GB1518574A - Sound reproducing system - Google Patents

Sound reproducing system

Info

Publication number
GB1518574A
GB1518574A GB2281676A GB2281676A GB1518574A GB 1518574 A GB1518574 A GB 1518574A GB 2281676 A GB2281676 A GB 2281676A GB 2281676 A GB2281676 A GB 2281676A GB 1518574 A GB1518574 A GB 1518574A
Authority
GB
United Kingdom
Prior art keywords
signal
noise level
noise
gain
amplifier
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
GB2281676A
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Priority to GB2281676A priority Critical patent/GB1518574A/en
Publication of GB1518574A publication Critical patent/GB1518574A/en
Expired 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
    • H03G3/32—Automatic control in amplifiers having semiconductor devices the control being dependent upon ambient noise level or sound level
    • 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

Landscapes

  • Control Of Amplification And Gain Control (AREA)

Abstract

1518574 Gain control systems J. FRICKE and U. R. MœLLER 2 June 1976 22816/76 Heading H4R In a sound reproduction system for reproducing sound in a noisy environment the output level of the signal is increased and the dynamic range reduced when the noise level increases. As described when the ambient noise level, as picked up by a microphone 31, is low sound signals from a radio receiver 10 are fed via variable gain amplifier 27 to a power amplifier 14 for reproduction by a loudspeaker 18. As the noise level increases the gain of amplifier 27 is increased by about 4dB for each 10dB increase in noise level. At a predetermined noise level, threshold circuit 35 operates to insert a compressor amplifier 23 into the signal path, and at a second noise level a second threshold circuit inserts a second compressor amplifier 25. Other threshold circuits 43, 45, are responsive to particular frequency components in the noise to insert respective filters 51 and 53 in the signal path to increase the signal gain at frequencies predominant in the noise. The control voltage can be derived via a sample and hold circuit 31a which samples the noise when the signal being reproduced is at low level. In an alternative arrangement Fig. 3 (not shown) the frequency spectrum of the signal and the noise is broken up into a number of contiguous bands and the signal gain and compression in each band controlled in dependence on the noise level in the same band. In this system the signal is interrupted at regular intervals and the noise level sampled during the interruptions and a control voltage developed and held until the following interruption.
GB2281676A 1976-06-02 1976-06-02 Sound reproducing system Expired GB1518574A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2281676A GB1518574A (en) 1976-06-02 1976-06-02 Sound reproducing system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2281676A GB1518574A (en) 1976-06-02 1976-06-02 Sound reproducing system

Publications (1)

Publication Number Publication Date
GB1518574A true GB1518574A (en) 1978-07-19

Family

ID=10185505

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2281676A Expired GB1518574A (en) 1976-06-02 1976-06-02 Sound reproducing system

Country Status (1)

Country Link
GB (1) GB1518574A (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2449364A1 (en) * 1979-02-16 1980-09-12 Eller Fritz METHOD AND ARRANGEMENT FOR CONTROLLING A SOURCE OF ITS USEFUL
DE3224078A1 (en) * 1981-06-29 1983-01-27 Hitachi, Ltd., Tokyo AUTOMATIC VOLUME CONTROL FOR SOUND PLAYBACK DEVICES IN MOTOR VEHICLES
GB2207313A (en) * 1987-07-18 1989-01-25 James Melville Buick Signal controlled by noise signal compensator
GB2214013A (en) * 1988-01-14 1989-08-23 Hazel Grove Music Co Ltd Sound level control equipment
GB2237463A (en) * 1989-10-16 1991-05-01 John Moffatt Automatic volume control system responding to ambient noise
GB2238680A (en) * 1989-12-01 1991-06-05 Hazel Grove Music Co Ltd Sound level control equipment
GB2249888A (en) * 1990-10-03 1992-05-20 Hazel Grove Music Co Ltd Sound level control equipment
GB2257317A (en) * 1991-06-26 1993-01-06 Damian Rupert Lindley Automatic volume control for car stereo
EP0578008A1 (en) * 1992-07-04 1994-01-12 Blaupunkt-Werke GmbH Vehicular radio receiver with speed compensated tone control
WO2003019775A2 (en) * 2001-08-23 2003-03-06 Koninklijke Philips Electronics N.V. Audio processing device

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2449364A1 (en) * 1979-02-16 1980-09-12 Eller Fritz METHOD AND ARRANGEMENT FOR CONTROLLING A SOURCE OF ITS USEFUL
DE3224078A1 (en) * 1981-06-29 1983-01-27 Hitachi, Ltd., Tokyo AUTOMATIC VOLUME CONTROL FOR SOUND PLAYBACK DEVICES IN MOTOR VEHICLES
GB2207313A (en) * 1987-07-18 1989-01-25 James Melville Buick Signal controlled by noise signal compensator
GB2214013B (en) * 1988-01-14 1992-04-22 Hazel Grove Music Co Ltd Sound level control equipment
GB2214013A (en) * 1988-01-14 1989-08-23 Hazel Grove Music Co Ltd Sound level control equipment
GB2237463A (en) * 1989-10-16 1991-05-01 John Moffatt Automatic volume control system responding to ambient noise
GB2237463B (en) * 1989-10-16 1994-01-05 John Moffatt Automatic volume control system
GB2238680A (en) * 1989-12-01 1991-06-05 Hazel Grove Music Co Ltd Sound level control equipment
GB2238680B (en) * 1989-12-01 1994-01-26 Hazel Grove Music Co Ltd Sound level control equipment
GB2249888A (en) * 1990-10-03 1992-05-20 Hazel Grove Music Co Ltd Sound level control equipment
GB2257317A (en) * 1991-06-26 1993-01-06 Damian Rupert Lindley Automatic volume control for car stereo
EP0578008A1 (en) * 1992-07-04 1994-01-12 Blaupunkt-Werke GmbH Vehicular radio receiver with speed compensated tone control
WO2003019775A2 (en) * 2001-08-23 2003-03-06 Koninklijke Philips Electronics N.V. Audio processing device
WO2003019775A3 (en) * 2001-08-23 2004-02-05 Koninkl Philips Electronics Nv Audio processing device
US7203325B2 (en) 2001-08-23 2007-04-10 Koninklijke Philips Electronics N.V. Audio processing device

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee