| 摘要 |
PURPOSE:To transmit all channels of signals of PCM 1st order group by providing a circuit prolonging the sampling period of a PCM signal and a circuit applying inversion. CONSTITUTION:A reception circuit 11 receives the PCM 1st order group signal, a branch circuit 13 branches the signal into voice bits and signaling bits, a digital filter circuit 27 prolongs the sampling period, a PCM-ADPCM converting circuit 15 converts an 8-bit PCM signal into a 4-bit ADPCM signal and multiplexed with a signaling information string from the branch circuit 13 by a multiplex circuit 17. Then the multiplexed signal is inputted to a separation circuit 20 via a transmission circuit 18 and a reception circuit 19. Then the ADPCM signal and the signaling information separated by the separation circuit 20 are inputted to ADPCM-PCM converting circuits 21, 22 and the sampling period of each PCM signal string transmitted respectively from the circuits 21, 22 is shortened by digital filter circuits 29, 30. |
