JPS5715537A - Automatic frequency band adjusting circuit - Google Patents

Automatic frequency band adjusting circuit

Info

Publication number
JPS5715537A
JPS5715537A JP9042480A JP9042480A JPS5715537A JP S5715537 A JPS5715537 A JP S5715537A JP 9042480 A JP9042480 A JP 9042480A JP 9042480 A JP9042480 A JP 9042480A JP S5715537 A JPS5715537 A JP S5715537A
Authority
JP
Japan
Prior art keywords
circuit
video
intermediate frequency
inputted
detection
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP9042480A
Other languages
Japanese (ja)
Inventor
Takaoki Ooumaya
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toshiba Corp
Original Assignee
Toshiba Corp
Tokyo Shibaura Electric Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toshiba Corp, Tokyo Shibaura Electric Co Ltd filed Critical Toshiba Corp
Priority to JP9042480A priority Critical patent/JPS5715537A/en
Publication of JPS5715537A publication Critical patent/JPS5715537A/en
Pending legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03JTUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J7/00Automatic frequency control; Automatic scanning over a band of frequencies
    • H03J7/02Automatic frequency control

Landscapes

  • Circuits Of Receivers In General (AREA)
  • Television Receiver Circuits (AREA)

Abstract

PURPOSE:To adjust the overall band characteristics from an antenna terminal to a detection circuit, by controlling the local oscillating frequency of a tuner, through the use of an automatic gain control voltage of a video intermediate frequency processing circuit. CONSTITUTION:A signal introduced to an antenna terminal 11 is selected for channel with a tuner 12 and inputted to a video intermediate frequency processing circuit 13, where the said signal via a preamplifier 14 and a BPF15 at first is inputted to an intermediate frequency amplification and a video detection circuit 16, and the video intermediate frequency is introduced to a ratio detection section 20. The composite video signal in video detection is introduced to an output terminal 17 and inputted to an AGC circuit 18. Further, when the antenna input electric field is lower, if it exceeds the threshold level of a DC voltage converting circuit 29, the terminal voltage of a varactor diode 23 is changed and the tuning point of the detection section 20 is shifted. Thus, since the band of an AFC circuit 21 is narrowed, antinoise performance at weak electric field can be increased.
JP9042480A 1980-07-02 1980-07-02 Automatic frequency band adjusting circuit Pending JPS5715537A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP9042480A JPS5715537A (en) 1980-07-02 1980-07-02 Automatic frequency band adjusting circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9042480A JPS5715537A (en) 1980-07-02 1980-07-02 Automatic frequency band adjusting circuit

Publications (1)

Publication Number Publication Date
JPS5715537A true JPS5715537A (en) 1982-01-26

Family

ID=13998217

Family Applications (1)

Application Number Title Priority Date Filing Date
JP9042480A Pending JPS5715537A (en) 1980-07-02 1980-07-02 Automatic frequency band adjusting circuit

Country Status (1)

Country Link
JP (1) JPS5715537A (en)

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