Airborne Digital Stereo Noise Reduction Technology

In the strong noise onboard especially rotary wing helicopter, rotor air flow generated noise is important factors of human effectiveness, on the other hand due to radio noise and interworking of microphone noise also affected the pilot comfort. Anti-noise technology research and development of voice processing systems is a very important content, in various fields have broad application. However in the airborne sound system, due to particularities and restrictions on the use of the application, airborne audio noise reduction has always been seen by industry concern. The issue of carrier aircraft noise environment, the mainstream speech enhancement algorithm simulation for on-board to assess the effect of strong noise rejection, and build real-time processing platform, the algorithm shift value. According to the subject of applied research, this article outlines the noise reduction in digital audio technology, involving speech enhancement and noise suppression associated with the fundamental principles, including strong voice without background noise detection algorithm VAD, adaptive noise suppression algorithm ANS, adaptive echo cancellation algorithm AEC, and dual-channel speech enhancement algorithm ANC. Text is given in a variety of algorithms for MATLAB simulation results, designing airborne digital integrated processing system and use of relevant data gives the combined effect of VAD, ANS and ANC algorithm.The subject's main research contents are as follows:1. For the airborne sound application in radio station and around the cabin intercommunication microphone noise, are calculated by using the spectrum changes in the size of the voice detection algorithm in VAD, in the strong background noise, the situation of low SNR, a segment and segment can also be accurately separated, improve the voice ear comfort.2. For traditional airborne simulation system reflects the strong howling, the adaptive echo cancellation technology is studied, and fundamentally eliminates the simulation of sound whistle the physical foundation, achieve the howling suppression index. 3. For the environment has a segment of the noisy speech, the adaptive noise suppression algorithm ANS, dual channel speech enhancement algorithm of ANC were studied, in strong background noise can be effectively improved by the audible speech intelligibility.4. Construction of real-time processing platform, the development of digital voice processing system, the algorithm is to shift the value of using relevant data are given in airborne environment digital voice system integrated noise reduction effect.