| 摘要 |
PURPOSE: To reduce incompatibility in a sound output from a decoder which is generated due to the peripheral change of a background noise transmitted at the time of detecting silence in the VOX (or VAD) processing of a mobile station in respect to a voice coding device to be used for a digital mobile communication type automobile telephone system or the like. CONSTITUTION: The voice coding device is provided with a power controller 14 for inputting VOX mode information, quantized power 4a and a sound signal 13a outputted from a post filter 13, averaging the quantized power 4a for a long time at the occurance of a background noise in a silence section and controlling the power of the sound signal 13a outputted from the filter 13 at the long-time averaged power, the post filter 13 for inputting the VOX mode information and controlling the information so as not to apply filtering processing when a background noise is generated in the silence section and an adaptive code signal decoder 8 for inputting the VOX mode information, switching an adaptive code index 2b inputted at the occurance of the background noise in the silence section to a fixed index and outputting an adaptive code vector signal 8a. |
