公开(公告)号：JPS61173596A

公开(公告)日：1986-08-05

申请号：JP1400885

申请日：1985-01-28

Applicant: SONY CORP

Inventor： OSADA YASUO ,  YAMAMOTO TSUGUO ,  MITA HIROYUKI

IPC: H04N7/20 ,  H04B7/185

Abstract: PURPOSE:To receive an image of high quality having a small black-and-white noise by an SHF receiving device for satellite broadcasting by controlling the gain of a gain control amplifier with the output signal of a DC offset circuit and controlling the noise band with of a PLL circuit. CONSTITUTION:An FM signal supplied to an input terminal appears at the output side of a PLL constituting the closed loop of a phase comparator 2, a loop filter 3, a gain control amplifier 4, and a voltage-controlled oscillator 10 as a phase-detected video signal. In this case, the signal is supplied from the output side of the PLL to the control signal generating circuit composed of a band-pass filter 6 of 3.58+ or -0.5MHz, and AM detector 7, a DC amplifier 8, and a DC offset circuit and a control signal is supplied to the gain control circuit 4 as a signal which controls its gain; and a demodulated signal (base band signal) is so controlled as to increase when the level of a chrominance subcarrier of 3.58MHz is large and decreases when the chrominance subcarrier is small in level, thereby varying the equivalent noise band width B1 of the PLL circuit.

公开(公告)号：JPH0681314B2

公开(公告)日：1994-10-12

申请号：JP1400885

申请日：1985-01-28

Applicant: SONY CORP

Inventor： OSADA YASUO ,  YAMAMOTO TSUGUO ,  MITA HIROYUKI

IPC: H04N7/20 ,  H04B7/185

公开(公告)号：JPH0618292B2

公开(公告)日：1994-03-09

申请号：JP3194884

申请日：1984-02-21

Applicant: SONY CORP

Inventor： OSADA YASUO ,  TSURUMARU SHINOBU ,  YAMAMOTO TSUGUO

IPC: H03D3/00 ,  H03D3/06

公开(公告)号：JPS60176310A

公开(公告)日：1985-09-10

申请号：JP3194884

申请日：1984-02-21

Applicant: SONY CORP

Inventor： OSADA YASUO ,  TSURUMARU SHINOBU ,  YAMAMOTO TSUGUO

IPC: H03D3/00 ,  H03D3/06

Abstract: PURPOSE:To make higher a load impedance of a filter in a high band, and to improve a selectivity characteristic in the high band, too, by supplying a passing output of a tracking filter to a phase comparator through a coil for constituting a 90 deg. phase shifter. CONSTITUTION:An FM signal SFM inputted from an input terminal 37 is supplied to a tracking filter 39 through a limiter 38. This filter 39 is constituted of a single tuned amplifier circuit having a steep single peak response, a tuning frequency is changed, also a phase characteristic is varied linearly in the vicinity of the tuning frequency, and it is + or -90 deg. in the outside of the band. An output SFM' of this filter 39 is supplied to a 90 deg. phase shifter 40 constituted of a coil, and inputted to one input terminal of a phase comparator 41. As for this phase comparator 41, that which has a low input impedance is used so that it can be driven enough in the high band. Also, the output SFM of the limiter 38 is inputted to the other input terminal of the phase comparator 41.