DOWN-CONVERTER AND UP-CONVERTER FOR INTERACTIVE CATV SYSTEM AND IN-BUILDING TRANSMISSION SYSTEM FOR MULTIPLE DWELLING HOUSE

摘要

PROBLEM TO BE SOLVED: To obtain an interactive CATV system for a multiple dwelling house in which an upward signal with superimposed noise is hardly transmitted. ;SOLUTION: A transmission system where an upward signal in a building for a multiple dwelling house uses a high frequency band (650 MHz or over) to which a confluent noise is less intruded for the upward signal band, is provided with an up-converter 20 that converts an upward signal frequency (10-50 MHz) for a MODEM 13d into a high frequency and with a down-converter 10 that coverts the high frequency for in-building transmission into a low frequency in matching with an incoming signal band (usually 10-50 MHz) for a CATV truck line. A reference signal based on an oscillation output of a local oscillator built in the down-converter 10 is transmitted to each up-converter via an in-building transmission line and each converter uses a local oscillation signal based on an output of the same local oscillator to conduct frequency conversion.;COPYRIGHT: (C)2000,JPO