| 摘要 |
PROBLEM TO BE SOLVED: To reduce difficulty in hearing caused by background noise by estimating the background noise component as a preprocessing of speech encoding and subtracting the component from an input signals, encoding for transmission, and subtracting the background noise component estimated at the time of the noise suppression from the received and decoded signal. SOLUTION: Background noise superimposed on an input speech signal digitized by an A/D converter 1 is estimated by calculation by a noise estimating unit 3 and subtracted from an input speech signal by a substractor 4, and then, the signal is encoded by a speech encoding part 6 for an output transmission. On the other hand, the calculated estimation noise by the noise estimating unit 3 is subtracted from the digital reception signal decoded in a speech decoding part 7 by a substracter 8, and then, the signal is processed by a D/A converter 9 for outputting the received speech signal. Since the background noise component has already been removed from this received speech output, a listener can hear it easier. |
