With the advancement of society, the development of the economy, and the improvement of people's living standards, the use of walkie-talkies has brought a lot of convenience to people. How does the walkie-talkie match the FM? First let's talk about the principle of the walkie-talkie. The English name of the walkie-talkie is two way radio. It is a two-way mobile communication tool. It can talk without any network support, and there is no call charge. It is suitable for relatively fixed and frequent calls. There are currently three types of walkie-talkies: analog walkie-talkies, digital walkie-talkies, and IP walkie-talkies.
    The working principle of the walkie-talkie is as follows: 1. The transmitting part: the phase-locked loop and the voltage-controlled oscillator (VCO) generate the transmitted RF carrier signal, and after buffer amplification, the excitation amplifier and the power amplifier generate the rated RF power, and pass through the antenna low-pass filter. , suppresses harmonic components and then transmits them through the antenna. 2. Receiving portion: The receiving portion mixes the amplified signal from the radio frequency with the first local oscillator signal from the phase locked loop frequency synthesizer circuit at the first mixer and generates a first intermediate frequency signal. The first intermediate frequency signal further cancels the adjacent channel clutter signal through the crystal filter. The filtered first intermediate frequency signal enters the intermediate frequency processing chip, and the second local oscillation signal is mixed again to generate a second intermediate frequency signal, and the second intermediate frequency signal is filtered and removed by a ceramic filter to filter out unwanted spurious signals. Generate an audio signal. The audio signal is amplified by amplifying, bandpass filter, de-emphasis, etc., into the volume control circuit and the power amplifier to amplify, drive the speaker, and get the information people need. 3. Modulation signal and modulation circuit: The human voice is converted into an audio electrical signal through a microphone. 4. Signal processing: The CPU generates a CTCSS/CDCSS signal that is amplified and adjusted to enter a voltage controlled oscillator for modulation. The low frequency signal obtained after receiving the frequency discrimination is filtered and shaped by the bandpass filter of the amplification and sub-audio, enters the CPU, compares with the preset value, and controls the output of the audio power amplifier and the speaker. That is, if it is the same as the preset value, the speaker is turned on, and if it is different, the speaker is turned off.
    How does the walkie-talkie match the FM? Need to pair with each other, you must have the software and frequency line (data transmission line) of the walkie-talkie, then read the frequency through the software, take one of the walkie-talkies as the host, and finally write into another machine, you can Intercom use.
    The above is the introduction of the intercom and walkie-talkie how to match the frequency of the content, I hope to help everyone.
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