JPS55140311A - Sound volume automatic control unit of noise control type speaker - Google Patents

Sound volume automatic control unit of noise control type speaker

Info

Publication number
JPS55140311A
JPS55140311A JP4927079A JP4927079A JPS55140311A JP S55140311 A JPS55140311 A JP S55140311A JP 4927079 A JP4927079 A JP 4927079A JP 4927079 A JP4927079 A JP 4927079A JP S55140311 A JPS55140311 A JP S55140311A
Authority
JP
Japan
Prior art keywords
noise
sound
section
amplifier
circuit
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
JP4927079A
Other languages
Japanese (ja)
Inventor
Shunsui Hirano
Takeshi Isogai
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.)
Toa Corp
Toa Tokushu Denki KK
Original Assignee
Toa Electric Co Ltd
Toa Tokushu Denki KK
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 Toa Electric Co Ltd, Toa Tokushu Denki KK filed Critical Toa Electric Co Ltd
Priority to JP4927079A priority Critical patent/JPS55140311A/en
Publication of JPS55140311A publication Critical patent/JPS55140311A/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 without distortion of the input signal
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/32—Automatic control in amplifiers having semiconductor devices the control being dependent upon ambient noise level or sound level

Abstract

PURPOSE:To simplify a circuit by detecting noise in a broadcasting soundless section and using this noise level as a control source until the next soundless section. CONSTITUTION:The output of differential microphone 1 for broadcasting is supplied to speaker 4 through amplifier 2 and gain control amplifier 3. The sound section where a sound signal exists and the soundless section where no sound signal exists are detected by sound discriminating circuit 5, and the detection signal is supplied to switch 7. Next, speaker 4 has the input cut off by the detection signal for the soundless section and operates as a microphone to detect ambient noise. This detection output is supplied to control voltage setting circuit 12 through amplifier 11, and the output is given to gain control amplifier 3 and becomes the control source of the broadcast sound volume until the next soundless section. Thus, the circuit can be simplified because a microphone for noise detection and so on are needless.
JP4927079A 1979-04-19 1979-04-19 Sound volume automatic control unit of noise control type speaker Pending JPS55140311A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP4927079A JPS55140311A (en) 1979-04-19 1979-04-19 Sound volume automatic control unit of noise control type speaker

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP4927079A JPS55140311A (en) 1979-04-19 1979-04-19 Sound volume automatic control unit of noise control type speaker

Publications (1)

Publication Number Publication Date
JPS55140311A true JPS55140311A (en) 1980-11-01

Family

ID=12826139

Family Applications (1)

Application Number Title Priority Date Filing Date
JP4927079A Pending JPS55140311A (en) 1979-04-19 1979-04-19 Sound volume automatic control unit of noise control type speaker

Country Status (1)

Country Link
JP (1) JPS55140311A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6079824U (en) * 1983-11-07 1985-06-03 富士通テン株式会社 Automatic volume control circuit for radio equipment
JPS6146605A (en) * 1984-08-11 1986-03-06 Matsushita Electric Ind Co Ltd Automatic sound volume adjusting device
JP2015149551A (en) * 2014-02-05 2015-08-20 東日本旅客鉄道株式会社 Volume controller

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4984314A (en) * 1972-12-18 1974-08-13

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4984314A (en) * 1972-12-18 1974-08-13

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6079824U (en) * 1983-11-07 1985-06-03 富士通テン株式会社 Automatic volume control circuit for radio equipment
JPS6146605A (en) * 1984-08-11 1986-03-06 Matsushita Electric Ind Co Ltd Automatic sound volume adjusting device
JPH0326926B2 (en) * 1984-08-11 1991-04-12 Matsushita Electric Ind Co Ltd
JP2015149551A (en) * 2014-02-05 2015-08-20 東日本旅客鉄道株式会社 Volume controller

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