The Design Of Focusing On Multi-terminal Call System

Armored command vehicle traveling in the process, the car engine, air conditioner and other equipment will make noise that can measure up to 100dB(A), seriously affecting the call quality, reducing car staff efficiency. How to complete the high-quality call between the car members, between interior and exterior in such high-noise environments, becomes a pressing need.In this background application, the paper designed noise reduction call system focusing on multi-terminal, to make people communicate clearly at 100dB(A) noise environments. Call functions include the following three parts: firstly, armored command vehicle can complete the conference call; secondly, the car member can call radio equipment; thirdly, car members can receive voice messages, at 100dB(A) of the noise environment, Sentence intelligibility above 95%.First proposed the overall design; in noise reduction design, the use of noise reduction and voice endpoint detection. In hardware design, build ARM9 + DSP framework to complete the entire voice system collection, transmission.In software design, in order to complete the audio capture and playback, write DSP voice processing program encoding and decoding; in order to eliminate background noise, use assembly speech for voice endpoint detection algorithm; in order to control intercom system, write Linux applications complete information forwarding, system control; in order to make the car members get vehicle state information, write VC program to transmit the voice information to car members.The system debug. The test results showed that: in a noisy environment, armored command vehicle interior member can complete the conference call; the car can also be done on the external members' point to point radio calls, while occupants can receive voice messages sent by computer. Under 100dB(A) noise environment, call system performance fully meets the requirements of armored command vehicle call.