GB2243274A - Subtracting ambient noise from total noise during recording or broadcasting - Google Patents

Subtracting ambient noise from total noise during recording or broadcasting Download PDF

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Publication number
GB2243274A
GB2243274A GB9003845A GB9003845A GB2243274A GB 2243274 A GB2243274 A GB 2243274A GB 9003845 A GB9003845 A GB 9003845A GB 9003845 A GB9003845 A GB 9003845A GB 2243274 A GB2243274 A GB 2243274A
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GB
United Kingdom
Prior art keywords
sound
ambient noise
signal
broadcasting
recording
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.)
Withdrawn
Application number
GB9003845A
Other versions
GB9003845D0 (en
Inventor
Andrew Llewellyn Pilkington
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.)
SWITCHTOLL Ltd
Original Assignee
SWITCHTOLL 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 SWITCHTOLL Ltd filed Critical SWITCHTOLL Ltd
Priority to GB9003845A priority Critical patent/GB2243274A/en
Publication of GB9003845D0 publication Critical patent/GB9003845D0/en
Publication of GB2243274A publication Critical patent/GB2243274A/en
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/24—Signal processing not specific to the method of recording or reproducing; Circuits therefor for reducing noise
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/12—Arrangements for observation, testing or troubleshooting
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H60/00—Arrangements for broadcast applications with a direct linking to broadcast information or broadcast space-time; Broadcast-related systems
    • H04H60/02—Arrangements for generating broadcast information; Arrangements for generating broadcast-related information with a direct linking to broadcast information or to broadcast space-time; Arrangements for simultaneous generation of broadcast information and broadcast-related information
    • H04H60/07—Arrangements for generating broadcast information; Arrangements for generating broadcast-related information with a direct linking to broadcast information or to broadcast space-time; Arrangements for simultaneous generation of broadcast information and broadcast-related information characterised by processes or methods for the generation

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Signal Processing Not Specific To The Method Of Recording And Reproducing (AREA)

Abstract

Ambient noise, eg from a street, railway station or airport, is recorded in erasable memory 12. It can then be subtracted (totally or attenuated) from the total sound in unit 12. <IMAGE>

Description

Improvements in Recorded and Broadcast Sound Quality This invention relates to a method of and apparatus for improving recorded and broadcast sound quality.
Digital audio techniques currently available, obtained by recordings made under ideal conditions and played back using DAT systems or compact disc players, are in general leading the public to expect improved sound quality in broadcast recordings and live broadcasts, as well as in recordings in video/tape decks and the like, where provision for proper sound control is as inadequate for the amateur user as it is for the professional reporters and engineers involved, for example, in news gathering.
It is well known that the playback of noisy or old films and recordings can be improved by use of the Dolby system and many available signal filtering techniques, which in general aim to cut out sound frequencies within one or more frequency bands peripheral to the frequency band of the required sound.
However, these known techniques are generally not of significant advantage when a particular sound is being recorded or broadcast against a generally noisy background having a wide frequency range encompassing the frequency band of the required sound.
According to one aspect of the present invention, there is provided a method of sound broadcasting and/or sound recording wherein a sample of the ambient noise in a particular environment is stored and, during the broadcasting or recording of the total sound which includes a required subject sound in the same environment, the stored ambient noise sample is subtracted from the total sound signal to provide the sound signal which is broadcast or recorded.
According to another aspect of the invention, there is provided apparatus for sound broadcasting and/or sound recording comprising a high speed erasible memory for storing a signal representative of the ambient noise in a particular environment, and a signal subtraction circuit for receiving the output of the memory and a total sound signal which includes a required sound signal obtained from the same environment.
An adjustable signal attenuator may be provided sc that only a proportion of the magnitude of the ambient noise signal is stored or is subtracted from the total sound signal, whilst a sound level detector circuit may be operative to cut-out or attenuate the ambient noise signal during subtraction from the total sound signal, in the event that the ambient noise in the environment is variable or not continuous. It is also possible to incorporate a frequency filtering means in the input line to the memory in order to achieve frequency selective storage of the ambient sound.
In the case of an audio/video deck, for example, a first switching means will be provided to enable the user first to store the ambient sound, and a second switching means will enable the subtraction circuit to be made operative during recording of the total sound which includes the subject sound.
Application of the invention is envisaged, in particular, when a broadcast or recording of a particular subject sound, for example a persons speech, in a generally ncisy environment such as a crowded scene, a busy street, a railway station or airport or the like, is to be made.
The invention is exemplified in simplified block diagram form in the accompanying single figure of drawings.
Referring to the drawing, reference 10 denotes a high speed erasible memory and reference 12 denotes a signal subtraction circuit.
Initially, a signal representative of the ambient noise in a particular environment is fed into the memory 1 under the control of switch 14.
The total sound including a subject sound is subsequently fed to the subtraction circuit 12, which also receives the output of the memory 10 under the control of switch 16.
An adjustable attenuator 18 may be incorporated in series with switch 16, as well as a signal level discriminator 20.
In addition, although not shown, a frequency selective filter may be included in the signal input line to the memory 10.
The output on line 22 from the subtraction circuit is a substantially clear sound, with ambient noise substantially totally suppressed or attenuated to a chosen extent.

