CHANNEL VIEWING CIRCUIT FOR DISTINGUISHING BETWEEN SIGNAL EXISTENCE AND NON-EXISTENCE IN A SATELLITE BROADCASTING RECEIVER

摘要

A circuit for distinguishing the existence or non-existence of a signal at a satellite-broadcast receiver. The circuit includes an antenna adjusting part aimed toward the satellite after the satellite signal is tuned using a channel tuning stage driven by the output of a microcomputer. The level of the IF signal is detected by the IF signal AGC amplifier and the IF signal level detector. A video signal detecting stage detects the FM signal of the IF signal AGC amplifier output and the existence or nonexistence of the video signal is determined after audio/video signal processsing, and a channel displaying means, wherein the state of said video detecting part and the antenna position where video signal exists are displayed by on-sceen operations.