【 Weak current College 】 according to different definitions of classification 】 wireless microphone

According to the different classification definition wireless microphone
Depending on the definition, wireless microphone can be divided into a number of different types. 1. in accordance with the emission frequency of use and distinction: a. FM wireless microphone: commonly known as FM is the FM 88-108MHz international FM radio frequency band. Early consumer wireless microphone is the use of FM radio to receive the system simple, low cost, but due to the use of results, are able to meet the requirements of professional quality, and currently can only be a child or student toys. B. VHF wireless microphone: is divided into low-frequency and high frequency bands the use of two types, the former VHF50MHz band, less frequently, use the antenna length is too long, and the most vulnerable to various electrical interference of clutter, so this type of product, has now been replaced by high-frequency band and gradually disappeared from the market. The latter use VHF200MHz band, due to the higher frequency, use the antenna is shorter, you can even design a concealed antenna, convenient, safe and beautiful, from the clutter and greatly reduced, very mature, circuit design parts for universal access to affordable, so become popular on the market today aircraft types. 2, according to receive by way of distinction: a. automatically selected hearing to receive wireless microphone system (receiving True diversity wireless system): since the radio traffic will have a "dead ends in" (Dead-point) physical phenomenon in the receiver's sound output, resulting in intermittent or unstable disadvantage, in order to address this shortcoming, the professional use of aircraft must adopt the dual antennas and double tuner to receive an auto-selected "," (Automatic switching diversity receiving) ways to improve. B. non-auto selected hearing wireless microphone system (Non-diversity receiving wireless system): these models of circuit design complex precision, assembling the difficult, expensive, low-priced models without the use of automatic selection of the design, so it does not remove the wireless microphone in the use of sound interruptions. This aircraft is certainly not able to comply with the professional use of basic requirements. 3. by way of distinction according to the oscillation: a. quartz locked (locked Qualtz) aircraft: quartz oscillator produces transmit and receive accurate, stable, fixed frequency, the circuit is simple, low cost, is the standard for today's wireless microphone circuit design. This type of microphone and receiver only fixed single frequency pairs used to change or adjust the frequency of use. B. phase locked frequency synthesis (PLL Synthesized) models: in order to avoid wireless microphone in-use experience other signal interference and the inability to use, or to simultaneously use multiple microphones, you need at any time convenient and rapid changes in the channel, so using PLL circuit design, to meet the requirements of this function. 4, according to the number and the distinction between the receiver channels: a. single channel types: in a receiver box only assemble one channel of the non-automatic or automatic selection before the receiver, the former market in Taiwan, but there is almost no export market due to the cheapest, but it is a (large color cargo). The latter characteristic due to the use of simple, stable, and is suitable for professional occasions multi-channel use, avoid signal interference of the best machines. B. two-channel models: in a receiver box, the Assembly two channels of non-automatic or automatic selection of any receiver, making full use of the chassis of space and cost. The former is the so-called "Asia fighter type" model, because the design simple, low-cost mass production to become Taiwan's major aircraft manufacturers. The latter because institutions and circuit complexity, processing of internal interfere with each other and the antenna is mixed matches, only a few in the production of professional aircraft manufacturers are models. C. multi-channel models: in a receiver box, the Assembly of more than four channels, mostly using the receiver modular design of the receive module. Mainly suitable for loading rack to use professional models.