PURPOSE: To eliminate evil influence upon the in-use frequency band of a television signal, FM broadcast signal, etc. by extracting a pilot signal which is frequency-converted to a frequency band other than said in-use frequency band through a BPF.
CONSTITUTION: A pilot signal extracted by a directional coupler 4 is converted to a frequency band other than the in-use frequency band used by a television signal, FM broadcast signal, etc., and the frequency-converted pilot signal is extracted through the BPF5. Consequently, there is no evil influence upon the in-use frequency band of the television signal, FM broadcast signal, etc., even if there is a bounce from a stopping frequency band to a passing frequency band when the signal is passed through the BPF.
TAGAWA AKIRA
FUKUOKA HIROYUKI
