PRIVATE CATV SYSTEM, UP-CONVERTER AND DOWN-CONVERTER

摘要

PROBLEM TO BE SOLVED: To correctly restore an incoming signal by a down-converter in a built-in CATV system where the incoming signal is converted into a signal by a terminal side up-converter and the signal obtained by frequency-converting the incoming signal by the down-converter is outputted to an external system. SOLUTION: The down-converter 10 is not normally operated sometimes by a high frequency signal for frequency conversion which leaks from the up- converter 20 in a system for transmitting the incoming signal through the the up-converter 20 and the down-converter 10. In this system the up-converter 20 is constituted to converter the frequency of the incoming signal in two stages so that frequency of high frequency signal used for frequency conversion is set to be different for the converters 10 and 20. Thus, the down-converter 10 is normally operated and the incoming signal is transmitted by an external bi-directional CATV system.