Method and system for suppressing communication noise of baseband voice signals

Abstract

The invention discloses a method of suppressing communication noise of baseband voice signals. At a transmitting end, the baseband voice signal band is divided into two sub bands; low pass filter processing and automatic gain control (AGC) constant amplitude processing are carried out on original voice signals, and the obtained signals are transmitted in the low frequency sub band; an original voice signal waveform envelope is extracted during an AGC process, and envelope signals are obtained and are subjected to frequency modulation and are transmitted in the high frequency sub band; during the AGC constant amplitude processing process, voiced-segment signals are subjected to amplitude compression processing and silent-segment signals are subjected to amplitude expansion processing, the signal amplitudes tend to be consistent, and the dynamic range becomes small; at a receiving end, a voice signal envelope is extracted through bandpass filtering and frequency modulation, and according to the envelope, low pass constant amplitude voice signals are subjected to waveform recovery; and the voice waveform recovery is an AGC inverse process. As the silent-segment signals are compressed and the voiced-segment signals are expanded, the silent-segment noise is thoroughly suppressed, the voiced-segment noise is covered by the voice signals, and good voice intelligibility can be obtained.

Description

technical field [0001] The invention relates to a method and system for suppressing communication noise of a baseband voice signal. Background technique [0002] Such as figure 1 As shown, short-wave communication refers to radio communication using electromagnetic waves with a wavelength of 100-10m (frequency 3-30MHz) as a propagation carrier and the atmospheric ionosphere as a relay system. Due to the non-ideality of the communication channel, the short-wave signal will be affected by various distortions such as white noise, multipath effect, and Doppler frequency shift during the propagation process. The signal distortion caused by multipath effect and Doppler frequency shift can be compensated through equalization processing in time domain and frequency domain. The influence of white noise on the signal is usually weakened by filtering technology. However, due to the long-distance propagation of short-wave communication, the superimposed noise of the signal is greater...

AI Technical Summary

Problems solved by technology

After the superimposed noise signal is low-pass filtered, the out-of-band noise in the frequency domain is basically filtered out, but the in-band noise still exists, and the time-domain signal still has large amplitude and phase fluctuations

Since the in-band noise cannot be separated from the speech signal in both the frequency domain and the time domain, this amplitude fluctuation causes the human ear to hear the harsh noise, and the intelligibility of the speech signal is greatly reduced

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