JPS5646325A - Electronic tuner - Google Patents

Electronic tuner

Info

Publication number
JPS5646325A
JPS5646325A JP12185179A JP12185179A JPS5646325A JP S5646325 A JPS5646325 A JP S5646325A JP 12185179 A JP12185179 A JP 12185179A JP 12185179 A JP12185179 A JP 12185179A JP S5646325 A JPS5646325 A JP S5646325A
Authority
JP
Japan
Prior art keywords
circuit
output
tuning
pulse width
aft
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
JP12185179A
Other languages
Japanese (ja)
Inventor
Masahiro Fujita
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 JP12185179A priority Critical patent/JPS5646325A/en
Publication of JPS5646325A publication Critical patent/JPS5646325A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J7/00—Automatic frequency control; Automatic scanning over a band of frequencies
    • H03J7/02—Automatic frequency control
    • H03J7/04—Automatic frequency control where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant
    • H03J7/06—Automatic frequency control where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant using counters or frequency dividers

Landscapes

  • Television Receiver Circuits (AREA)
  • Channel Selection Circuits, Automatic Tuning Circuits (AREA)

Abstract

PURPOSE:To increase the stability and reliability of tuning, by providing a malfunction preventing circuit which automatically restricts the operation voltage in failure for the adjusting voltage by the AFT signal at the fine adjustment pulse width tuning circuit. CONSTITUTION:When a channel is selected, the signals AFT-1, AFT-2 of fine tuning shift are detected and they are input to the waveshpae circuit 80. The output of the circuit 80 is input to the malfunction preventing circuit 79 of the fine tuning pulse width modulation circuit 74. The circuit 79 receives the up-down count instruction signal from the circuit 80 to control the UP/DOWN counter circuit 78 and to restrict the operation of the circuit 78 within a given range so that the pulse width of the pulse duty according to the output data of the circuit 78 cannot be varied limitless. The output of the circuit 74 and the output of the coarse adjusting pulse width modulation circuit 71 are added or subtracted at the matrix circuit 72, the output of the circuit 72 passes through the LPF73 and the voltage VT for electronic tuning adjustment is output.
JP12185179A 1979-09-21 1979-09-21 Electronic tuner Pending JPS5646325A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP12185179A JPS5646325A (en) 1979-09-21 1979-09-21 Electronic tuner

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP12185179A JPS5646325A (en) 1979-09-21 1979-09-21 Electronic tuner

Publications (1)

Publication Number Publication Date
JPS5646325A true JPS5646325A (en) 1981-04-27

Family

ID=14821494

Family Applications (1)

Application Number Title Priority Date Filing Date
JP12185179A Pending JPS5646325A (en) 1979-09-21 1979-09-21 Electronic tuner

Country Status (1)

Country Link
JP (1) JPS5646325A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4450587A (en) * 1981-11-27 1984-05-22 Rca Corporation Tuning arrangement for providing relatively uniform automatic fine tuning sensitivity
EP2015557A2 (en) 2007-07-02 2009-01-14 Ricoh Company, Ltd. Optical scanner and image forming apparatus including same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4450587A (en) * 1981-11-27 1984-05-22 Rca Corporation Tuning arrangement for providing relatively uniform automatic fine tuning sensitivity
EP2015557A2 (en) 2007-07-02 2009-01-14 Ricoh Company, Ltd. Optical scanner and image forming apparatus including same

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