JPS57150235A - Tuning filter controlling system - Google Patents

Tuning filter controlling system

Info

Publication number
JPS57150235A
JPS57150235A JP3603981A JP3603981A JPS57150235A JP S57150235 A JPS57150235 A JP S57150235A JP 3603981 A JP3603981 A JP 3603981A JP 3603981 A JP3603981 A JP 3603981A JP S57150235 A JPS57150235 A JP S57150235A
Authority
JP
Japan
Prior art keywords
filter
tuning filter
output
voltage
tuning
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
JP3603981A
Other languages
Japanese (ja)
Inventor
Masuo Kobayashi
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.)
Fujitsu Ltd
Original Assignee
Fujitsu 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 Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to JP3603981A priority Critical patent/JPS57150235A/en
Publication of JPS57150235A publication Critical patent/JPS57150235A/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

Landscapes

  • Noise Elimination (AREA)

Abstract

PURPOSE:To minimize insertion loss of a filter, by executing fine adjustment of control voltage of a spurious removing filter by use of detection voltage which has detected an output of the filter. CONSTITUTION:When radio frequency is decided by a synthesizer 2, its frequency information is transferred to a D/A converting circuit 4, and by this output voltage, the center frequency of a tuning filter 3 is decided. On the other hand, an output from the tuning filter 3 is branched, is detected by a detecting circuit 7, and is inputted to a differential amplifier 9 and a voltage holding circuit 8. In this case, it is compared with the previous output of the tuning filter 3, which is held by the voltage holding circuit 8, by a differential amplifier 9, the output voltage of the D/A converting circuit 4 is increased or decreased so that the insertion loss of the tuning filter 3 is minimized, and the center frequency of the tuning filter 3 is adjusted.
JP3603981A 1981-03-13 1981-03-13 Tuning filter controlling system Pending JPS57150235A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3603981A JPS57150235A (en) 1981-03-13 1981-03-13 Tuning filter controlling system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3603981A JPS57150235A (en) 1981-03-13 1981-03-13 Tuning filter controlling system

Publications (1)

Publication Number Publication Date
JPS57150235A true JPS57150235A (en) 1982-09-17

Family

ID=12458559

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3603981A Pending JPS57150235A (en) 1981-03-13 1981-03-13 Tuning filter controlling system

Country Status (1)

Country Link
JP (1) JPS57150235A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63142726A (en) * 1986-12-04 1988-06-15 Japan Radio Co Ltd Receiver
US4995368A (en) * 1988-02-04 1991-02-26 Nippondenso Co., Ltd. Fuel injection timing apparatus

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63142726A (en) * 1986-12-04 1988-06-15 Japan Radio Co Ltd Receiver
JPH0420533B2 (en) * 1986-12-04 1992-04-03 Japan Radio Co Ltd
US4995368A (en) * 1988-02-04 1991-02-26 Nippondenso Co., Ltd. Fuel injection timing apparatus

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