most important principle, often has a multiplier effect. Reduce interference sources du/dt, mainly through the interference source to achieve parallel capacitance at both ends. Reduce the interference of the di/dt is interference source loop inductance or resistance and increase continued flow diode.
Suppression of interference sources of common measures are as follows:
(1) relay coil increase continued flow diode, eliminating broken coil of back-EMF. Only with continued flow diode will enable relay disconnect time lag, increase the Zener diode rear relay in unit time action more often.
(2) the ends of the relay contacts and add spark suppression circuit (typically RC series circuit, general elections a few K resistor to dozens of K, capacitors selected 0.01uF), decrease the EDM.
(3) to the motor and filter circuit, capacitors, inductors leads to short.
(4) the Board each IC to and received a 0.01 μ F ~ than 0 μ F high-frequency capacitors to reduce the effect of the power supply IC. Note the high-frequency capacitance of wiring, wiring should be close to the power supply side and short thick as possible, otherwise, equal to increase the capacitance of the equivalent series resistance, affect the filter effect.
(5) wiring avoid 90 ° bend, reduce the high frequency noise emission.
(6) thyristor suppression received on both sides and RC circuits, reduce the noise generated by Silicon controlled rectifier (this noise serious may be SCR breakdown). By interference propagation path can be divided into conducted interference and radiated interference.
The so-called conducted interference is defined through the wire to sensitive devices. High-frequency interference noise and useful signal frequency bands, can lead to increase filter method for cutting high-frequency interference noise transmission, sometimes can also be combined with optical coupling isolation. Power noise hazards maximum, paying special attention to the process. The so-called radiated interference is propagated through space radiation sensitive devices. The general solution is to increase the interference sources and sensitive devices distance ground their isolation and in sensitive devices on the short hood. Cut the noise propagation path of common measures are as follows:
(1) take full account of the impact of on-chip power supply. The power to do well, the entire circuit interference most of the settlement. Many of the microcontroller is sensitive to the power supply noise, to give single-chip power plus filter circuit or regulators to reduce power noise interference on the microcontroller. For example, you can use beads and capacitance constituted π-shaped filter circuit, course conditions requirements is also available in 100 Ω resistor substitute beads.
(2) if the microcontroller I/O port used to control the motor noise, and the i/o port should be added between the noise source isolation (increase the π-filter). Control motor, noise, noise in the I/O port and should be added between the source isolation (increase the π-filter).
(3) Note Crystal wiring. Crystal oscillator and a microcomputer PIN as close as possible to that ground the clock district isolation, Crystal shell grounding and fixed. This measure can solve many problems.
(4) reasonable partition, such as circuit boards, weak signal, digital and analog signals. As far as possible sources of interference (e.g. motors, relays) and sensitive components (such as SCM) away.
(5) with a ground to digital and analog DC isolation, digital and analog to detach, point final in received power. A/D and D/A chip wiring also as a principle, manufacturers assign A/D and D/A chip pin arrangement is already considering this request.
(6) MCU and high-power devices ground to separate ground to reduce interference. High-power devices in the circuit board edge as possible.
(7) on-chip I/O port, power cables, printed circuit board connectors, and other key parts of the anti-jamming components such as beads, steepness, power filter, shielding enclosures, can significantly improve the performance of the circuit. 3 improve anti-interference performance sensitive devices
Improve anti-interference performance sensitive devices is measured from the sensitive devices here consider minimizing interference noise pickup, and never a normal status as soon as possible.
Improve sensitive devices anti-interference performance of common measures are as follows:
(1) wiring to minimize the loop area, central to reduce induced noise.
(2) wiring, power and ground to rough. In addition to reduce pressure drop, and more importantly reduce coupling noise.
(3) in the case of single-chip I/O port are idle, not vacant, to ground or power supply. Other IC free-without altering the system logic ground or power supply.
(4) on-chip power monitoring and watchdog circuit, such as: IMP809, IMP706, IMP813, X25043, X25045, can greatly improve the performance of the entire circuit.
(5) in speed to meet the requirements, minimize the use of Crystal andLow-speed digital circuits.
(6) IC devices try to direct welding at the Board, the use of IC socket.

【 Weak current College 】 humidity technology, the use of humidity approaches 】

The basic concept of humidity measurement in industrial and agricultural production, meteorology, environmental protection, defense, research, and aerospace sectors, often need to ambient humidity measurement and control. On the environmental temperature and humidity control, as well as industrial material moisture value of monitoring and analysis have become more common technical specifications, but in general the environmental parameters, humidity is the most difficult to accurately measure of a parameter. This is because the measurement of humidity than the much more complex measuring temperature, temperature is a measure of independence, and the humidity is affected by other factors (atmospheric pressure, temperature). In addition, humidity calibration is also a challenge. Overseas production of humidity calibration equipment prices are expensive. First, the definition in the measurement of humidity in the law, the humidity is defined as "an image of the State". Daily life within the meaning of the humidity as relative humidity, RH% said. In short, the gases (typically air) containing a quantity of steam (water vapour pressure) and air the same circumstances the amount of saturated steam (saturated vapor pressure).
Humidity long ago and life there is a close relationship, but the number used to represent the more difficult. Representation on humidity absolute humidity, relative humidity, dew point, moisture and dry gas ratio (weight or volume), and so on. Second, the humidity measurement humidity measurement Division from principle has 20 or 30. But the humidity measurement is always the world metrology area one of the well-known problem. A seemingly simple measure, deep dive, involve very complex physical-chemical analysis and calculations, the new entrants may be ignored in the humidity measurement is essential to note that many factors affect the sensor of fair use. Common humidity measurement methods are: dynamic method (dual-pressure method, dual temperature method, method), static (saturated salt method, sulfuric acid method), dew point, wet and dry bulb and electronic sensors. ① double pressure method, dual temperature method is based on thermodynamic P, V, T balance theory, balance time, streaming method is based on the absolute humidity and absolutely dry air of the precise mix. Thanks to modern measurement and control instruments, these devices can be pretty accurate, but because of equipment complex, expensive, time-consuming and requires a major operation, as a standard measurement, the measurement accuracy of up to ± 2% RH. ②-static method in the saturated salt method, is the humidity in the measurement of the most common way is easy. But saturated salt method for liquid, gas two-phase balance requires very strict environmental temperature stability requirements. Use request wait a long time to balance, low moisture demands an even longer. Particularly in indoor humidity and bottles humidity difference is large, each time you open the need to balance 6 ~ 8 hours. ③ dew point method is the measurement of moist air becomes saturated when thermodynamic temperature, is the direct result of the measurement accuracy is high, wide range. Measurement of dew-point hygrometer with precision accuracy up to ±0 0.2 ° c or even higher. But with the modern theory of optical-electronic hygrometer is expensive, often and standard humidity generator use. ④ wet and dry bulb method, which is 18 century invention of moisture. A long history, the most commonly used. Wet and dry bulb method is an indirect method, which uses psychrometric humidity value conversion out of the equation, the equation is conditional: that is, in the wet-bulb nearby wind speed required to achieve 2.5m/s or more. General use of wet and dry bulb thermometers simplifies this condition, so its accuracy only 5 ~ 7% RH, wet and dry bulb does not belong to a static method, not to simply think that raising two thermometers measuring accuracy is to improvethe accuracy of the measuring Chamber. Dry and wet bulb measurement using the wet method, the indirect measuring methods by measuring the dry bulb and wet bulb temperature after the calculated humidity value. Therefore, there is no strict restrictions on the use of temperature, high temperature measuring humidity will not cause damage to the sensor. Wet and dry bulb hygrometer's features:
As early as the 18th century man invented the wet and dry bulb hygrometer, wet and dry bulb hygrometer accuracy depends on the dry bulb and wet bulb thermometer itself of two precision; hygrometer must be ventilated State: only the gauze jacket, water, wind speed will meet certain requirements in order to achieve the required accuracy. Wet and dry bulb hygrometer accuracy only 5 per cent of a 7% RH. ⑤ electronic humidity sensor method electronic humidity sensor products and humidity measurement is the rise of industry in the 90s, in recent years, both at home and abroad in the field of humidity sensor research and development has made tremendous progress. Humidity sensors are simple humidity sensor to integrated, intelligent, multi-parameter detection of direction of rapid development, to develop a new generation of humidity measurement and control system for creating favorable conditions to humidity measurement technology to the next level. Third, the humidity measurement programmes to choose the most modern humidity measurement programmes mainly in two ways: wet and dry bulb and wet measurement, electronic humidity sensor wet. Following these two programmes, so that the customer chooses the suitable humidity measurement method. Wet and dry bulb measuring wet maintenance is simple, in actual use, you only need to regularly add water to wet-bulb and wet bulb gauze can be replaced. Compared with electronic humidity sensor, wet and dry bulb moisture method does not generate a ageing, precision decline. So wet and dry bulb moisture method is more suitable for high temperature and harsh environments. Electronic humidity sensor characteristics: and electronic humidity sensor is in recent decades, especially in the last 20 years to develops rapidly. Humidity sensor production plant in products manufactured before the adoption of standard humidity generator to calibration-by-team, electronic humidity sensor accuracy can reach a 3% 2% RH. In actual use, due to dust, oil and harmful gases, use over time, will produce a decline in ageing, precision, humidity sensor, the excursion is generally in ± 2% or even higher. Under normal circumstances, the manufacturer may indicate a 1 time calibration of efficient use of time for 1 year or 2 years due to calibration again. Electronic humidity sensor accuracy level in conjunction with its long-term stability to judge, generally speaking, the electronic humidity sensor for long term stability and useful life than psychrometric humidity sensor. Humidity sensor is used in semiconductor technology, the use of ambient temperature is required, more than its working temperature will cause damage to the sensor. So electronic humidity sensor wet method is more suitable in the cleansing and use at ambient temperature. 4. humidity sensor selection considerations ①. choose measuring range and measuring weight, temperature, select humidity sensor first determine the measurement range. In addition to meteorology, scientific research departments, temperature,Humidity measurement and control in General does not require all wet range (0-100% RH) measurement. ②, select measurement accuracy
The humidity sensor for measuring accuracy is the most important indicators, improving-percentage of humidity sensor is the next level, or even previous grades. Because you want to achieve different accuracy, their manufacturing costs vary greatly, prices are also very different. Therefore, users must be tailored to be blind pursuit of "high-precision, advanced".
As at different temperatures using humidity sensor, the indication should also consider the effect of temperature drift. We all know, the relative humidity is a function of temperature, temperature severely affects the relative humidity within a specified space. Temperature change 0.1 ℃. Will produce 0.5% RH of humidity change (error). Use the occasion if difficult constant temperature is raised too high moisture accuracy is not appropriate. In most cases, if there is no precise means of temperature control, or the measured space is a non-sealed, ± 5% RH precision is sufficient. For precise control of temperature and humidity in the local space, or you need to keep track of humidity changes, and then choose ±1% RH above precision humidity sensor. The precision is greater than ± 2% RH requirements even calibrate sensor standard humidity generator also difficult, not to mention the sensor itself. Relative humidity measuring instruments, even in 20-25 ° c, to reach 2% RH accuracy remains very difficult. Usually given in the product information of the characteristics is at room temperature (20 ° c ± 10 ° c) and clean gas measurement. ③, consider drift and drift
In actual use, due to dust, oil and harmful gases, use over time, electronic humidity sensor that produces an aging, precision, electronic humidity sensing device, the excursion is generally in ± 2% or even higher. Under normal circumstances, the manufacturer may indicate a 1 time calibration of efficient use of time for 1 year or 2 years due to calibration again. ④, other considerations for humidity sensors are sealed, for the protection of the measurement accuracy and stability, you should avoid in acidic, alkaline and containing organic solvents used in the atmosphere. Also avoid the dust in the larger environment. To correctly reflect the desire of humidity measurement space, you should also avoid the sensor placed too close to the walls or poorly ventilated corners. If the test room is too large, you should place more than one sensor. Some humidity sensor power supply power supply requirements is relatively high, otherwise will have an impact on measurement accuracy. Or sensor mutual interference, even not work. Should be used in accordance with the technical requirements for the provision of appropriate, consistent with the accuracy requirements of power supply.
The sensor requires long-distance signal transmission, it is necessary to pay attention to the problem of signal attenuation. When the transmission distance of more than 200m above, it is proposed to adopt frequency output signal of the humidity sensor.

