College】 【weak tone of the basic knowledge】.

<br> <BR> the tone of the basic knowledge of the most common tone is CTCSS (Continuous Tone Coded Squelch System), direct translation is Continuous Tone Coded Squelch System, is Monia sound, Motorola known as the PL, the frequency range from 67.0 .Hz, 69.3 Hz up to 250.3, a total of 39 tone points (or 50 points). .Launch can not hear this low frequency signal (so called tone) frequency added to the continuous firing, the other only received only way to receive the same frequencies for interference, or do not listen to their signals are not .. .Asia Yinfen launch of two sub-tone sound and reception. .General order to the relay, is launching the tone used, so as to open the trunk. .The relay is used in their "receiving the tone," and no tone signal to be repulsed. .Some do not relay the signal down the tone with the tone, but also with the. .Similarly, their reception, in order to reject themselves do not need to hear signals can also be coupled to receive the same tone, used to exclude external interference signals. .Although the tone is, in fact, can be heard, especially the tone set in the high limit (250 Hz around), or better frequency response of the receiver when the low frequency. .Therefore, we set the tone when set lower as much as possible in order to avoid unnecessary interference. .There is another tone is DCS (Digital Coded Squelch), is the tone number, Motorola known as the PL, the tone of 104 points (DPL less), more advanced, and fired at the end of speech before the use of digital encoding .form of emission. .This tone can both transmit and receive (ie can not set emission not only receive). .Some people think that the tone transmitter, the receiver is only set to the tone receiver to receive. .In fact just the opposite. .Transmitting the tone, the receiver is set to "non-tone receiving state" must be able to receive, set to "tone receiving state" must be consistent with the tone type, while the tone in order to receive the same code. .For example, VX-1R and VX-2R, "T" that launched CTCSS tone, "T SQ" said transmit and receive CTCSS tone, "DCS" said the tone DCS transmit and receive..