JPS5920766U

JPS5920766U - Video synchronous detection device

Info

Publication number: JPS5920766U
Application number: JP11487382U
Authority: JP
Inventors: 椛沢　仁
Original assignee: 株式会社東芝
Priority date: 1982-07-30
Filing date: 1982-07-30
Publication date: 1984-02-08

Abstract

(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Brief explanation of drawings]

第１図は従来の映像同期検波装置を示すブロン・り図、
第２図は本考案に係る映像同期検波装置を示すブロック
図、第３図は第１図及び第２図に示す狭帯域バンド争パ
ス・フィルタの振幅特性及び位相特性を示す周波数特性
図、第４図は第２図に示す位相検波回路の周波数対出力
電圧の関係を示す特性図、第５図は位相検波回路の一例
を示す回路図、第６図はチューナにシンセサイザ方式を
用いた場合、チューナの局部発振周波数を制御するため
の制御回路の一例を示すブロック図である。２・・・チュー力、３・・・映像中間周波フィルタ、４
・・・掛算形検波器、５・・・狭帯域バンド・パス・フ
ィル、夕、６・・・出力端子、７・・・位相検波回路。第５図第６図Figure 1 is a block diagram showing a conventional video synchronous detection device.
FIG. 2 is a block diagram showing the video coherent detection device according to the present invention, FIG. 3 is a frequency characteristic diagram showing the amplitude and phase characteristics of the narrow band contention pass filter shown in FIGS. 1 and 2; Figure 4 is a characteristic diagram showing the relationship between frequency and output voltage of the phase detection circuit shown in Figure 2, Figure 5 is a circuit diagram showing an example of the phase detection circuit, and Figure 6 is a diagram showing the relationship between the frequency and the output voltage of the phase detection circuit shown in Figure 2. FIG. 2 is a block diagram showing an example of a control circuit for controlling the local oscillation frequency of the tuner. 2... Chu force, 3... Video intermediate frequency filter, 4
. . . Multiplying type detector, 5 . . . Narrowband band pass filter, 6 . . . Output terminal, 7 . . . Phase detection circuit. Figure 5 Figure 6

Claims

[Scope of utility model registration request]

A tuner that can control the local oscillation frequency, a video intermediate frequency amplification stage that selects a video intermediate frequency signal frequency-converted by the tuner, and a narrow band that extracts a video carrier signal from the video intermediate frequency signal output from the tuner. a band pass filter, a detection circuit that performs synchronous detection by multiplying the video intermediate frequency signal from the amplification stage and the video carrier signal, and an input signal and an output signal of the narrowband band pass filter; It is characterized by comprising a phase detection circuit that detects a phase difference and controls the local oscillation frequency of the tuner using the detection output, and inputs a constant frequency signal to the narrowband Basidic pass filter. Video synchronous detection device.