【 Weak current College 】 led display system theory and engineering 】

(1) use of imported high-quality LED full colour display for chip production: a perspective on the big, small power consumption, color uniform, panel thickness thin and the screen light weight, high reliability, easy maintenance, etc.
(2) use of PCTV card: this card is a high-performance set display, capture, video capture capabilities of multimedia display card, the card accompanied by a Studio editing software. Studio is a Pinnacle Systems company's award-winning software, it with the existing universal ordinary multimedia card compare it with the following advantages:
① enabling users to your own PC making a digital movie, capture video, edit, and add the style of the title, conversion, and even your own musical and narrative in digital video production.
② S t u d I o can let the user choose to MPEG or AVI file format output video and save to CD disc, or displayed on the Web site, or create a video email. Because the Studio can and Pinnacle Systems Company of a series of capture devices, video capture is not easy before.
③ S t u d I o application software like a VCR from easy to use with good, better, best quality forms and calculate how much video can be stored on computer. Studio automatically find and record the scene change, make editing changes easily.
④ use Studio to author is a fast and interactive process. Use the instant preview window you can edit at any time in the preview of the film, see is what you get.
⑤ If you don't like a title or effect, may make a change and you can immediately see the change, video editing has never been like this fast and fun. Free, personalized enough is enough, but also has background music, voiceover, and more. (3) uses the latest technology: DVI interface DVI interface (Digital Visual Interface) is a PC and digital flat panel monitor (including) interface of industry standards, as we all know, is a digital, i.e. it deals with information on all digital, but so far the most widely used CRT monitor(such as TV sets) is analogue. Therefore the computer processing of data sent to the monitor display, you must be a d/a conversion (D/A), this process has resulted in the loss of information and displays the result of a defect. HDTV LCD, PDP, etc, a new generation of the monitor itself is digital, using traditional methods, computer graphics card output (analog) but also through the ADC (A/D) to be sent to the monitor, which in turn caused new loss and trouble. Using DVI interface, the development of LED display system directly from the PC DVI connector fetch, you do not need Galaxy card such as a dedicated video card or a special card to the PC machine, in the absence of D/A and MD conversion process, to avoid the loss of image detail, thereby ensuring the computer image in the display of a perfect reproduction. At the same time as the DVI is an industry standard although bandwidth of up to 83MHZ, also work well. Now with support for DVI VGA (640 × 480) to HDTV (1920 × 1080) and QXGA (2048 × 1536) of all display modes. In addition to a DVI connector, the development of LED display system, in a stable and reliable display data, you can set many important features integrated together, for example: ① ② without data loss, do not be PC, ③ easy upgrades, General display card memory to the memory card, but 8M to 128-256M, ④ window position and size adjustments; ⑤ frame rate as high as $ 60HZ; ⑥ nonlinear adjust output, better suited to the human eye watch; ⑦ 100 level screen brightness control; ⑧ constant current driver; ⑨ cell plate red, green, and blue brightness separately adjustable, elimination of mosaic. (4) use of the indoor full color system: this chip to display the data in addition to the completion of assigned tasks, its characteristic is to receive 8-bit (8 bit) display data converted to 12-bit PWM output pulse, so that the display screen for 4096 (12bit)-level grayscale, control, assurance of nonlinear 256-level grayscale, vision reaches full-color visuals,able to fundamentally resolve the digital display system because the amount of data transferred is too large and complex systems. Has the following characteristics:
① simplicity as the system is the most complex data conversion part to chip implements internal logic so that the system becomes very simple.
② serviceability and simplicity is directly related to the system for easy maintenance, eliminating the complex control section, system maintenance became a junior technical staff can complete the work, both to reduce overall maintenance costs, and improve user satisfaction.
③ high reliability system control part of simple further brings the system's high reliability, and this is mainly due to the integrated chip technology compared to separator technology has several times of stability.
④ cost-effective system with the most reliable performance screen color 4096 shades of control, the image displays a vivid, natural, achieving the same display control effect.
⑤ UCSD, structured design and development direction of the current industry, large screen display system screen body structure using cell-based design, system wiring of intuitive and easy to not only ensure the display of size can be adjusted according to need stitching, and makes the system installation, commissioning and maintenance become extremely simple, so as to minimize the display system's invisible failure rate.
⑥ industrialization reliability design system adopts unit design, replaced the traditional design of a large number of separator parts so that the system's reliability and stability increases.
⑦ full programmes system contains the data source, transport, equipment, data processing, data distribution and software management tools that enable the construction of the LED display screen into a simple standardized. The technology in practical application process is constantly developing and perfecting, has become a most mature, stable, easy to implement system programme.
>⑧ equivalent CRT display led display most core performance indicators for each primary color (red, green, blue) implements the brightness levels of gray, the display of the current international standard is to require every base reached 256-level gradation of vision. Special grayscale control chip built-in processing logic can output reached 4096-level grayscale, and select and CRT monitor phase fitting 256-level gradation of output, so that the overall image effects more clear, lifelike, contagious.
⑨ high resolution and high refresh rate in addition to the levels of gray, the display of the other two performance indicators is the resolution and refresh rate. Thanks to led display itself features and requirements, the traditional solution is often to lose one or two criteria as another indicator of increased price. As a result of chip each pin per second data output reaches 1 trillion, far more than the traditional scheme of data export capabilities, thereby making the problem fundamentally. This full-color systems can also support 1024 × 768 screen resolution and up to 300Hz screen refresh rate, far more than the traditional solution of performance indicators that display a stable, flicker-free, non-smearing. (5) use of constant current driver: the circuit technology is mature, reliable operation is already in full color on a wide range of use, high performance price ratio, as at present companies commonly used constant current driver IC, better resolution LED pipe pressure drop discrete defects and of good performance, eliminating mosaic. (6) fiber-optic transmission, do not decay of fiber-optic transmission technology:
① fiber transmission frequency bandwidth, communications capacity. Fiber available bandwidth of about 1.25G, frequency bandwidth, improves scanning frequency and the refresh rate, the company design LED full color screen refresh rate ≥ 200Hz/s.
② fiber transmission loss low, the relay and long distance. The maximum distance you can reachthe relay 15000 m, increased reliability and stability.
③ fiber transmission resistance to electromagnetic interference. Fiber is an insulator materials, it is not affected by the nature of the lightning, ionospheric changes and sunspot activity of interference or electrified railway feeders and high-voltage equipment and other industrial electrical interference.
④ fibre diameter thin, light and soft. Optical fiber core diameter is very thin, approximately 0.1mm, it has only one percent of single-tube coaxial cable; cable diameter is also very small, 8-core cable cross-section diameter approximately 10 mm instead of the standard coaxial cable for 47mm. The use of fiber make transmission system in occupies small space. Enable easy construction of wiring.
⑤ fiber transmission in addition to the above outstanding advantages, but also has strong corrosion resistance, resistance to nuclear radiation, energy consumption small advantages.

