| 摘要 |
PURPOSE:To simplify the constitution of transmission/reception circuit and to make the size small in comparison with the case with using a special CODEC and a speed converter by using part of bits as synchronizing bits and sending the synchronizing bits while a synchronizing signal is inserted for each prescribed bit unit of a digitized voice band signal. CONSTITUTION:When a voice signal is inputted in a transmission circuit, a PCM coder 11 adopts the conventional PCM system to convert the signal into a digital signal of one sample 8-bit constitution and outputted as a digital signal string in 64kbps. Then the digitized voice signal outputted from the PCM coder 12 is introduced to a synchronizing signal insertion circuit 12, where the synchronizing signal F is inserted to the low-order LSB bit for each 8-bit and then sent to an auxiliary transmission line. Thus, it is not required to lower the bit rate of the digitized voice signal and to provide a bit for synchronizing signal insertion separately, and the constitution of the transmission circuit and the reception is simplified and miniaturized in comparison with a conventional system. |
