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GB1228795A - - Google Patents

Info

Publication number
GB1228795A
GB1228795A GB1228795DA GB1228795A GB 1228795 A GB1228795 A GB 1228795A GB 1228795D A GB1228795D A GB 1228795DA GB 1228795 A GB1228795 A GB 1228795A
Authority
GB
United Kingdom
Prior art keywords
khz
control amplifier
fed
pass filter
signal path
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.)
Expired
Application number
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 filed Critical
Publication of GB1228795A publication Critical patent/GB1228795A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G9/00—Combinations of two or more types of control, e.g. gain control and tone control
    • H03G9/02—Combinations of two or more types of control, e.g. gain control and tone control in untuned amplifiers
    • H03G9/025—Combinations of two or more types of control, e.g. gain control and tone control in untuned amplifiers frequency-dependent volume compression or expansion, e.g. multiple-band systems

Landscapes

  • Signal Processing Not Specific To The Method Of Recording And Reproducing (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)

Abstract

1,228,795. Automatic volume control. LES INDUSTRIES MUSICALES ET ELECTRIQUES PATHE MARCONI. 29 May, 1968 [31 May, 1967], No. 25668/68. Heading H4R. A voice recording system includes a variable attenuator in the signal path controlled by a sibilant detector to reduce the recorded level when sibilants are detected. As shown in Fig. 3 the detector includes a high pass filter 12, passing frequencies above 6 kHz, and a low pass filter, passing frequencies below 2 kHz, the outputs from which are fed to the diode mixing circuit 14, 15, 16, which passes signals to the control amplifier only when frequencies above 6 kHz are present alone. The control amplifier feeds a lamp 18 which illuminates a photosensitive resistor 19 to increase the attenuation in the signal path from terminals 22 to 23 when a signal is fed to the control amplifier 17.
GB1228795D 1967-05-31 1968-05-29 Expired GB1228795A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR108518 1967-05-31

Publications (1)

Publication Number Publication Date
GB1228795A true GB1228795A (en) 1971-04-21

Family

ID=8632001

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1228795D Expired GB1228795A (en) 1967-05-31 1968-05-29

Country Status (1)

Country Link
GB (1) GB1228795A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2747821A1 (en) * 1976-11-08 1978-05-11 Philips Nv AMPLIFIER ARRANGEMENT FOR ACOUSTIC SIGNALS WITH MEANS TO SUPPRESS UNWANTED INTERFERENCE SIGNALS
EP0235848A1 (en) * 1986-02-18 1987-09-09 Koninklijke Philips Electronics N.V. Automatically controlled amplifier arrangement
US5371803A (en) * 1990-08-31 1994-12-06 Bellsouth Corporation Tone reduction circuit for headsets
US5701352A (en) * 1994-07-14 1997-12-23 Bellsouth Corporation Tone suppression automatic gain control for a headset

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2747821A1 (en) * 1976-11-08 1978-05-11 Philips Nv AMPLIFIER ARRANGEMENT FOR ACOUSTIC SIGNALS WITH MEANS TO SUPPRESS UNWANTED INTERFERENCE SIGNALS
EP0235848A1 (en) * 1986-02-18 1987-09-09 Koninklijke Philips Electronics N.V. Automatically controlled amplifier arrangement
US5371803A (en) * 1990-08-31 1994-12-06 Bellsouth Corporation Tone reduction circuit for headsets
US5701352A (en) * 1994-07-14 1997-12-23 Bellsouth Corporation Tone suppression automatic gain control for a headset

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Legal Events

Date Code Title Description
PS Patent sealed
PLNP Patent lapsed through nonpayment of renewal fees