【 Weak current College 】 high-voltage circuit breakers refused to jump and refused-causes and solutions 】

Substations to load stop, power transmission, critical equipment is a high-voltage circuit breakers, also called high pressure oil switch, it is good or bad decision directly to the entire distribution system correctly, is the high-voltage supply and distribution system most prone to failure of vulnerabilities affecting high voltage circuit breaker does not work a number of factors, mainly present in human factors and the device itself factors and many other reasons, which are summarized as follows:

1, high-voltage circuit breaker does not switch on power transmission, this phenomenon is known as the high voltage circuit breaker switch to refuse this behavior with the phenomenon, in the scene of the accident occurs frequently.
2, high-voltage circuit breaker does not break brake power outage, this phenomenon is known as high-voltage circuit breakers refused to jump in the scene accident treatment, this phenomenon is widespread.
3, also affect the oil switch does normal and closing phenomena, is due to a switch, fuse, tripping fuse protection link breakage, damage control switch failure for many reasons, those reasons at the scene of accident treatment is very easy to determine and resolve, here not in detail.
How to keep it reliable and secure operation, is the substation equipment management priorities. Following the high-voltage substation circuit breaker rejection, refusal to skip the symptom, combined with practical, explain it solutions.
First, high-voltage circuit breakers refusal causes kg
1, high-voltage circuit breakers refused to close, high-voltage switch cabinet, after the overhaul of the debugging operation substation watch, high voltage circuit breaker for the first time, closing and opening operations are normal, but when the second closing time, resulting in rejection of hop phenomenon. Accident alerts are normal movement, sound and cue signals.
2, high-voltage circuit breakers refused-cause analysis, on-site check protection circuit connection are consistent with the original drawings, repair process does not appear the replacement unit and transform the wiring, which is why? check found that as long as a high-voltage circuit breakers break brake, skip it sucks merge relay TBJ stay. TBJ is in high voltage breaker by its current coil when started. Once started, TBJ normally open contact closure, signal voltage coil LD and TBJ-line ends, 220V control power plus in LD and TBJ voltage coils at both ends. LD for energy-saving lights, its equivalent resistance around 22 k Ω T B J as intermediate relay DZB-15B/220V, 0.5A type, its voltage DC coil resistance 9 k Ω. After finding information and calculated, LD voltage-156V, TBJ voltage to 64V, field test and calculate basic match, this intermediate relays of voltage standards by factory returned to not less than the rated voltage of 3%, thus causing a second closing of the phenomenon is due to the rejection-TBJ voltage coils are sufficient to maintain voltage, so cut off switch on the circuit.
3, solutions
(1) in the LD light circuit breakers series a close regular contact, when high-voltage circuit breaker, TBJ voltage winding is not flowing currents, of course, will not have to maintain voltage. When high-voltage breaker, both to monitor high voltage circuit breaker is good, but also can indicate whether they are opening.
(2) the LD wiring from line 3 to 5 lines after the TBJ action with its LD voltage winding down, but this approach in certain high-voltage circuit breakers actuator to alter its wiring within more hassle.
(3) if the high-voltage circuit breakers have no spare normally closed auxiliary contacts, TBJ voltage coil ends parallel a additional resistance R, TBJ voltage coil voltage not greater than the rated voltage of less than 30%. Calculate select resistance ZG11 — 50/600 Ω, and checking. Parallel 600 Ω resistor, LD voltage to 214V, TBJ voltage coil voltage to 5.5V.
4, two description
(1) high voltage circuit breaker tripped State, to calculate the additional resistance power 0.05W. Taking into account the direct voltage 220V during closing plus additional resistance, although switching power on time is very short, but the power can not be selected is too small, this case select 50W, can satisfy the requirements for safe operation.
(2) in the event of accidents, to calm, constant sum up the previous accident, summary, identify the most simple processing methods and procedures, the accumulation of experience, as the next of accident processing provides experiences and lessons learned.
2. high-voltage circuit breakers refused to jump analysis
1, high-voltage circuit breakers refused to jump in, on-duty officers found with a high-voltage switch cabinet exception display overload run 20 seconds, the transformer secondary switch tripping, but the distribution out of the Cabinet did not trip, with a high-voltage switch cabinet after the power failure does not display the exception. Watchkeeping personnel grounding selector will be elected outage. Other high-voltage switch cabinet, power supply correctly.
2, high-voltage circuit breakers rejection reasons, to jump on duty personnel about the accident and the detailed examination, considered to be the holder of the cause of the substation of the trip. Check the cabinets found overcurrent relays of the normally open contact GJ burned, after we all consider that this failure is caused because it up, but I and drawings and information check found is not a direct result of this cause of high-voltage circuit breakers refused, if the overcurrent relays of GJ contacts due to load big moments burning, then in burned while tripping circuit also through, constitutes the tripping of the conditions, should not be refused to jump? after the attendant the Cabinet side know this accident had prior to the trip record, because there was no pressure on the trip detail check on Cabinet tripping of a high-voltage Cabinet, strong andtransmission power. At that time did not find the Cabinet have any unusual phenomena, there is a result of overcurrent relays dark shell, with the result that the person on duty did not see and check to this point GJ contacts have already burned in and in front of transmission examination nor good inspection equipment, GJ contacts and HD loop in parallel, so when the power switch on the power indication light is on, the appearance of a wrong signal that trip circuit no short-term and failed, the next accident trip time overcurrent relays body movements, but at this point GJ contacts have already broken theOpen, you cannot leave the high voltage circuit breaker tripped and normal, causing the high-voltage circuit breakers refused to jump, a trip by accident.
3. settlement method
(1) strengthening substation watch officer of the business knowledge of learning and training, the organization staff in case studies and analysis to identify issues and gaps, and constantly corrections, gradually let watchkeeping personnel are familiar with the application of knowledge and on the exceptions and accident analysis, judgement and timely processing of capacity strengthening against accidents, accidents, such as learning and expected experience, constantly absorbing and deal with incidents of summary, mutual experience and lessons learned from the same people for accidents.
(2) on high-voltage switch cabinet to strict management, accident trip of switch cabinet not to have to figure out what the cause, the command transmission, so the personnel and equipment are not good, but also to expand the scope of the accident, the reasons for the non-normal trip of high-voltage switch cabinet outage, timely inspection and testing and debugging, to let the power distribution unit foolproof circumstances can be put into operation.
(3) to standardize the Substation site operation regulations, to the point of guide system refinement, watch each step should do, do not let the personon duty have ambiguous situation. On every step, every subtle link to do work of uniqueness, this will not only be able to guarantee the safety of personnel, and to protect the integrity of the device.
Closing remarks
This high-voltage switch cabinet retrofit does not appear after the same accidents. High voltage power supply is not conclusive evidence to that effect, from design to run to the operation in accordance with the procedures and systems to deal with the constant practice and system specification, only on the device the application of the familiar and in order to better protect the safety of persons and equipment, to a more rational and effective use of equipment in order to guarantee the normal power supply transformer substation safety.

