JPS57171808A - Fm demodulating circuit - Google Patents

Fm demodulating circuit

Info

Publication number
JPS57171808A
JPS57171808A JP5739981A JP5739981A JPS57171808A JP S57171808 A JPS57171808 A JP S57171808A JP 5739981 A JP5739981 A JP 5739981A JP 5739981 A JP5739981 A JP 5739981A JP S57171808 A JPS57171808 A JP S57171808A
Authority
JP
Japan
Prior art keywords
supplied
filter
voltage
output
signal
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
JP5739981A
Other languages
Japanese (ja)
Inventor
Tsuneaki Matoba
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.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
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 Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to JP5739981A priority Critical patent/JPS57171808A/en
Publication of JPS57171808A publication Critical patent/JPS57171808A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D3/00—Demodulation of angle-, frequency- or phase- modulated oscillations
    • H03D3/02—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal
    • H03D3/24—Modifications of demodulators to reject or remove amplitude variations by means of locked-in oscillator circuits
    • H03D3/241—Modifications of demodulators to reject or remove amplitude variations by means of locked-in oscillator circuits the oscillator being part of a phase locked loop

Abstract

PURPOSE:To improve a threshold level by decreasing a range of synchronism in a weak electric field by applying a control voltage, which corresponds to an input electric field level, to the loop filter of an FM demodulating circuit with a phase synchronizing loop. CONSTITUTION:An FM intermediate frequency signal is supplied to an input terminal 1 and then inputted to a PLL demodulating circuit 7, consisting of a phase comparator 4, a loop filter 5, and a voltage-controlled oscillator 6, through an IF filter 2 and an IF amplifier 3. A signal inputted to the comparator 4 is compared with the output of the oscillator 6 and its comparison output is supplied to the terminal 20 of the filter 5. A signal supplied from the amplifier 3 to a control part 9 is detected and converted into a DC signal, which is supplied to the terminal 22 of the filter 5 as a voltage which corresponds to an electric field level. A distortion component extracted from the output of the filter 5 through an HPF11 is supplied to a control part 10 and a DC voltage which corresponds to the level is supplied to the filter 5 similarly. The output of an operational amplifier 15 is supplied to the oscillator 6 through a BPF23.
JP5739981A 1981-04-15 1981-04-15 Fm demodulating circuit Pending JPS57171808A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP5739981A JPS57171808A (en) 1981-04-15 1981-04-15 Fm demodulating circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP5739981A JPS57171808A (en) 1981-04-15 1981-04-15 Fm demodulating circuit

Publications (1)

Publication Number Publication Date
JPS57171808A true JPS57171808A (en) 1982-10-22

Family

ID=13054554

Family Applications (1)

Application Number Title Priority Date Filing Date
JP5739981A Pending JPS57171808A (en) 1981-04-15 1981-04-15 Fm demodulating circuit

Country Status (1)

Country Link
JP (1) JPS57171808A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2564663A1 (en) * 1984-05-15 1985-11-22 Radiotechnique FREQUENCY DEMODULATOR WITH ADJUSTABLE BANDWIDTH
JPH0253305A (en) * 1988-08-18 1990-02-22 Nippon Hoso Kyokai <Nhk> Fm demodulator
EP0709955A3 (en) * 1994-10-31 1996-10-09 Sharp Kk FM demodulator for reception of satellite broadcasting

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2564663A1 (en) * 1984-05-15 1985-11-22 Radiotechnique FREQUENCY DEMODULATOR WITH ADJUSTABLE BANDWIDTH
JPH0253305A (en) * 1988-08-18 1990-02-22 Nippon Hoso Kyokai <Nhk> Fm demodulator
EP0709955A3 (en) * 1994-10-31 1996-10-09 Sharp Kk FM demodulator for reception of satellite broadcasting

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