| 摘要 |
PROBLEM TO BE SOLVED: To simultaneously receive and reproduce data and sound multiplex- transmitted through the use of a single analog line by subtracting the echo component estimated by an echo estimating part from the received signal of a hybrid circuit and supplying the resultant signal to a receiving part. SOLUTION: A transmitter is provided with a hybrid circuit(HYB) 44, an echo estimating part 56 and an echo removing part (adding part) 58. The circuit 44 sends a transmitted signal from a transmission part 30 to a two-wire analog line and separates a received signal from the two-wire analog line to a receiving part 32. An echo estimating part 56 estimates echo components from the transmitted signal of the part 30. An echo removing part 58 subtracts the echo component estimated by the part 56 from the received signal of the circuit 44 and supplies the resultant signal to the part 32. By removing the echo component included in the received signal, the signal quality in the case of fully duplex using the two-wire analog line as a transmission line can be improved. |
