Digital squelch method

Abstract

The invention relates to squelch technology and discloses a new digital squelch method aiming at the defect in traditional squelch technology. The method can reduce the cost of squelch, improve the reliability of squelch and realize accurate squelch. The technical scheme is mainly characterized by comprising the following steps: setting an intermediate frequency squelch threshold value and an intermediate frequency carrier-to-noise ratio, and comparing to judge whether an intermediate frequency signal exists or not and the signal strength if the intermediate frequency signal exists; setting an audio frequency squelch threshold value and an audio frequency carrier-to-noise ratio, and comparing to judge whether an audio frequency signal exists or not and the signal strength if the audio frequency signal exists; and combing the judgment results of intermediate frequency squelch and audio frequency squelch to judge the quality of voice signal and to determine whether to carry out the squelch process. The digital squelch method provided by the invention is suitable for the squelch process of voice communication equipment.

Description

technical field [0001] The invention relates to squelch technology, in particular to a digital squelch method. Background technique [0002] For wireless voice communication equipment, when the signal-to-noise ratio of the demodulated voice at the receiving end is very poor and the voice intelligibility is very low, the noise will make the listener unbearable. At this time, it is necessary to use squelch technology to turn off the voice. If the voice squelch is not properly designed, the voice output by the receiving end will be intermittent, or when the voice intelligibility is very low, the voice output is not turned off, or when the voice intelligibility is high, The voice output is turned off instead, so the voice squelch technology is a key technology in voice communication. [0003] The squelch techniques in the prior art are roughly divided into three categories: pilot squelch, noise squelch, and carrier detection squelch. The three types of squelch techniques can be...

AI Technical Summary

Problems solved by technology

[0004] The above three squelch techniques all have defects: 1. For the pilot squelch, its hardware circuit is the most complicated, and before the receiver audio amplifier drives the earphones, in order to filter out the pilot, it is necessary to use a relatively expensive bandpass The cost of the filter is very high. In addition, because the pilot signal is added at the sending end, the additional transmission power of the device is increased; 2. For noise squelch, at the receiving end, when the input RF signal is near the threshold , the noise output amplitude curve just turns and is not linear. If the receiver sensitivity is just around this threshold value, it is difficult to debug the noise squelch circuit, and it is difficult to compromise between the squelch opening level and the hysteresis depth. In other words, it is necessary to adjust the squelch potentiometer of the panel several times, otherwise it is easy to fail to receive signals or squelch or appear intermittent; 3. For carrier detection squelch, because it is only The carrier signal is detected, so this method cannot identify the case where there is a carrier but no voice signal

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