| 摘要 |
PURPOSE:To apply the titled system to a long-distance transmission, such as a statellite communication, and making a transmission on a line in the same band available efficiently, by transmitting a video signal and a data signal simultaneously via the same transmission line. CONSTITUTION:A video signal is inputted to a video-signal input terminal 11 and divided into two; one is applied to a synchronous separating circuit 21, and the other to an adding circuit 27. The circuit 21 extracts a horizontal synchronizing signal, which is inputted to a bit-synchronous generating circuit 22 and a PN signal generating circuit 23. A data signal applied to a data-signal input terminal 12 is read via a data buffer memory 24 to a reading circuit 25 by a bit-synchronizing signal from the circuit 22, and modulated by a modulating circuit 26 of spectrum diffusion system with a PN signal from the circuit 23; and it is mixed with a composite signal by the circuit 27 and the resulting signal is outputted to a transmission line. Then, the signal is received by a reception-side circuit provided with a synchronous separating circuit 31, a bit-synchronous generating circuit 32, a PN signal generating circuit 33, a demodulating circuit 34 of spectrum diffusion mode, etc., thereby making the transmission on the line in the same band available efficiently. |
