GB741333A - Improvements relating to electro-acoustic apparatus - Google Patents

Improvements relating to electro-acoustic apparatus

Info

Publication number
GB741333A
GB741333A GB1494453A GB1494453A GB741333A GB 741333 A GB741333 A GB 741333A GB 1494453 A GB1494453 A GB 1494453A GB 1494453 A GB1494453 A GB 1494453A GB 741333 A GB741333 A GB 741333A
Authority
GB
United Kingdom
Prior art keywords
pulse
signal
generator
noise
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.)
Expired
Application number
GB1494453A
Inventor
David Theodore Nels Williamson
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.)
Ferranti International PLC
Original Assignee
Ferranti PLC
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 Ferranti PLC filed Critical Ferranti PLC
Priority to GB1494453A priority Critical patent/GB741333A/en
Publication of GB741333A publication Critical patent/GB741333A/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
    • H03G3/34—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

741,333. Sound reproducing circuits. FERRANTI, Ltd. May 27, 1954 [May 29, 1953], No. 14944/53. Class 40 (4). A circuit for eliminating noise having a pulsed waveform from the output of a gramophone pick-up 10, comprises a gate 15 adapted to be closed by the output from a pulse generator 19 triggered by the rectified output of a filter 17 which passes only the ultra-audio frequencies which would be present in a noise of this type. The main signal path may include a delay line 14 so that the noise pulse may occur at the midpoint of the blocking pulse. The trailing edge of the blocking pulse from the generator 20 may trigger a further pulse generator 20 whose output prevents the further operation of the generator 19 for a prescribed period thereby preventing too-frequent blocking of the signal. A bypath 34 to the delay line 14 may be provided, the gate 15 being arranged to feed the undelayed signal to the reproducer 13 during the interval when the delayed signal is blocked, thereby maintaining continuity of signal. The gating circuit may comprise two gates operated in push-pull to avoid unwanted noise due to the application of the gating voltages.
GB1494453A 1953-05-29 1953-05-29 Improvements relating to electro-acoustic apparatus Expired GB741333A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1494453A GB741333A (en) 1953-05-29 1953-05-29 Improvements relating to electro-acoustic apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1494453A GB741333A (en) 1953-05-29 1953-05-29 Improvements relating to electro-acoustic apparatus

Publications (1)

Publication Number Publication Date
GB741333A true GB741333A (en) 1955-11-30

Family

ID=10050285

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1494453A Expired GB741333A (en) 1953-05-29 1953-05-29 Improvements relating to electro-acoustic apparatus

Country Status (1)

Country Link
GB (1) GB741333A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4076969A (en) * 1975-04-07 1978-02-28 Singer & Singer Impulse noise reduction system
US4119812A (en) * 1977-04-20 1978-10-10 Rca Corporation Signal defect detection and compensation with signal de-emphasis
US4184178A (en) * 1972-11-30 1980-01-15 Basf Aktiengesellschaft Drop-out compensator for sound reproducing apparatus during tape reversal
US5394274A (en) * 1988-01-22 1995-02-28 Kahn; Leonard R. Anti-copy system utilizing audible and inaudible protection signals

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4184178A (en) * 1972-11-30 1980-01-15 Basf Aktiengesellschaft Drop-out compensator for sound reproducing apparatus during tape reversal
US4076969A (en) * 1975-04-07 1978-02-28 Singer & Singer Impulse noise reduction system
US4119812A (en) * 1977-04-20 1978-10-10 Rca Corporation Signal defect detection and compensation with signal de-emphasis
US5394274A (en) * 1988-01-22 1995-02-28 Kahn; Leonard R. Anti-copy system utilizing audible and inaudible protection signals

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