| 摘要 |
PCT No. PCT/IB94/00285 Sec. 371 Date Jul. 20, 1995 Sec. 102(e) Date Jul. 20, 1995 PCT Filed Aug. 11, 1994 PCT Pub. No. WO95/06382 PCT Pub. Date Mar. 2, 1995A voice activity detector is described suitable for use in an echo suppressor. It comprises a whitening filter (19) for levelling the spectrum of the audio signal on the transmit path to provide a levelled signal and decision means (20) coupled to the whitening filter to measure energy in the levelled signal and thereby to detect voice on the transmit path. The whitening filter is a voice whitening filter which is adapted (8, 19) according to the voice parameters received by the voice decoder in the receive path. In a second aspect, a near-end voice entered into the transmit path is distinguished from a far-end voice resulting from an echo from the receive path and transmit and receive attenuators (26, 27) are arranged in a first disposition when voice on the transmit path is substantially due to echo from the receive path and in a second disposition when voice on the transmit path is at least partially due to near-end voice. |
