GB1458663A - Microphone circuits - Google Patents
Microphone circuitsInfo
- Publication number
- GB1458663A GB1458663A GB107173*[A GB107173A GB1458663A GB 1458663 A GB1458663 A GB 1458663A GB 107173 A GB107173 A GB 107173A GB 1458663 A GB1458663 A GB 1458663A
- Authority
- GB
- United Kingdom
- Prior art keywords
- signal
- outputs
- unwanted
- microphones
- phase
- 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
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
- H04R3/02—Circuits for transducers, loudspeakers or microphones for preventing acoustic reaction, i.e. acoustic oscillatory feedback
Landscapes
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Otolaryngology (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
- Interconnected Communication Systems, Intercoms, And Interphones (AREA)
Abstract
1458663 Microphone circuits ARD ANSTALT 14 Dec 1973 [15 Dec 1972 9 Jan 1973] 58174/72 and 1071/73 Heading H4J Unwanted sound entering two microphones is substantially cancelled by processing the electrical outputs of the two microphones, each of which outputs contains a wanted component and an unwanted component. (Unwanted components correspond to those components of sound from a single source which differ in phase at the two microphones. Wanted components correspond to those components from a single source which have equal phase at the two microphones). From the outputs two signals are derived, a first signal representative of the wanted and unwanted components and a second signal representative of only the unwanted component. The phase and/or amplitude of the second signal relative to the unwanted component of a selected one of either of said outputs or of the first signal are/is adjusted so as to derive a third signal of equal amplitude and opposite phase to the unwanted signal. The third signal is then combined with the selected signal so as to derive a fourth signal representative substantially of only the wanted component. An application is loudspeaking telephone apparatus. The outputs of two microphones M (Fig. 1) are applied to an additive circuit A (e.g. a transformer or amplifier) and to a subtractive circuit S<SP>1</SP> (e.g. a transformer or differential amplifier). The additive and subtractive outputs are passed through respective phase and amplitude adjusters P and summed in an amplifier O. Its output is connected to an amplifier K and loudspeaker L through a hybrid H, if required, and through a line terminal T to like apparatus at a remote station. Outputs from the additive and subtractive circuits A and S<SP>1</SP> are also passed to an automatic gain control circuit G effective to control amplifiers O and K so as to eliminate any spurious changes arising from the signals being processed.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB107173*[A GB1458663A (en) | 1972-12-15 | 1973-01-09 | Microphone circuits |
US425527A US3922488A (en) | 1972-12-15 | 1973-12-17 | Feedback-cancelling electro-acoustic transducer apparatus |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB5817472 | 1972-12-15 | ||
GB107173*[A GB1458663A (en) | 1972-12-15 | 1973-01-09 | Microphone circuits |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1458663A true GB1458663A (en) | 1976-12-15 |
Family
ID=26236423
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB107173*[A Expired GB1458663A (en) | 1972-12-15 | 1973-01-09 | Microphone circuits |
Country Status (2)
Country | Link |
---|---|
US (1) | US3922488A (en) |
GB (1) | GB1458663A (en) |
Families Citing this family (28)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4025724A (en) * | 1975-08-12 | 1977-05-24 | Westinghouse Electric Corporation | Noise cancellation apparatus |
JPS5518186A (en) * | 1978-07-27 | 1980-02-08 | Sony Corp | Howling preventing inductive receiver |
US4306115A (en) * | 1980-03-19 | 1981-12-15 | Humphrey Francis S | Automatic volume control system |
US4473906A (en) * | 1980-12-05 | 1984-09-25 | Lord Corporation | Active acoustic attenuator |
FR2509938B1 (en) * | 1981-04-01 | 1987-11-13 | Trt Telecom Radio Electr | ARRANGEMENT OF ACOUSTIC TRANSDUCERS AND USE OF THIS ARRANGEMENT IN A "HANDS-FREE" TELEPHONE SET |
