| 摘要 |
PURPOSE:To attain ease of timing recovery/locking without much hardware of an echo canceller by transmitting a frame pulse, a training pulse and a transmission data in this order from the master side, applying timing recovery/ locking during the training pulse reception period at the slave side and inhibiting the transmission of a signal until the end of the training pulse reception. CONSTITUTION:A control circuit 6 controls a selector 3 to select a frame pulse FP from a frame pulse generator 1, a training pulse TP from a training pulse generator 2 and a transmission data DSI at the master side during one frame period T. Further, a period Td when no signal is transmitted is provided, a U/B converter 4 converts a signal into a bipolar signal and the result is transmitted to the slave side via a hybrid circuit 5. The transmitted signal is received via a hybrid circuit 16, a control circuit 19 controls a timing recovery circuit 20 for timing recovery during the training pulse period, and the frame pulse FP and a transmission data DS2 are selected and transmitted. |