【 Weak current College 】 electrostatic discharge (ESD) control of the five principles 】

Although the technical, technological and material in this period evolve, effective electrostatic discharge (ESD, electrostatic discharge) control program design and implementation is still based on the following four concepts:
· The electrostatic protection design within the components and products
· Eliminate anti-static materials and processes
· To disperse or and electrostatic discharge
· Provide on the physical protection of electrostatic discharge
Nevertheless, we often encounter problems, we should consider adding a fifth concept: to test your process and the environment. Our first concept is that design your components, products, and the Assembly, make it more reasonable to avoid electrostatic discharge (ESD). If possible, the use of electrostatic sensitive components, or on your use of the electrostatic discharge-sensitive (ESDS, ESD-sensitive) components provide the appropriate input protection. There is conflicting, advanced production technology means more compact and more complex geometry, usually more sensitive to ESD. However, in the product design to establish more ESD control, then the problem will occur.
Obviously, the product design is not a complete answer. You can avoid ESD components and products, but you can reduce or eliminate the generation and electrostatic discharge. First of all we must work environment as much as possible to reduce or eliminate many static processes or materials, such as ordinary plastic. Because ESD will not occur in the same electric potential or zero potential of material, so the work environment of processes or materials should be kept in the same static potential. Typically, these conductive or disperse materials should electrical connections to the same public places, such as electrical ground. In addition, to provide ground wire to the electrostatic hand ring belt, floor or table surface, safely reduce discharge and accumulation.
Because all generate static electricity cannot be completelyeliminated, so our third principle is that safely dispersed or those to happen in and electrostatic discharge. Proper grounding and electrical conductivity or disperse materials play a major role. For example, static electricity into the working environment for workers through static electricity hand ring or wear ESD control work shoes ESD floor mat stepping to eliminate them. Electrostatic discharge to the ground, rather than on the sensitive element discharge.
For some objects, such as ordinary plastic and other insulator, grounding cannot eliminate anti-static discharge. Typically, use of ions and the insulation on PD. Ion process produces the anionic, attracted to discharge a surface, thus effectively and electrostatic discharge.
The fourth principle is to prevent the occurrence of electrostatic discharge contacts to sensitive components and Assembly. One approach is to assemble the components and provide proper grounding or streaming, making any discharge of separated from the product. The second method is that in the appropriate packaging materials, packaging and transport of sensitive components. These materials can be effectively shielding products, reduce static electricity off in any of the products move from static electricity.
Finally, don't ask whether a process can produce ESD hazard, then guess the answer, you can test it. For example, using the field strength meter (fieldmeter) detect if possible harms of ESD electrostatic field exists. Measurement is the most secure method. You confirm and quantify those genuinely in need of electrostatic protection area, allowing you to concentrate on those areas of most concern. In addition, you can verify that those will not produce the harm of ESD, save you the cost of unnecessary protection.
These five principles become effective electrostatic control program. They help in the selection of appropriate materials and procedures for effective control of ESD. In most cases, effective program will involve all these concepts. In the development of control procedures, confirm that the sensitive element, sensitive level, and who has ESD hazard. And then see which concepts will protect these components. Finally, the selection and implementation can complete the tasks of the program and materials.

【Weak current College】】 signal source basics.

<br> 1. understand the function generator signal generator General divided function generator and arbitrary waveform generators, function generator is designed also distinguish between analog and digital synthesis type. We all know that digital synthesis-function signal source both frequency and amplitude and signal to .noise ratio (S / N) superior simulation, the phase-locked loop (PLL) design so that the output signal is not only accurate frequency, and phase jitter (phase Jitter) and frequency shift are able to achieve rather stable state, but after .all, is a digital signal, digital and analog circuit interference between, always difficult to effectively overcome, resulting in small signal output than analogue of function generator. Referring to the analogue function signal source, chart as follows: this is a universal signal generator for .analogue function structure, triangle wave generation circuit is based on the diode by sine wave shaping circuit produces a sine wave, and through the comparator compares the resulting square wave. The triangle wave is generated, the formula is as follows: in other words, if .a constant current source for capacitor charging, you can have a positive slope of the ramp. Similarly, the right to constant current source will be stored in the capacitor discharge of charge on that produce negative slope of the ramp, the circuit structure is as follows .: when the I1 = I2, to produce a symmetrical triangle waves, if I1 I2>>, which produce negative slope of Sawtooth wave, similarly I1 I2 <<that have a positive slope sawtooth wave. Then, as shown in .Figure 2, can be switched SW1 choice so that multiple charging speed is changed, the change in the signal's frequency is the frequency of signal source Panel of select switch. The same synchronization changes I1 and I2, or you can change the frequency, this is .the signal source, adjust the frequency of a potentiometer, just need simply be originally voltage signals into electrical current. The duty to adjust the design of any of the following two ways: 1, frequency (period), pulse width change, its methods are .as follows: change level, ie change square wave generation circuit comparator reference amplitude, pulse width can be reached to change the frequency of the same features, but its major drawback is the duty of General cannot be transferred to below 20%, resulting in sampling .circuit experiments on transient signals in the acquisition of signal changes, if you want to add this signal for analog to digital (A / D) conversion, the resulting digital signal changes and what to do. But undeniable use better. 2. duty cycle frequency .variable, followed by change, its methods are as follows: place the square wave generation circuit comparator reference margins be fixed (positive and negative can be using circuit switching), change the slope, to charge and discharge. In this way by design user's response .was "difficult to tune," this is a big drawback, but it can produce 10% duty ratio below is a sampling of the necessary conditions. The above two duty ratio adjustment circuit design ideas, has advantages and disadvantages, of course, the associated .also affects whether you can produce a "decent" sawtooth wave. The next PA (power amplifier) design. First is the use of operational amplifier (OP), and then make use of push-pull (push-pull) amplifier (note the .crossover distortion Cross-distortion prevention) will signal to the attenuation of the Internet, this section applies to signal source output signal indicator contains the SNR, square-wave signal rise time and frequency response, signal source, of course, is a sine wave signal .to noise ratio high, square wave rise time fast, triangular wave linearity better, while v-frequency characteristics are slightly better (ie, the frequency increases, the signal does not decay or cannot be reduced too big), this part of the circuit is .more complex, especially in the high-frequency capacitance for when in addition to the use of frequency compensation, also involves the PC Board wiring methods, it's all too easy, very easy to cause oscillation, want to designed this part of the circuit, in .addition to the original simulation theory base needed to have actual experience, "Try Error" patience is indispensable. PA signal out, after the π-resistive attenuator networks, namely the attenuation of 10 times (20dB) or 100 times (40dB), then .a basic function waveform generator that has been completed. (Note: selection of π-attenuation networks instead of divider circuit is to maintain a certain output impedance). A strong function waveform generator, and sweep, VCG, TTL, TRIG, GATE and frequency .meter, its design in this way: 1. Sweep: generally divided into linear (Lin) and the log (Log) sweep; 2. VCG: ie General FM, enter an audio signal, and signal sources its own signal generation frequency modulation; .these two design styles, 1 to produce a sawtooth wave logarithmic wave signal, and 2 input signal passes through multiplier (Multiplexer) select, and then the voltage on power conversion circuits, synchronization to add to Photo 2 of I1 and I2; 3. TTL .synchronization output: square wave with transistor circuit to 0 (Low), 5V (High) TTL signal. But note that TTL signal must longer buffered Mun (buffer) to output in order to increase the fan-out (Fan Out), sometimes also .in parallel to several buffer. But as long as the TTL INV NOT Gate can add; 4. TRIG functions: similar to the One Shot function, enter a TTL signals, you can let the signal source produces a cycle of signal output, design patterns .are no signal input, the figure of the SWI grounding; 5. Gate function: enter a TTL signals, signal source in input for Hi, generate wave output until the input is LOW, the figure 2 SWI grounding and turn off the signal source output .; 6. Frequency meter: in addition to market and easy dial displays, regardless of whether they are LED digital tube or LCD display frequency, the frequency meter circuits are overlapping, and block diagram below: <br> 2. arbitrary waveform generator, Simulink's .best instruments arbitrary waveform generator is a signal source, it has a signalThe characteristics of the source of all. Our tradition that signal source key to be logging circuits provide needed known signal (various waveforms), and then use other instruments measure the parameters of interest .. Visible signal source in an experiment and test processing, and does not measure any parameter is based on the consumer's request, the simulation of test signal to be logging circuit to test needs. There are a variety of sources, including sine wave signal source, .function generators, pulse generators, scan generator, arbitrary waveform generator, synthesized signal source, etc. In general the arbitrary waveform generator, is a special kind of signal source, integrated with other signal source waveform generation capabilities, and thus suitable for the needs of .various simulation experiment. First, the function function, simulation based laboratory designers environment function signal source is the most widely used general signal source, it provides a sine wave, sawtooth, square, pulse train, waveform, and some also have a modem and scanning .capabilities, we all know, in our basic experiment (such as University electronic laboratory, scientific research institutions research laboratory, plant development labs, etc), we designed a circuit, it is necessary to verify the reliability and stability, it is necessary to impose .the ideal profile to tell the true from the false. If we can use the source DC compensation function on solid state circuit control DC bias voltage level; we can on a suspect digital circuit, using the square-wave output signal sources as digital circuit for .clock, at the same time, use the square wave and DC compensation effective logic level analog output, observation of the health of the circuit, and confirmed the bug. In general use arbitrary waveform generator this basic function, capable of simulating your basic laboratory must .signal. Second, arbitrary waveforms, simulation of more complex signal requirements as we all know, in our actual electronic environment design of the circuit in the run, due to various disturbances and response exists, there is often the actual circuit signals defects and transient signals ., such as a pulse, peak, damped transient, frequency of mutations, etc. (see Figure 1, Figure 2), these conditions, such as the beginning of the design is not taken into consideration, there would have disastrous consequences. For example .in Figure 1 has a Department, if spikes to a shock poor circuit, may cause the device to "burn out". Confirm that the circuit on a position-sensitive degree, we can avoid unnecessary losses, the requirements in the aerospace, military, .railway and some cases are more complex and important areas of particular importance. Due to the arbitrary waveform generator special features to enhance arbitrary waveform generation capabilities, it often rely on computer communication output waveform data. In the computer transmission, through dedicated waveform editing software generated .waveform, and help to expand the instrument's ability to further simulation experiment. At the same time, due to editing an arbitrary waveform sometimes need to spend considerable time and effort, and each time you edit waveforms may vary so some arbitrary waveform generator, built- .in a number of non-volatile memory, random access editing waveform comparison, conducive to reference; or through random interface communications transmitted to the computer for further analysis and processing. Third, download, transfer, real-time simulation in the military, aerospace, .transportation, manufacturing, and other areas, some circuit running environment it is difficult to estimate, in experimental design is complete, in the real environment is also a need for further experimentation, some experiments of high cost or risk is large (such as the train .tracks transform when high-speed experiment, when the propeller aircraft on the run, etc.), it is impossible to judge the design for experimental products (such as high-speed trains, planes) feasibility and stability; we can use some arbitrary waveform .generator waveforms download function, in some trouble costs or risk large experiment, through digital oscilloscope and other instruments to waveform record, and then in real time through the computer interface to the signal source, direct download to the design of the circuit, further experimental validation .. In summary, arbitrary waveform generator is an electronics engineer signal simulation experiment of the best tools. We purchase is in addition to the interest in traditional signal source defects - - frequency accuracy, frequency stability, increase accuracy, signal distortion, should be concerned about .its editorial and waveform survival and download capabilities, while also noting that the number of output channels, so that synchronization can compare the two signal phase shift, further reach simulation State. <br> Figure 1 a sharp pulse of the digital signal <br> .Figure 2 a square-wave frequency of mutations.

