| 摘要 |
PROBLEM TO BE SOLVED: To provide a demodulating circuit capable of generating oscillator output suppressed in influence of a phase modulation component included in a video intermediate-frequency signal, and preventing generation of buzz sound in a sound signal to demodulate high-quality sound, and an analog television broadcast receiver.SOLUTION: This demodulating circuit includes: a voltage-controlled oscillator oscillating at a frequency in accordance with a control voltage; a first phase detector for detecting a phase difference between an oscillation signal of the voltage-controlled oscillator and a video intermediate-frequency signal; a second phase detector for detecting the phase difference between the oscillation signal of the voltage-controlled oscillator and the video intermediate-frequency signal; an inverting circuit for inverting polarity of an output signal of the second phase detector; a high-pass filter making only a high-frequency component of the output signal of the inverting circuit pass therethrough; an adder for calculating a sum of the output signal of the first phase detector and the output signal of the high-pass filter; and a loop filter making only a lower-frequency component of the output signal of the adder pass therethrough to feed the control voltage back to the voltage-controlled oscillator. |
