| 摘要 |
PURPOSE:To realize the increase in a capacity for incoming data while effectively utilizing a line resource. CONSTITUTION:A reference clock signal sent through a CATV network is recovered through a loop comprising a detection circuit 48, an LPF 49, a VCO 50, a 1/4 frequency divider 51, an in-phase detection circuit 44, and an orthogonal detection circuit 45 and used for generating a receiver side carrier. The detection circuit 48 and a symbol conversion circuit 72 recover the sent outgoing data. A transmission side carrier based on the reference clock is generated by a loop comprising a fixed frequency divider 52, a phase comparator circuit 53, an LPF 54, a VCO 55, a 1/4 frequency divider 56, and a fixed frequency divider 57. Modulation circuits 61, 62 and an adder 63 modulate incoming data by using the sender side carrier to provide an output of an incoming modulation wave. |
