JPS5735426A - Noise detecting circuit - Google Patents

Noise detecting circuit

Info

Publication number
JPS5735426A
JPS5735426A JP7726781A JP7726781A JPS5735426A JP S5735426 A JPS5735426 A JP S5735426A JP 7726781 A JP7726781 A JP 7726781A JP 7726781 A JP7726781 A JP 7726781A JP S5735426 A JPS5735426 A JP S5735426A
Authority
JP
Japan
Prior art keywords
circuit
noise
amplifier
agc
output
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
JP7726781A
Other languages
Japanese (ja)
Inventor
Kiyoshi Amasawa
Seiji Mori
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.)
Faurecia Clarion Electronics Co Ltd
Original Assignee
Clarion 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 Clarion Co Ltd filed Critical Clarion Co Ltd
Priority to JP7726781A priority Critical patent/JPS5735426A/en
Publication of JPS5735426A publication Critical patent/JPS5735426A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/34—Muting amplifier when no signal is present or when only weak signals are present, or caused by the presence of noise signals, e.g. squelch systems
    • H03G3/345—Muting during a short period of time when noise pulses are detected, i.e. blanking

Landscapes

  • Noise Elimination (AREA)

Abstract

PURPOSE:To detect a small pulsive noise, by providing an AGC loop without AGC at the detection of noise in a noise amplifier. CONSTITUTION:The output of a mixing stage 2 is detected at a detecting circuit 4 via a broad band amplifier 3. The output of the amplifier 3 is held at almost constant value with an AGC circuit 5. A pulsive noise is picked up in the output of the circuit 4 from an amplfier 7 via an HPF 6. This pulsive noise produces a gate pulse at a Schmitt circuit 8. If a strong signal is present and gate pulses are consecutive, an AGC circuit 9 controls the gain of the amplifier 7 to avoid the circuit 8 from being continuously operated. If noise is present continuously, the output of the amplifier 7 is smaller and an electronic switch 10 which stops the AGC circuit 9 is provided to prevent the Schmitt circuit from being inoperative.
JP7726781A 1981-05-21 1981-05-21 Noise detecting circuit Pending JPS5735426A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP7726781A JPS5735426A (en) 1981-05-21 1981-05-21 Noise detecting circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7726781A JPS5735426A (en) 1981-05-21 1981-05-21 Noise detecting circuit

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
JP13387876A Division JPS5358712A (en) 1976-11-08 1976-11-08 Noise detecting circuit

Publications (1)

Publication Number Publication Date
JPS5735426A true JPS5735426A (en) 1982-02-26

Family

ID=13629062

Family Applications (1)

Application Number Title Priority Date Filing Date
JP7726781A Pending JPS5735426A (en) 1981-05-21 1981-05-21 Noise detecting circuit

Country Status (1)

Country Link
JP (1) JPS5735426A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63122221U (en) * 1987-01-31 1988-08-09
JPH01225229A (en) * 1988-03-03 1989-09-08 Pioneer Electron Corp Pulse-like noise removing device in fm receiver
US6795559B1 (en) 1999-12-22 2004-09-21 Mitsubishi Denki Kabushiki Kaisha Impulse noise reducer detecting impulse noise from an audio signal

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63122221U (en) * 1987-01-31 1988-08-09
JPH01225229A (en) * 1988-03-03 1989-09-08 Pioneer Electron Corp Pulse-like noise removing device in fm receiver
US6795559B1 (en) 1999-12-22 2004-09-21 Mitsubishi Denki Kabushiki Kaisha Impulse noise reducer detecting impulse noise from an audio signal

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