| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high purity video carrier from an amplitude modulated broadcast radio wave without taking a time and labor in the input level control of a video IF signal. SOLUTION: A carrier extracting section 77a constituting an offset beat canceller and extracting the carrier component from a video IF signal comprises a circuit 91 for amplifying an input signal, and a capacitor 93 for limiting fluctuation in the amplitude of an output signal from the amplifier circuit 91 is connected in series with a pair of diodes 92a, b for grounding the output of the amplifier circuit 91. Since the fluctuation in the amplitude of the output signal from the amplifier circuit 91 can be limited by the capacitor 93 connected in series with the pair of diodes 92a, b, carrier extraction accuracy can be improved. The offset canceller can remove jamming wave components well. COPYRIGHT: (C)2005,JPO&NCIPI
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