【 Weak current College 】 IC common words 2 】

Acronyms in English, the full name of the Chinese meaning AAISAlarm Indication Signal alarm indication signal ALSAutomatic Laser Shutdown automatically laser turn-off automatic Protection Switching APSAutomatic protection switching Signal Processing ASPAdministrative Unit synchronized line snap signal processing Board AUAdministrative Unit snap AUGAdministrative Unit Group management unit group BBA22 x Booster Amplifier dual optical power amplifier Board BERBit Error Ratio BIPBit Interleaved Parity error bit plug parity between CCMConnection Matrix connection matrix CMISECommon Management Information Service Element common management information services unit DDCCData Communications Channel data communication pathway EECCEmbedded Control Channel embedded control channel EOWEngineering Order-Wire engineering liaison line (official) ESErrored Second error seconds FFALFrame Alignment Loss frame synchronization loss FEBEFar distal End Block Error into block error FERFFar distal End Receive Failure receive failure GGTCGeneral Timeslot Cross-connection universal slot cross connection plate HHCSHigher order-order connection Connection Supervision Order supervised Assembler-order Assembly HOAHigher HOIHigher Order Interface-interface HPHigher order Path order-order paths HPAHigher Adaptation-order Adaptive Path HPCHigher order Path Connection order-order paths connect HPOMHigher Path Overhead Monitor high-order paths overhead monitor HPTHigher order Path end Termination-order paths Of out-of-step Frame frames LLOFLoss LOILower Order Interface lower order interface LOMLoss Of Multiframe LOPLoss complex frame loss Of Pointer pointer missing LOSLoss Of Signal loss of signal Path LPLower order order low-order paths LPALower Path Adaptation-rank pathway adapter LPCLower order Path Connection order low-order paths connect LPOMLower Path Overhead Monitor low overhead monitor LPTLower order Path Termination of low-order paths end LTILoss all Incoming Timing references LUGLower order path Unequipped Generator MMCFMessage Communications Function message communication function Relative Time Interval Error MRTIEMaximum MSMultiplex Section multiplex section MSAMultiplex Section Adaptation multiplex section adapter MSOHMultiplex Section OverHead multiplex section overhead MSPMultiplex Section Protection multiplex section protection MSTMultiplex Section Termination multiplex section end MTIEMaximum Time Interval Error NNDFNew Data Flag NENetwork Element element NEFNetwork ElemenT Function element function NNINetwork Node Interface network node interface Administration and Maintenance OOAMOperation running, managing, and maintaining OHPOverhead Processor overhead processing Board Of out-of-step Frame frames OOFOut PPD1PDH Double 16-line E132x 2048kbit/s electrical interface slip plate PDHPlesiochrous Digital Hierarachy plesiochronous digital hierarchy PDHPlesiochronous Digital Hierarchy plesiochronous digital hierarchy PJEPointer Justification Event pointer adjustment event PL1PDH Line E116x 2048kbit/s electrical interface slip plate PL3PDH Line E3/DS33x34368kbit/s, 3x44736kbit/s electrical interface slip plate PL4PDH Line E4139264kbit/s electrical interface slip plate POHPath OverHead path overhead PPIPDH Physical InterfacePDH physical interface PSEProtection Switch Event MSP event PWSPower Supply second power plate RR16Receiver of STM-162488320kbit/s synchronous lines optical receiver plate RMSReligion Management System area management system RSRegenerator Section regeneration section RSOHRegenerator Section OverHead regeneration section overhead RSTRegenerator Section Termination regeneration period end SSBSSynchronous information Bone System synchronization information backbone system SBSMNSBS Management NetworkSBS NMS SCCSystem Control & Communication system communication control SDSignal Degrade signal deterioration SDHSynchronous Digital Hierarchy synchronous digital Hierarchy SDHSynchronous series Digital synchronous digital series SDXCSynchronous Digital hierarchy Cross-Connect synchronous digital series cross SE22 x Synchronous Line STM-1 Electrical155520kbit/s synchronous lines double-interface board SEMFSynchronous Equipment Management Function to synchronize the device management feature SESSeverely Errored Second serious error seconds SETGSynchronous Equipment Timing Generator synchronous equipment timing generator SETPISynchronous Physical Interface Equipment Timing synchronization equipment scheduled physical interface SETSSynchronous Equipment Timing Source synchronous equipment timing source SL1Synchronous Line STM-1155520kbit/s synchronous lines optical interface board SL22 x Synchronous Line STM-1155520kbit/s synchronous lines bi-optic interface board SL4Synchronous Line STM-4622080kbit/s synchronous lines optical Line interface board SLESynchronous STM-1 Electrical155520kbit/s synchronized line electrical interface board SLMSignal Label Mismatch signal mismatch SPISDH Physical InterfaceSDH physical interface STGSynchronous Timing Generator synchronization timing generator STMSynchronous Transport Module synchronous transport module TT16Transmitter of STM-162488320kbit/s synchronized line light send Data sheet TDATone & Access audio data interface board TMNTelecommunications Management Network telecommunication management network TUTributary Unit branch unit TXCTributary Cross-connection for STM-162.5G low cross connection plate XX16High-order Cross-connection for cross-connection panels STM-162.5G-order

