| 摘要 |
PURPOSE:To perform a simultaneous transmission of both the voice and data, by retarding the transmitting speed of a voice signal at a high frequency band among voice frequency bands, and allotting the retarded speed of transmission to the transmission of the data signal. CONSTITUTION:The voice signal of a subscriber 9 is fed to an LPF11 and a BPF13 respectively. The LPF11 cuts the frequency bands (2k-4kHz) which do not affect so much the articulation of the voice, and then delivers the voice signal to a coder 12. The coder 12 performs the sampling and coding with 4kHz and 8 bits and delivers the signal to a timing circuit 17. The BPF13 extracts the frequency bands (2k-4kHz) and delivers the voice signal to a modulator 14. The output of the modulator 14 is applied to an LPF15. The LPF15 extracts the signals of 0-2kHz and delivers them to a coder 16. The coder 16 performs the sampling and coding with 4kHz and 4 bits and delivers the signal to the circuit 17. The circuit 17 transmits the signal sent from a data terminal 10 and the signals of coders 12 and 16 via a hybrid circuit 27 and a switchboard 28. |
