VERBESSERUNG BEI ECHOWIEDERKEHRVERLUSTEN

摘要

A communications transceiver, such as a GSM mobile, is provided, for communicating in frames of encoded audio, comprising an audio input path (10), an audio output path (22), a voice activity detector (VAD 12) for detecting voice on the audio input path, and echo detecting means (25, 26, 27,13, 28) for detecting unwanted echos on the input path resulting from acoustic coupling with the output path. Transmission of encoded audio from the audio input path is inhibited, by means (14, 29), in the presence of voice which is indicated as echo by the echo detecting means. The transceiver preferably has means for generating silence indicator (SID) frames in place of audio frames during periods of detected echo and means (40) Fig. 4 (not shown) for supplementing the silence indicator (SID) frames with comfort noise parameters and transmitting the supplemented frames for decoding as audio frames at a receiver.