【 Weak current College 】 monitor failure and dissolution 】

Individual and small computer on the Internet forums, often see such as the "monitor failure! first aid ..." topic of the post.   Although many people have little trouble yourself with good habits, but whether amateur or professional service personnel, some monitors common failure "awareness of the incidence of" reason to exist on more or less mistakes. These errors typically become maintenance "Tiger" or the "sequel". Therefore the author's pick out 13 the most representative of misunderstanding, the point of failure to carry out instructions. Hope this article will allow you to rediscover your monitor common failures of the real cause of the "onset" and the right approach, thus less walking some detours ^ _ ^. (Note: only refers to the common fault of not including difficult diseases), the screen is color fault symptom: 1, just post the entire screen is red (partial color display with back sweep lines), but an eyelash is normal;
2, in the use of occasional screen red phenomenon, but is also a blink it correctly;
3, the entire screen is blinking white red and with a very heavy and Flyback line immediately protective shut-down (or black screen and can't boot up). Misunderstanding of the point of failure:
For this kind of trouble a lot of people are said to be the graphics card has a hardware fault, and some say is the CRT scrap, it was also said to be the video driver is damaged, these views are wrong. Failure causes and countermeasures: indeed, pengji this picture tube failure will cause this symptom, but not beyond repair??   Minor available electric shock, serious power supply can be rewound filament winding, and sometimes a one hue depending on power supply of the electron gun resistance soldered or a circuit breaker of damaged or resistance larger will cause such symptoms. In addition, there are some models just has some minor interelectrode leakage, usually without maintenance, but there are moments when powered on, the partial color seconds to normal (1st symptoms). For pengji (sometimes only electrical leakage) fault you only to professional service personnel for maintenance, its characteristics are usually protective shut-down. Failure reason and solution: usually use 2 years with colour display appears this fault, the real reason most cases is the CRT tube socket moisture caused by oxidation, as long as the replacement of the original new pipe, block will be able to troubleshoot. But some say in the plug in the new pipe, block before you find a small piece of sand the picture tube tail after projecting pin grinding clean, aims to get rid of the oxide layer, which is like a snake.   When I replaced the CRT tube socket, some did pin some oxide on, but these oxides are missing in the original tube socket to pin, just use the xiaomao brush to clean sweep. So far I have not seen the PIN be oxidized, but because of the force is too large to make the PIN leak and damage the picture tube at the situation is encountered in a few cases, we do not use sandpaper to Polish, avoid damage to the "death" of! if you replace the socket will replace the ineffective, but this high package work the author recommends the best you can do is find professionals! plus, some models depending on the part of the circuit are special, sometimes after a failure will cause image fuzzy, but now usually brightness and row, field level also have an exception for this type of failure points the author recommends that you deliver professional treatment! if not brand-name products with colour display and use the year has been very long, so I recommend that you seek professional electrical maintenance departments for replacement tube socket, avoid neck after leakage accidents such as responsible:). third, the use of image blur fault symptom: 1, just post the image clear, but with the use of time and the increasingly blurred; 2, in the use of images are blurred, but occasionally will soon be back to normal, but with a few days or a few months after more and more serious, more often. Failure point of misunderstanding: it was considered that such failure is the monitor line circuit question??   May be a line pipe, backward diodes, capacitors and other components of backward thermal stability is not good or are soldered. These awareness can be said to be totally wrong, because these components do not have a clear image or not. Failure reason and solution: in the first symptom of genuine fault point is usually very high package focus knob on Aging, you can replace a high-pressure package a try. Of course, if you monitor the use of the year has more than six years, then we also want to consider the possibility of a kinescope aging. In addition, there was a time I taught for a number of professors initiates a this symptom of camera turned out to be the seat tube and depending on the plate of large negative electrode copper foil exists due to leakage phenomenon (after analysis like design problems), so sometimes in maintenance difficulties can replace a genuine pipe, block a try. For the first symptom is usually the CRT tubes, quality is not high, you can replace the new products to solve the problem. 4. screen flashing fault symptom: 1, screen edge is flashing phenomenon;
2, the entire screen with flashing phenomenon;
3, one corner of the screen is blinking. Failure point of misunderstanding: many people think that this is the power of the power supply voltage or instability caused by some "experts" even speak because some with electronic ballast lighting or electrical appliances to the interference of the monitor's power supply, some say is the video card hardware failure has occurred. In fact, these views are wrong, because the monitor on the voltage requirements is not very strict?? At present, the vast majority of colour TV in 100V ~ 240V power supply voltages. Of course, if the voltage is too low or too high voltage fluctuation, the other when don't recognize on, but the last two years, countries inthe implementation of the national rural network after the transformation has already begun to fundamentally solve the previous rural voltage instability, low voltage, but these issues are often in the city is not present, so these factors is no longer important. As regards other electrical equipment can cause interference even more out of the question, after all, the monitor's use is not a mutual inductance type voltage-stabilized source, besides other electrical interference even bring the screen flicker! fault reason and solution: create the first twoClass real symptoms, usually the cause of the malfunction is due to the line circuit parts components soldered or power at + 300V filter capacitor capacity decrease. While the latter unlikely?? Only in individual models and their more serious loss of capacity will result in a human eye can discern in Flash. In addition, some models depending on power supply part of the circuit are special, sometimes the portion of a components soldered also cause this symptom. Of course, if you put the monitor resolution and refresh rate is set too high or too low, can also cause this type of failure, so you can put the resolution and refresh rate settings into intermediate values try (Note: long-term working to overclocked State will make certain components aging and appears this fault, and compare to find the point of failure). There is a video card or monitor driver exists BUG, you should first try to update the driver. If the above processing is not valid, you can focus on producing high-voltage check package acceleration voltage and high voltage is normal, because sometimes these two voltage anomalies can also cause this kind of phenomenon.   Note: If you turn on the TV set also have Flash, it will first check the mains power supply is a problem??   If the size is too small or too large, such as voltage fluctuation ('d electrician check). In General, this type of fault repair requires you to have a certain degree of ability andprofessional knowledge, so I recommend if you exclude a simple breakdown after repair, delivery of electrical maintenance Department for processing. Sometimes some with magnetic materials (such as some low-end power pod or ADSL, Cat Power, etc.) in the vicinity monitor will cause the screen flashes on a corner, so get this phenomenon to try to clear the display items look around, often the problem can be solved.   5. water ripple on the screen failure points of misunderstanding: it is a platitude ^ _ ^, but I still have to say that, because some people think that only inferior product or hardware fault monitor appears water ripple.   Not necessarily, because almost all CRT monitors have water ripple, but there is light weight, usually as long as the monitor at 800 × 600 and above resolution no water ripple, but only at 640 × 480 resolution under water ripple is normal (screen all white is more obvious), and no hardware failure. Failure reason and solution: If you are more than 800 × 600 resolution still water ripple words will note, if you are not out of warranty, you may find relevant departments to theory, if had been a warranty, you can replace a + 300V capacitance try, if invalid will deliver professional maintenance departments.   In addition, it has been said that such failure is the video quality problems (such as shoddy work, etc.), according to the author of this possibility is not great, but I also never met resulting failures, so can't waste a conclusion, but you'd better not repair it but also as an important "suspects" to avoid detours:).   6. There is interference on the screen failure failure phenomenon: the screen always has a persistent irregular interference clutter or thin black lines with the "pop pop" noise. Misunderstanding of the point of failure: this symptom, there are a lot of people think that is the monitor power of anti-interference ability is poor, think that for several power Department of filter capacitor can settle out, some people even think switching power supply's switch there is a problem with the pipe, these views are wrong. Failure reason and solution: the real cause of the malfunction is usually high pressure nozzle and high pressure tube Cap between striking phenomenon. Of course, there are a lot of maintenance personnel can quickly analyze this is due to the high-voltage spark at the mouth, but there are a lot of people approach are not quite right. Some people may even put the butter to high-pressure nozzles to prevent a recurrence of the high-voltage spark, while the use of butter on the monitor, no harm, but the pressure values might not be very high, so it is very likely to other service personnel and users being shock hazard.   Therefore it is best to use "high pressure grease" repairing?? In the add high pressure grease before you use absolute alcohol let high pressure nozzle, Cap clean (even if rust rust or get a new CAP) with hair dryer and drying. In addition, sometimes the tube's pipe, block a striking phenomenon also appears on the symptom, but it will be accompanied by an image when the clarity of the hit-or-miss, then just replace the original pipe, block you can get!   7, display brightness too light and does not dim the misunderstanding of the point of failure: If the display brightness too light, even if the brightness is "0" or very bright, some people will think this is the display brightness automatically out-of-control circuit, this view is not very correct?? Although the control circuit out indeed cause this phenomenon, but usually it is not out of control. Failure reason and solution: the vast majority of cases this fault is apparent on the level of power supply filter capacitor capacity decrease or open (or virtual) welding, so you can try before welding, if the failure is still just replace the new capacitor to whom are the point of failure, if still not settle will look depending on whether there is a power supply circuit breaker, above all normal again when the brightness control circuit automatically suspect (unlikely).   Note: sometimes memory fault will also contribute to this phenomenon, but the probability is very low. 8. display color exception fault symptom: there are several places on the screen, color, or screen color anomaly at the edges.   Failure point of misunderstanding: some people think that this is the monitor long-term continuous AC or geomagnetic, but at present, the vast majority of monitors and will not appear this fault?? With colour display of degaussing circuit is different from TV. Failure reason and solution: Although this is quite typical CRT magnetization of symptoms, but this symptom is usually placed near the monitor has high magnetic products or degaussing circuit fault exists. High magnetic products mainly refers to the brand of poor quality speaker, due to the genuine brand-name speakers with almost all of the speakers are non-magnetic products, so as long as you use brand-name speakers or other brand placement from the monitor's loudspeaker 30cm outside can effectively prevent and eliminate faults appeared. If this is not due to the high magnetic products, you can manually once the degauss (method reference says:Certificate), if the image does not have one when degaussing obvious swaying the degaussing circuit exception, then you'd better delivery professionals for maintenance. Note: If the long-term early monitor power really causes the picture tube is magnetic, but use this class to display the user has very little.   9. image distortion failure points of misunderstanding: some people think that as long as you set up the display settings on the list, indeed, if this phenomenon is man-made, then as long as a diversion, but this is rarely appear?? Unless a rookie in Rookie ^ _ ^. Failure reason and solution: its common failure point is typically a line or a correction of a problem (such as S calibration capacitor, etc.), since maintenance up to have the professional knowledge, so I recommend that you deliver jiadianweixiubu door for repair.   Of course, if the failure is when you monitor what actions occur, then you can reference manual to do some debugging correction work try, as long as you carefully read the instructions are usually able to fix it!:)   10, contrast, low fault symptom: the so-called contrast low is layered, and colors as previous gorgeous. Failure point of misunderstanding: many people in the adjust contrast invalid after that is contrast control circuit has failed or is aging, kinescopes those views is not quite correct.   Failure reason and solution: in most cases this is due to the dust on the display too much, of course, we cannot exclude that the contrast control circuit parts causing the problem, but the possibility is very small, but staff almost unable to spare for maintenance, cleaning of the display screen is invalid after the best looking professional electrical maintenance personnel for maintenance. 11. Black fault symptom: power on, the host on the monitor does not have any complain, and monitor status LED display normal, power switch are normal, but there is no image (solid black), but sometimes lashing out with colour display enclosure or occasionally post when it is displayed properly, but use some time after the situation has gotten worse over time.   Failure point of misunderstanding: the fault seems obvious is the circuit where there is bad, but many people do not have idea what places. Failure causes and solutions: so that you can first look at filament power supply circuits for soldered components or solder joint, usually this is the cause of such failure.   Of course, sometimes causes the host since the host also black, but whether you get slapped with colour display case would not have improved, conditional to the monitor is not a determining received no fault host a try. In addition, there are now many monitors in pull even in the video signal cable appears after the post display function, if the monitor displays normal basic no fault, the fault point in the signal line or video card, so can more easily find the point of failure.   Note: in view of other black screen in the cause of the malfunction, the professional strong do not. 12. the no fault symptom: 1, color display at power on is no reflection, even the indicator is not lit;   2, a power-on what image also didn't see the protective shut-down. Failure point of misunderstanding: anyone seen this type of fault would say this is just a small failure, change a fuse is OK; some say that this is the video card driver is broken, this is not true. Failure causes and solutions: as the monitor's fuse is the time delay fuse?? That allows instantaneous flow much greater than the rated current of high-current, so that usually exist short circuit fault will burn this insurance, you are a new fuse will fuse again, of course, if fuse looks no exception, but it is not, it may be the aging damage when a new fuse can work, but this is a rare experience. As for the driver is a fallacy to say?? Before outside of WINDOWS is not the driver.   For 1st symptoms, such as power cables, power sockets and plugs can sometimes be "tough", so you have to exclude the possibility of simple, if you exclude a black screen after, you have to find professional service personnel for maintenance. Note: If you enter the system becomes black screen should test virtual video driver. For the first two symptoms you may have to enter the self test with colour display shows or simply received another host on try, if not then lit a faulty proof circuit, this kind of failure I recommend delivery professionals for maintenance;   if you can light up words and descriptions is a host, such as the video card and the motherboard and CPU, etc, you may be able to use the Replace method to do the check. 13. the system cannot recognize the monitor failure phenomenon: sometimes into WINDOWS after a system report found new hardware and automatically install the driver,Device Manager, turned out to be a monitor into unrecognized monitor. Failure point of misunderstanding: some people think that this is the display out of the hardware failure or a component caused by poor performance, it was considered that the video out of the hardware failure or a video driver is damaged, it was considered that the monitor and video card connected cable problems, some people believe is the VGA socket problems, these views are wrong. Failure reason and solution: a failure occurred to plug the monitor, and is used for a long time and after the failure. The reason is not installed the monitor manufacturer's proprietary display driver, you need to do to the manufacturers Web site to download the appropriate monitor drivers and install to get it!:)   Conclusion in my previous maintenance process, awareness of these failures or errors, or have existed had to walk quite a few detours. But after I repeated practice of weighing, finally found the real point of failure, but also from the many failures have summarized a law?? The real point of failure are often not deeply hidden components (reason) and are usually very simple local presence. But most people in the maintenance will experience main committed "Meaning "and" dogmatism "errors, often to the point of failure is a complicated and very few people have the habit of" curiosity ", so often causes large detours. Of course, experience or essential and very important, but we must also learn the specific problems of specific analysis of skill (ideas) it ^ _ ^. Well, not much to say, hope this article gives you some insight on the maintenance of thought.

