What Are The Four Working Modes Of The Marine Walkie Talkie?
1. Transmission mode: The voice is collected by the MIC (microphone). If the VOX function is turned on, the signal is sent to the MCU for identification. The other channel is combined with the signal after the MCU responds and sent to the transmitting circuit.
2. Receiving mode: In this mode, the transmitting path will be closed, and the demodulated signal will be divided into three channels, one through the tone filter and the comparator to the MCU to check whether it is the same code; one way is sent to the voice processing In part, if the code is the same, the signal is sent through the speaker, otherwise it is muted; there is also a signal sent to the noise detection circuit, which consists of a noise detector, a squelch detector and a comparator.
The circuit controls the squelch level on the one hand. If the user selects a higher squelch level, the anti-interference ability of the Waterproof Marine Radio will be strong, but the communication distance will be shortened, and vice versa.
On the other hand, the squelch detector also controls the listening function. Usually, when the signal is weak, it will not be sent to the speaker. The monitor is to hear the weak signal, let the squelch detector turn off, the signal is sent directly to the speaker, and the voice is discerned from the noise.
3. Call mode: This function is relatively simple, just establish contact with the other party. Generally, the Marine Radio has a call button, and when the button is pressed, the ringing tone will sound.
4 button mode: In this mode, the transmit path is closed. If the VOX function is turned on, the MIC part circuit remains on, otherwise it is turned off. The noise detection section is turned on to collect noise information. After the button is pressed, the signal will be sent to the speaker to emit a button tone.