PURPOSE: To suppress a leakage of a local oscillation signal from an input terminal in the input circuit of the BS tuner selecting and receiving a 1st intermediate frequency of a satellite broadcast.
CONSTITUTION: A series resonance circuit comprising a very small inductor 4 and a very small capacitor 5 is arranged between an earth and a connecting point between an input terminal 1 of a BS tuner and an input filter 2. Thus, a local oscillation signal invaded directly or indirectly to the input terminal 1 or the input filter 2 is suppressed for a local oscillation frequency band in which a leakage level is most increased and a leakage of the local oscillation signal travelled, through a signal path, which is not sufficiently attenuated only a reverse direction transmission characteristic of a broad band amplifier 3 is simultaneously suppressed.
SUGANUMA MASAHIKO
UMEMURA YOSHIHARU
YOKOUCHI KATSUMASA
HITACHI VIDEO & INF SYST