【 Weak current College 】 buy digital camera should note 】

Buying a digital camera, the best advice is: take it easy, don't worry. Do not watch it at a discount to buy, this is important because discounted goods are often outdated, or will be updated instead of more advanced technology.

When you purchase a digital camera, take note of the following:
Buying a camera, it was actually buying a "negative". Resolution camera built-in fixed, not maximum resolution in sensor on the basis of increased. If the image detail is important to you, then select camera, paying particular attention to the maximum resolution of the camera.

Most prices relatively moderate digital camera as a fool, not like SLR cameras that can be user control features. This means that you can only hope that manufacturers in an established price down to the camera configuration to the broadest possible range of control devices. And Pns cameras, optical accessories or other accessories not many. Some digital cameras and 35mmSLR camera is similar, but the prices are very high, so they are only suitable for professional photography.

In a Word, you must be careful to determine what your own image, and purchase the most suited to your needs with the camera.

Finally, a digital camera needs to be saved in memory of photo storage. In order to achieve a more reasonable price/performance ratio, a digital camera usually compress images in various ways. Effects of compression on the image quality is high, some compression system requires the adoption of clear image detail and color information for the relatively small size of the image. This is a direct result of the filmed image sensor has weakened. But at present there are very few cameras store images in the compresses, additional information is not lost.

