| 摘要 |
PURPOSE:To obtain good picture quality without decrease of resolution by preventing deterioration in the frequency band area of a luminance signal when a sound FM signal that is overlapped on a video signal is eliminated. CONSTITUTION:The titled circuit is to cancel and eliminate the sound FM signal by phase-locking the sound FM signal with a PLL (Phase locked Loop) circuit, and performing the subtraction process of the output signal of a VCO (Voltage Controlled, oscillator) phase-locked with the sound FM signal, from a video sound FM composite signal, and to take out a luminance signal having a wide band area without signal deterioration. In other words, after the low-pass component of the video sound FM composite signal is sampled with an LPF5, and by performing the subtraction process of the output signals of VCOs 14 and 17 which oscillate phase-locking with the sound FM signal by a PLL circuit, with a subtractor 18, the sound FM signal is cancelled and eliminated, thereby, the video signal without frequency deterioration can be obtained.
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