Adaptive silence deletion for speech storage and voice mail applications
Cheong K. Gan, Robert W. Donaldson · IEEE Transactions on Acoustics Speech and Signal Processing · 1988
An algorithm that uses two adaptive-amplitude thresholds and zero-crossing rate was used to delete nonspeech material from speech waveforms which have been digitally encoded and then decoded using PCM, adaptive-differential PCM, and adaptive-delta-modulation. Typically, compression rates of 35% resulted. Subject evaluations are used to assess reconstructed speech quality, which improves significantly when absolute silence on playback is replaced with prerecorded background noise.>