| 摘要 |
PURPOSE:To enable usage of a narrow-band filter as carrier reproduction by adding a phase correction circuit. CONSTITUTION:Partial output S (f1) from the video IF amplifier 21 is supplied to the mixer 23, converted to the IF signal B (f1+ or -f2) by the signal from the local oscillator 22, passed through the narrowband filter 24 and supplied to the phase regulator 27 by suppressing the amplitude element with the limitter 25. On the other hand, frequency F (f1) is selected by the band-pass filter 29 and this signal F (f1) is a supplied to the one side of the input terminal of the mixer 34 through the 90 deg. phse shifter 32 and limiter 29. Output S (f1) from the above-mentioned video IF amplifier system 21 is supplied to the other input terminal of the mixer 34 and the mixed output signal J becomes the signal which complies with the phase difference between the coherent detection signal G (f1) which supplied to the mixer 31 and the carrier of the video signal S (f1). This signal is supplied to the phase regulator 35 as the phase control signal through the low-pass filter 35. |
