Voice Squelch Method in Civil Aviation VHF Anti-jamming Transceiver

Abstract

The invention discloses a voice squelch method in a civil aviation VHF anti-jamming transceiver. Firstly, the carrier frequency estimation method based on the Goertzel algorithm is used to judge whether there is a signal or whether the quality is good or bad; The voice detection method distinguishes whether there is a voice signal in the signal; secondly, in conjunction with the AM modulation degree judged in real time by the system, the audio squelch threshold is adaptively adjusted to realize the automatic on-off of the demodulated output voice; the method proposed by the present invention can be used in During normal voice communication, there will no longer be intermittent and some special noises that cannot be turned off, which effectively solves the problem of voice communication quality caused by squelch, and improves the output voice quality level of civil aviation VHF anti-jamming transceivers.

Description

technical field [0001] The invention belongs to the technical field of voice squelch, and in particular relates to a voice squelch method in a civil aviation VHF anti-jamming transceiver. Background technique [0002] Voice squelch means that in voice communication mode, when the SINAD (signal-to-noise and distortion ratio) of the voice signal demodulated by the receiver is very poor, the audio output can be automatically turned off to prevent the noise from being unbearable for the listener. In civil aviation voice communication, when the voice squelch is not handled properly, it is easy to miss or misjudge, and the voice is intermittent, which greatly affects the normal voice communication between pilots and ground controllers, and improves flight safety. bring great danger. [0003] Common squelch methods mainly include pilot squelch, noise detection squelch, audio detection squelch and carrier detection squelch. Among them, pilot squelch refers to controlling squelch b...

AI Technical Summary

Problems solved by technology

Among them, the pilot squelch refers to controlling the squelch by detecting whether there is a pilot signal in the demodulated output signal. Its advantage is that the anti-interference ability is relatively strong, and the disadvantage is that the hardware implementation is more complicated, and at the cost of sacrificing part of the transmit power ; Noise detection squelch is to control the squelch by detecting the noise intensity of the high-frequency part of the voice in the frequency discrimination output signal. Poor; audio detection squelch is to achieve voice squelch by counting the noise characteristics on the demodulated output baseband voice signal, but when the noise signal is large, it is difficult to accurately judge whether to turn off the voice output by relying on the voice energy statistics alone; Carrier squelch controls the squelch by detecting the carrier strength of the received RF signal. Generally, the carrier phase-locked loop is used to extract the carrier, and whether to turn off the voice output is determined by judging whether the loop output carrier statistics value is greater than the threshold. The implementation of the method is relatively simple, but it is easy to misjudgment when there is a carrier but no voice. At the same time, because the statistical characteristics of the AM modulation mode have a certain relationship with the change of the modulation degree, it is difficult to determine a suitable carrier threshold in practical applications.

Images