| 摘要 |
PURPOSE:To always transmit the MODEM signals with quality of 64Kb/SPCM (mu/Alaw) regardless of types of the MODEM signals, by performing no ADPCM coding in case an input signal is equal to the MODEM signal to transmit the PCM signal as it is and then performing the ADPCM coding in case the input signal is equal to a voice signal. CONSTITUTION:A voice detector 4 discriminates a significant section from a pause section of an input PCM signal (a) and produces a voice detecting signal (d) to transmit this signal to an asignment processor 8 so that a PCH or an ACH to be transmitted is allocated to an appropriate DSI channel. A data/voice discriminating circuit 5 discriminates the voice band data or voice signals through a filter which monitors the time steadiness of a frequency spectrum and signals for each channel of the signal (a). Then an output signal (e) is sent to PCM/ADPCM selection circuits 61-6m as well as to a processor 8. These section circuits 61X-6m deliver a PCM signal in case the signal (e) is equal to data and then delivers an ADPCM signal with a voice signal and send these signals to a time division multiplexing circuit 7 respectively. |
