Receiving device of multi-channel CATV system and multi-channel CATV system

摘要

PURPOSE: To provide a multiple channel CATV system and the receiver of the multiple channel CATV system for efficiently processing transmission signals and improving the consistency of an equipment with an existing satellite broadcast indoor receiver. ;CONSTITUTION: The television transmission signals 6 of multiple channels from a transmitter 1 are the mixture of three signals of a low frequency group A3a, an intermediate frequency group B3b and a high frequency group C3c. Positive polarity frequency modulation for which the rise of luminance corresponds to the rise of a carrier frequency is defined for the signals of the intermediate frequency group of the transmission signals 6 and negative polarity frequency modulation for which the rise of the luminance corresponds to the fall of the carrier frequency is defined for the signals of the low frequency group and the high frequency group. Also, in the receivers 7 and 8, reception signals 6 are divided into the three frequency band signals by using filters 9, 10 and 11. Frequency conversion to an intermediate frequency band and one step of modulation polarity inversion are performed for the divided signals of the low frequency group 3a and the high frequency group 3c and the demodulation of FM signals is executed. The frequency conversion is not performed for the signals of the intermediate frequency group B3b.;COPYRIGHT: (C)1995,JPO