JPS57180209A - Fm signal demodulation system - Google Patents

Fm signal demodulation system

Info

Publication number
JPS57180209A
JPS57180209A JP6338481A JP6338481A JPS57180209A JP S57180209 A JPS57180209 A JP S57180209A JP 6338481 A JP6338481 A JP 6338481A JP 6338481 A JP6338481 A JP 6338481A JP S57180209 A JPS57180209 A JP S57180209A
Authority
JP
Japan
Prior art keywords
signal
band width
signal level
carrier
ratio
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
JP6338481A
Other languages
Japanese (ja)
Inventor
Tomozo Oota
Yoshihiro Konishi
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.)
Oki Electric Industry Co Ltd
Japan Broadcasting Corp
Original Assignee
Nippon Hoso Kyokai NHK
Oki Electric Industry Co Ltd
Japan Broadcasting 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 Nippon Hoso Kyokai NHK, Oki Electric Industry Co Ltd, Japan Broadcasting Corp filed Critical Nippon Hoso Kyokai NHK
Priority to JP6338481A priority Critical patent/JPS57180209A/en
Priority to CA000400870A priority patent/CA1190289A/en
Priority to AU82602/82A priority patent/AU551612B2/en
Priority to DE8282301963T priority patent/DE3268923D1/en
Priority to EP82301963A priority patent/EP0064819B1/en
Priority to US06/370,795 priority patent/US4563651A/en
Priority to MX192450A priority patent/MX151254A/en
Publication of JPS57180209A publication Critical patent/JPS57180209A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G5/00—Tone control or bandwidth control in amplifiers
    • H03G5/16—Automatic control
    • H03G5/24—Automatic control in frequency-selective amplifiers

Abstract

PURPOSE:To improve the SN ratio of a demodulation signal, by controlling the band width continuously or in step for a variable band pass filter changing the passing band width of the signal. CONSTITUTION:A part of a carrier Ci of an input signal from an input terminal 6 is detected at a signal level detector 1 and an output corresponding to the amplitude of the signal level is obtained. Other parts of the carrier Ci enters a variable band pass filter 2 through an amplifier 5. In this filter 2, as the signal level is smaller around the threshold value through the output of the signal level detector 1, the pass band width is narrower continuously or stepwise. Thus, the noise band width of a signal entering to a discriminator 3 is decided. Then, the carrier power versus noise power ratio C/N of the input signal giving to the discriminator 3 is improved and the SN ratio of the demodulation signal is improved.
JP6338481A 1981-04-28 1981-04-28 Fm signal demodulation system Pending JPS57180209A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
JP6338481A JPS57180209A (en) 1981-04-28 1981-04-28 Fm signal demodulation system
CA000400870A CA1190289A (en) 1981-04-28 1982-04-13 Fm signal demodulation system
AU82602/82A AU551612B2 (en) 1981-04-28 1982-04-14 Fm demodulator
DE8282301963T DE3268923D1 (en) 1981-04-28 1982-04-16 An fm signal demodulation system
EP82301963A EP0064819B1 (en) 1981-04-28 1982-04-16 An fm signal demodulation system
US06/370,795 US4563651A (en) 1981-04-28 1982-04-22 FM Demodulator with variable bandpass filter
MX192450A MX151254A (en) 1981-04-28 1982-04-27 IMPROVEMENTS IN THE DEMODULATION SYSTEM FOR A MODULATED TELEVISION SIGNAL

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6338481A JPS57180209A (en) 1981-04-28 1981-04-28 Fm signal demodulation system

Publications (1)

Publication Number Publication Date
JPS57180209A true JPS57180209A (en) 1982-11-06

Family

ID=13227741

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6338481A Pending JPS57180209A (en) 1981-04-28 1981-04-28 Fm signal demodulation system

Country Status (1)

Country Link
JP (1) JPS57180209A (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4973962A (en) * 1972-11-15 1974-07-17

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4973962A (en) * 1972-11-15 1974-07-17

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