| 摘要 |
PURPOSE:To simplify the circuit scale of the channel selection device provided corresponding to each subscriber even in the case of a repeater for a demand access system CATV or the like by adopting the configuration such that an address is given to each of plural PLL circuits and data of a channel request signal received by each PLL circuit are received through a common signal line. CONSTITUTION:A channel request signal from a subscriber is inputted to a channel request signal input terminal 22 and converted into a signal controlling changeover circuits 1-4 at a channel request signal decode circuit 21 and a signal controlling an oscillating frequency of variable local oscillators 13-16, and outputted respectively to conversion circuits 1-4 and PLL circuits 17-20, by which channel selection is implemented. Circuits controlling address designation and a frequency division ratio through a serial control bus are used for the PLL circuits 17-20 and an oscillation signal from a reference oscillator 23 is used in common by the four PLL circuits 17-20. The address as to the PLL circuit required for control is designated to send the data. |