Claims (11)

Claims
1. A method of sound broadcasting and/or sound recording wherein a sample of the ambient noise in a particular environment is stored and, during the broadcasting or recording of the total sound which includes a required subject sound in the same environment, the stored ambient noise sample is subtracted from the total sound signal to provide the sound signal which is broadcast or recorded.
2. A method as claimed in claim 1, according to which only a proportion of the magnitude of the ambient noise signal is stored or subtracted.
3. A method as claimed in claim l or claim 2, according to which the ambient noise signal is automatically adjusted in level during subtraction.
4. A method as claimed in claim 1 or claim 2 or claim 3, according to which the storage of ambient noise is frequency selective.
5. Apparatus for sound broadcasting and/or sound recording comprising a high speed erasible memory for storing a signal representative of the ambient noise in a particular environment, and a signal subtraction circuit for receiving the output of the memory and a total sound signal which includes a required sound signal obtained from the same environment.
6. Apparatus according to claim 5, including an adjustable signal attenuator whereby only a required proportion of the ambient noise signal is stored or subtracted.
7. Apparatus as claimed in claim 5 or claim 6, including a sound level detector circuit for cutting out or attenuating the ambient noise signal in the event that the ambient noise in the environment is variable or noncontinuous.
8. Apparatus as claimed in any of claims 5 to 7, including a frequency selective filter in the input line to the memory.
9. Apparatus as claimed in any of claims 5 to 8, including a first switching means enabling a user to store the ambient sound, and a second switching means enabling the subtraction circuit to be made operative during the recording or broadcasting of the total sound.
10. A method of sound enhancement during broadcasting r recording substantially as hereinbefore described.
11. Apparatus for enhancement of recorded or broadcast sound substantially as hereinbefore described with reference to the accompanying drawing.
GB9003845A 1990-02-20 1990-02-20 Subtracting ambient noise from total noise during recording or broadcasting Withdrawn GB2243274A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9003845A GB2243274A (en) 1990-02-20 1990-02-20 Subtracting ambient noise from total noise during recording or broadcasting

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9003845A GB2243274A (en) 1990-02-20 1990-02-20 Subtracting ambient noise from total noise during recording or broadcasting

Publications (2)

Publication Number Publication Date
GB9003845D0 GB9003845D0 (en) 1990-04-18
GB2243274A true GB2243274A (en) 1991-10-23

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB9003845A Withdrawn GB2243274A (en) 1990-02-20 1990-02-20 Subtracting ambient noise from total noise during recording or broadcasting

Country Status (1)

Country Link
GB (1) GB2243274A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0629054A2 (en) * 1993-06-08 1994-12-14 Matsushita Electric Industrial Co., Ltd. Noise suppressing apparatus capable of preventing deterioration in high frequency signal characteristic after noise suppression and in balanced signal transmitting system
GB2285376A (en) * 1993-12-28 1995-07-05 Nec Corp Telephone noise cancelling circuit

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986000133A1 (en) * 1984-06-08 1986-01-03 Plessey Australia Pty. Limited Adaptive speech detector system
US4630304A (en) * 1985-07-01 1986-12-16 Motorola, Inc. Automatic background noise estimator for a noise suppression system
GB2176377A (en) * 1985-04-02 1986-12-17 Mobira Oy Voice operated switch
WO1987000366A1 (en) * 1985-07-01 1987-01-15 Motorola, Inc. Noise supression system
US4769847A (en) * 1985-10-30 1988-09-06 Nec Corporation Noise canceling apparatus
JPH01149695A (en) * 1987-12-07 1989-06-12 Sumitomo Metal Ind Ltd Microphone device for voice recognition
GB2212035A (en) * 1987-11-01 1989-07-12 Ricoh Kk Noise suppression apparatus

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986000133A1 (en) * 1984-06-08 1986-01-03 Plessey Australia Pty. Limited Adaptive speech detector system
GB2176377A (en) * 1985-04-02 1986-12-17 Mobira Oy Voice operated switch
US4630304A (en) * 1985-07-01 1986-12-16 Motorola, Inc. Automatic background noise estimator for a noise suppression system
WO1987000366A1 (en) * 1985-07-01 1987-01-15 Motorola, Inc. Noise supression system
US4769847A (en) * 1985-10-30 1988-09-06 Nec Corporation Noise canceling apparatus
GB2212035A (en) * 1987-11-01 1989-07-12 Ricoh Kk Noise suppression apparatus
JPH01149695A (en) * 1987-12-07 1989-06-12 Sumitomo Metal Ind Ltd Microphone device for voice recognition

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0629054A2 (en) * 1993-06-08 1994-12-14 Matsushita Electric Industrial Co., Ltd. Noise suppressing apparatus capable of preventing deterioration in high frequency signal characteristic after noise suppression and in balanced signal transmitting system
EP0629054A3 (en) * 1993-06-08 1997-01-29 Matsushita Electric Ind Co Ltd Noise suppressing apparatus capable of preventing deterioration in high frequency signal characteristic after noise suppression and in balanced signal transmitting system.
US5982901A (en) * 1993-06-08 1999-11-09 Matsushita Electric Industrial Co., Ltd. Noise suppressing apparatus capable of preventing deterioration in high frequency signal characteristic after noise suppression and in balanced signal transmitting system
GB2285376A (en) * 1993-12-28 1995-07-05 Nec Corp Telephone noise cancelling circuit
US5617472A (en) * 1993-12-28 1997-04-01 Nec Corporation Noise suppression of acoustic signal in telephone set
GB2285376B (en) * 1993-12-28 1998-08-19 Nec Corp Noise suppression of acoustic signal in telephone set

Also Published As

Publication number Publication date
GB9003845D0 (en) 1990-04-18

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)