1. the sensor (CCD, CMOS)
Digital camera resolution not less than 1024X768, so you can catch more image details. Digital cameras use two basic types of image sensors: CCD and CMOS.

CCD camera prices are more expensive, most likely in the coming years it is in the position of inexpensive cameras are CMOS technology. CMOS cameras are currently has just been listed. One thing to be careful: do not use interpolation resolution and confuse the actual resolution.

2. metering system
Exposure table, also known as the camera light meter, in occupies a very important position, as it should, according to the shooting scene to set the shutter speed and aperture.

Best metering system is the "zone metering" or "multi zone metering." In these systems, the camera will capture image is divided into several zones, each zone consists of a camera metering system for estimating separately. Then put the results together, using a special calculation method to determine the best exposure. Then under the metering system-provided information to determine your camera's Aperture and shutter speed. At present, with many regional metering of digital camera is not very much, but this situation is gradually changing.

Today, most digital cameras use a central focus of average metering. This metering focused on Center, and then and the entire screen of metering average values to determine the ultimate exposure. This means that the camera at the darker object, the image of the remaining parts will be overexposed, conversely, too. View the camera's exposure only way is to type a try. Thankfully, most digital cameras in use, you can browse to the image on the LCD screen, the camera metering mode.

Finally, remember: overexposed image areas do not have any available data for future use image editing software can not be recovered.

3. lens
Most digital cameras are equipped with a wide angle lens, equivalent to 35mm camera 30 to 40 mm range. Shoot in this focal length, image distortion occurs, especially in the vertical direction. For this reason, most users still prefer aspherical lens. In addition, with automatic focus, high quality glass lens to any camera is important, especially in macro mode. There are also people who believe that fixed focal length lenses with more easy shooting, but when it's close to the subject object constraints is relatively large.

The lens is also very important. The lens of "F" the number, the small bright (F2.0, F2.8). Lens "F," the higher the value, the maximum aperture is smaller, so it can only make a small amount of light reaching the sensor, the shutter speed is reduced. A lower shutter speed means an image easily blurred shots, especially when photographing and filming is vertical when you move an object.

Finally, note the lens cover is not very easy. Preferably in the lens cap on the lens can be strings, so that the lens cap strap is not easy to lose. Do not look down on such a small lens cap, usually the original manufacturer's product are expensive to be true, so you'd better be careful. Whether you believe it or not, some fairly expensive camera lens was not conspiracy, if you buy this camera, you have to always be careful not to put the lens cap to lose, or you can own the lens cap on wearing a hole, JI on a piece of string.

4. the image compression
Almost all cameras are image compression and storage. Most are made as JPEG compression damage. Regardless of the compression level, how to, definitely lost colors and details. Now apart from professional cameras, more and more cameras start provides lossless compression TIFF format. This option is very popular with users ' favorite, but the picture file is relatively large, there are many 2048X1536 9Mb, most of the memory card are stored not a few. With the memory card capacity increases, the issue should be can't be effectively addressed. But we still hope that manufacturers can provide similar to RAW files smaller lossless compression format. But in the present circumstances, it would be better to focus on the camera in the best resolution generated the final file size. Image file size is smaller than the compression ratio 300K that is relatively high, this is likely to lose many of the details.

5. memory
Memory is essential for digital camerasIt is now indispensable device for digital cameras. Different manufacturers of memory differences are considerable. New models equipped with a removable storage card or built-in storage unit or both. Some cameras have a built-in storage units, only the storage card, it will be according to the manufacturer and camera model. Some older models only a fixed amount of memory and cannot be expanded, you'd better not to buy such old models. And different types of camera, built-in storage unit capacity is different, this indicator will affect the camera store file, continuous shooting speed. Therefore, other things equal it is best to choose a larger memory.
6. the digital and optical zoom
Because most civilian grade digital camera lens can be replaced, so many of the camera has a zoom feature. But you have to keep track of what is optical zoom and digital zoom. If you are the optical zoom is more practical. It should be noted that the lens is of maximum aperture will zoom to the telephoto end become very small, if so, in the telephoto end shooting your shutter speed would be impossible to get a higher shutter speed, it's possible photographs will be virtual. Note: digital zoom and not much use. So do not report on the digital zoom is too large, it is very banal, just put the photos for local amplification.

7. optical viewfinder
Be careful, some digital cameras there is no optical viewfinder, if you buy the camera, do be sure to have a spare battery. The LCD screen as a viewfinder, will soon run out of battery. Worse, most of the LCD screen in outdoor use under bright light. Purchase camera best equipped with a size suitable for the optical viewfinder. Many of the viewfinder size is too small, or no diopter adjustment, glasses of the user in the use of extremely uncomfortable when they feel, and many of the viewfinder is unable to correct the parallax. So be careful and be sure you're on camera viewfinder quite satisfactory. For paraxial viewfinder camera must have Parallax correction line and the diopter adjustment knob, if you can buy the TTL of the viewfinder so much the better.

8.LCD display
Digital cameras are usually equipped with a LCD display screen, it can be stored in the camera image preview and playback and delete. The best LCD monitor for active matrix (ActiveMatrix), because they show the brightest of the screen. The disadvantage is that it is better than any other type of LCD display power-intensive. Recent passive matrix (PassiveMatrix) display screen technology for some improvements, the screen clarity, even in outdoor is also clearly visible. But remember: LCD is famous for it's electric Tiger, you'd better save point.

Finally, do not see the LCD screen displays the photo effect is good to make a purchase decision. LCD screen often see on the actual scene of brighter, more saturated. By the way, check your camera's display screen location, because some camera display location not too good, in the optical viewfinder viewfinder nose dome in the LCD, you have to spend considerable time to wipe the grease stains nose forward.

9. control design
Complex control device is really annoying. Digital camera control unit should be easy to operate and understand, the user shall not be liable to the user manual to normal operation.

And control devices should be easy to reach, it is better not to frequently used features to the menu settings. If the photograph before you have to move the camera to the nose to find the control button, you will lose many opportunities.

10. Flash
A built-in Flash is very necessary. The camera should configure basic Flash control, in the light of local can auto Flash or Flash, turn off, for small portable camera must be equipped with a red eye removal function prevents shoot out of every one like rabbit eyes. If possible, try to buy a slow-sync Flash camera door, this function can take photos with a night person, let the characters and background have access to accurate exposure.

You should note the Flash range and regional or its index. Some types of Flash cannot fully cover shot of max shooting angle, angle of the photograph appears black. There are a number of Flash's range is too small to shooting distance distant objects. Finally, we need to pay attention to what the camera can add an external flash. General Flash shoe or external Flash sync terminal of the camera a little better.

11. image processing speed
After the photo shoot, digital camera, you must put the image stored in the memory. Image processing time from several seconds to several tens of seconds. During this period, the camera does not work, and is very sensitive to vibration, so time is as short as possible.

12. software
A digital camera is not enough, to get photos, you must leave it connected to your computer. Take a look at the camera onboard, and see if there is one called TWAIN driver attachment. This software can be downloaded from the image to the computer, or should have a plug-in (PLUG-IN). Most manufacturers will provide some image editing software, you can make adjustments to the image. Even on PHOTOSHOP like image software unfamiliar or you can use these simple software for image reset size, trim, adjust the contrast, color or sharpening. Carefully checked bundled software, some parallel imports is not this.

13. connection
Most cameras use the serial interface is connected to your computer, but this connection transfers data more slowly, no longer meet the increasingly large image files. Some manufacturers offer IrDA connection, use infrared to transfer the data. But your computer must be equipped with this function, there are many laptops and desktop PCs but very few. Some manufacturers provide IEEE1394 or USB connection mode, both the download speed is very fast. One IEEE1394 is mainly used in professional models, but the computer must have IEEE1394 interface; UComparison of universal SB, and general computer motherboards have a USB slot, is the ideal connection. If you do not have a USB connection, you can buy a USB card reader, you can only read a card, some are compatible with SM, CF card. You can most camera equipped with a cable. Some camera provides only the cable for PCs, Macintosh cable is intended for alternative. Make sure you select the camera to your computer is properly connected.

14. white balance control
This is a very useful feature. White balance enables you to control the camera filming scenes of judgment. Using this control, you can prevent a generation too dark, too bright, or because the colors are fluorescent light transfer of images. Mid-range and professional digital cameras often have this function. Although most cameras are equipped with automatic white balance control, but in a different light, auto white balance is still not fully meet the requirements. So the more senior digital camera provides multi-level white balance allows the user to select the light source.