JPS5920765U

JPS5920765U - Video synchronous detection device

Info

Publication number: JPS5920765U
Application number: JP11487282U
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ック図、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２図に示す狭帯域ハンド・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図は位相検波回路に用いられる具体的
な回路を示す回路図、第６図は発振器に用いられる具体
的な回路を示す回路図である。、２・・・チューナ、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・
フィルタ、６・・・出力端子、７．８・・・混合回路、
９・・・位相回路、１０・・・位相検波回路、１１・・
・発振器。FIG. 1 is a block diagram showing a conventional video coherent detection device, FIG. 2 is a block diagram showing a video coherent detection device according to the present invention, and FIG. 3 shows the amplitude of the narrowband hand pass filter shown in FIG. 2. A frequency characteristic diagram showing the characteristics and phase characteristics, Fig. 4 is a characteristic diagram showing the relationship between frequency and output voltage of the phase detection circuit shown in Fig. 2, and Fig. 5 shows a specific circuit used in the phase detection circuit. Circuit Diagram FIG. 6 is a circuit diagram showing a specific circuit used in the oscillator. , 2... Tuner, 3... Video intermediate frequency filter,
4... Multiplying type detector, 5... Narrowband band pass.
Filter, 6... Output terminal, 7.8... Mixing circuit,
9... Phase circuit, 10... Phase detection circuit, 11...
・Oscillator.

Claims

[Scope of utility model registration request]

a video intermediate frequency amplification stage that selects the video intermediate frequency signal frequency-converted by the tuner; a first mixing circuit that frequency-converts the video intermediate frequency signal output from this amplification stage; a narrowband band pass filter that passes the video carrier signal from the converted signal; a second mixing circuit that frequency-converts the output of this filter into the video intermediate frequency signal; and an oscillation signal to the first and second mixing circuits. and a phase adjusted so that the frequency of the converted signal frequency-converted by the first mixing circuit has a phase difference of 90 degrees with respect to the band center frequency of the narrow band band pass filter. a phase detection circuit that detects a phase difference between the output signal of the phase circuit and the output signal of the narrowband band pass filter and controls the oscillation frequency of the oscillation circuit using the detection output; and a detection circuit that performs synchronous detection by multiplying the output signal of the mixing circuit by the video intermediate frequency signal, and inputs a constant frequency signal to the narrowband band pass filter. Video synchronous detection device.