US4388711A (en) * | 1981-07-28 | 1983-06-14 | The United States Of America As Represented By The Secretary Of The Navy | Optimum flow noise cancelling hydrophone module |
US4644581A (en) * | 1985-06-27 | 1987-02-17 | Bose Corporation | Headphone with sound pressure sensing means |
US4837829A (en) * | 1986-01-15 | 1989-06-06 | Jaffe Acoustics, Inc. | Acoustic sound system for a room |
US4819263A (en) * | 1986-06-30 | 1989-04-04 | Cellular Communications Corporation | Apparatus and method for hands free telephonic communication |
US4823391A (en) * | 1986-07-22 | 1989-04-18 | Schwartz David M | Sound reproduction system |
NL8802516A (en) * | 1988-10-13 | 1990-05-01 | Philips Nv | HEARING AID WITH CIRCULAR SUPPRESSION. |
US5020101A (en) * | 1989-04-10 | 1991-05-28 | Gregory R. Brotz | Musicians telephone interface |
US5001763A (en) * | 1989-08-10 | 1991-03-19 | Mnc Inc. | Electroacoustic device for hearing needs including noise cancellation |
US5185803A (en) * | 1991-12-23 | 1993-02-09 | Ford Motor Company | Communication system for passenger vehicle |
US5812659A (en) * | 1992-05-11 | 1998-09-22 | Jabra Corporation | Ear microphone with enhanced sensitivity |
ATE211339T1 (en) * | 1992-05-11 | 2002-01-15 | Jabra Corp | UNIDIRECTIONAL EAR MICROPHONE AND METHOD THEREOF |
US5373555A (en) * | 1992-05-11 | 1994-12-13 | Jabra Corporation | Unidirectional ear microphone and gasket |
FR2702118B1 (en) * | 1993-02-23 | 1995-05-05 | Gregoire Le Tourneur | Multisensor device for sound pickup and associated signal processing. |
US6594688B2 (en) | 1993-10-01 | 2003-07-15 | Collaboration Properties, Inc. | Dedicated echo canceler for a workstation |
US5771278A (en) * | 1993-12-27 | 1998-06-23 | Cirrus Logic, Inc. | Method and apparatus for minimizing system oscillations caused by acoustical coupling |
US5524058A (en) * | 1994-01-12 | 1996-06-04 | Mnc, Inc. | Apparatus for performing noise cancellation in telephonic devices and headwear |
WO1997007624A1 (en) * | 1995-08-21 | 1997-02-27 | Telefonaktiebolaget Lm Ericsson (Publ) | Echo cancelling using signal preprocessing in an acoustic environment |
AUPO714197A0 (en) | 1997-06-02 | 1997-06-26 | University Of Melbourne, The | Multi-strategy array processor |
FI114422B (en) | 1997-09-04 | 2004-10-15 | Nokia Corp | Source speech activity detection |
GB9800796D0 (en) * | 1998-01-16 | 1998-03-11 | Mumford Ray | Feedback control circuit |
US6415029B1 (en) * | 1999-05-24 | 2002-07-02 | Motorola, Inc. | Echo canceler and double-talk detector for use in a communications unit |
US7069061B2 (en) * | 2003-07-18 | 2006-06-27 | Sony Ericsson Mobile Communications Ab | Speaker assemblies and mobile terminals including the same |
US8652040B2 (en) | 2006-12-19 | 2014-02-18 | Valencell, Inc. | Telemetric apparatus for health and environmental monitoring |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR856727A (en) * | 1938-06-24 | 1940-08-03 | Telefunken Gmbh | System to avoid acoustic reactions in speech broadcasting installations |
US2177769A (en) * | 1938-12-24 | 1939-10-31 | Frank I Du Frane Company Inc | Loud-speaking intercommunicating system |
US2208160A (en) * | 1939-10-19 | 1940-07-16 | Harold J Mccreary | Communication system |
US3105877A (en) * | 1960-09-12 | 1963-10-01 | Itt | Circuit for canceling oscillating in public address systems |
US3588352A (en) * | 1966-03-28 | 1971-06-28 | Ichiro Yamawaki | Howling elimination system for use in simultaneous two-way communicating device and a howlingless simultaneous two-way communicating device |
US3588360A (en) * | 1969-02-03 | 1971-06-28 | Post Office | Telecommunication systems |
US3784747A (en) * | 1971-12-03 | 1974-01-08 | Bell Telephone Labor Inc | Speech suppression by predictive filtering |
-
1973
- 1973-01-09 GB GB107173*[A patent/GB1458663A/en not_active Expired
- 1973-12-17 US US425527A patent/US3922488A/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
US3922488A (en) | 1975-11-25 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed [section 19, patents act 1949] | ||
PCNP | Patent ceased through non-payment of renewal fee |