| 摘要 |
PURPOSE:To apply a semi-duplex synchronizing system MODEM to a communication system of subsequent synchronizing system by providing a pilot signal generating section for subsequent synchronizing timing recovery, a pilot signal extraction section and a timing recovery section. CONSTITUTION:In sending a data from a MODEM 20 to a MODEM 19, a pilot signal generating section 2 and a demodulation section 6 in the MODEM 20 are operated by the control of a control section 1. A modulation section 3 of the MODEM 19 is operated by the control of the control section l, and a pilot signal is outputted from a pilot signal generation section 2 of the MODEM 19 via a hybrid circuit 5 to a two-wire voice line 9. A pilot signal extracting section 7 of the MODEM 20 extracts a pilot signal from the signal inputted from the two-wire voice line 9 via the hybrid circuit 5, a timing recovery section 8 recovers the subsequent synchronizing transmission timing from the pilot signal and outputs the result to the modulation section 3. Then the modulation section 3 sends a signal synchronized with the subsequent synchronizing transmission timing by the control of the control section 1. |
