Pulse or digital communications – Bandwidth reduction or expansion – Pulse code modulation
Patent
1994-12-02
1995-12-12
Chin, Stephen
Pulse or digital communications
Bandwidth reduction or expansion
Pulse code modulation
381 36, 395 228, 395 232, 455281, H04B 110
Patent
active
054757126
ABSTRACT:
A low-delay code excited linear prediction (LD-CELP) voice coding systemapplied to a scheme, in which the transmitting side interrupts transmission during the voice-nonactive period and the receiving side generates and outputs a comfort noise during the voice-nonactive period. At the transmitting side, when voice non activity is detected by the voice activity detector, the CN flag indicating the interruption of transmission is sent from the CN flag generator and shortly thereafter a background noise from the LD-CELP encoder is sent, followed by the interruption of transmission. At the receiving side, when the background noise following the CN flag is decoded by the LD-CELP decoder, the internal gain and synthesis filter coefficients are held, which is subsequently used to decode the input from the pseudo-noise generator.
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Chin Stephen
Kokusai Electric Co. Ltd.
Lobato Emmanuel J.
Webster Bryan
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