Other

Lucent Technologies Inc.

Thomas John Janiszewski

Michael D Turner

Michael Charles Recchione

A pitch gain of the adaptive codebook portion of a vocoder's encoder is monitored to determine when an instability condition is about to occur by examining a pitch gain value and an averaged pitch gain value. When an instability is likely, the output of a gain control unit is set to an adaptive gain control value. When an instability is unlikely, the gain control unit passes the pitch gain to its output unmodified.

Method for adaptively controlling the pitch gain of a vocoder's adaptive

A method and apparatus for improving sound quality in a digital cellular radio system receiver. A voice activity detector uses an energy estimate to detect the presence of speech in a received speech signal in a noise environment. When no speech is present the system attenuates the signal and inserts low pass filtered white noise. In addition, a set of high pass filters are used to filter the signal based upon the background noise level. This high pass filtering is applied to the signal regardless of whether speech is present. Thus, a combination of signal attenuation with insertion of low pass filtered white noise during periods of non-speech, along with high pass filtering of the signal, improves sound quality when decoding speech which has been encoded in a noisy environment.

Growing community of inventors

Clinton, NJ, United States of America

Thomas John Janiszewski