EP0034613A1 - Acoustic coupler cavity lineariser - Google Patents

Acoustic coupler cavity lineariser

Info

Publication number
EP0034613A1
EP0034613A1 EP19800901635 EP80901635A EP0034613A1 EP 0034613 A1 EP0034613 A1 EP 0034613A1 EP 19800901635 EP19800901635 EP 19800901635 EP 80901635 A EP80901635 A EP 80901635A EP 0034613 A1 EP0034613 A1 EP 0034613A1
Authority
EP
European Patent Office
Prior art keywords
acoustic coupler
cavity
acoustic
plug
coupler according
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Withdrawn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
EP19800901635
Other languages
German (de)
French (fr)
Inventor
David Scott Whitby
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.)
ELECTRO MEDICAL ENGINEERING PTY Ltd
Original Assignee
ELECTRO MEDICAL ENGINEERING PTY 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 ELECTRO MEDICAL ENGINEERING PTY Ltd filed Critical ELECTRO MEDICAL ENGINEERING PTY Ltd
Publication of EP0034613A1 publication Critical patent/EP0034613A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04MTELEPHONIC COMMUNICATION
    • H04M1/00Substation equipment, e.g. for use by subscribers
    • H04M1/02Constructional features of telephone sets
    • H04M1/21Combinations with auxiliary equipment, e.g. with clocks or memoranda pads
    • H04M1/215Combinations with auxiliary equipment, e.g. with clocks or memoranda pads by non-intrusive coupling means, e.g. acoustic couplers
    • H04M1/2155Acoustic coupling

Definitions

  • This invention relates to improvements in acoustic couplers for the transmission of computer or other data over telephone lines.
  • Acoustic couplers are used for the transmission and reception of encoded data signals by coupling the encoded signal in audio frequency sound form from a suitable transducer to the telephone handset microphone, and from the telephone handset receiver by a suitable microphone.
  • the coupling transducers are held in a suitable mechanical arrangement and surrounded by acoustic seals usually formed from rubber or a rubber like substance, and a telephone.handset is mechanically held in contact with the arrangement for transference of acoustic signals.
  • acoustic couplers used for frequenc modulated analog signals such as facsimile or medical telemetry signals perform quite well.
  • da transmission speeds are higher, for example, in the vic of 1200 BPS, and phase modulated and wide band FM signa are used, the limitations of conventional acoustic coup become more apparent. These limitations are caused in by uneven phase, frequency, and amplitude response of t coupler transducers and cavities, as well as acoustic t delays which become appreciable with higher speed and w bandwidth signals.
  • An object of the present invention is to substantially overcome the deficiencies of acoustic cou at high data transmission speeds.
  • a acoustic coupler for transmitting and/or receiving encoded data signals over telephone lines, said acousti coupler including data transmitting and/or receiving elements (20,28) to which a telephone handset (10) is acoustically coupled in audio frequency sound form, and which in use a cavity (32) exists between respective telephone handset transducers and data transmitting and receiving transducers, characterized in that a plug (36 of material is provided in said cavity.
  • Fig. 1 is a diagrammatic partly-sectioned view the essential features of an acoustic coupler, together with a separated telephone handset.
  • the telephone handset 10 is of conventional design, being connected by a cord 12 to a control termi
  • the handset includes a receiving end 14, which includes a microphone, and a transmitting end 16, which includes an acoustic transducer.
  • the duplex acoustic coupler structure 18 includes a transmitting element 20, which has an annular acoustic seal 22, preferably formed from a resilient material such as rubber, which seal is adapted to co-operate with telephone handset receiving end 14 to define, in use, an acoustic cavity 24.
  • a transmit transducer 26 is located within the seal to transmit, in audio frequency form, encoded data to the receiving microphone in receiving end 14.
  • the receive/transmit handset/coupler arrangement 14/20 is not shown with a plug of material in accordance with the invention, for clarity, and because the acoustic coupler problems described herein are not so apparent in this mode.
  • the features of the coupler structure which are not shown may include a flexible central portion to enable the relative angle of the coupler elements to be altered to accommodate various telephone handset types.
  • the coupler 18 also includes a receiving element 28, which has an acoustic seal 30 which is substantially identical, in construction and operation, to seal 20, and forms with end 16, in use, an acoustic cavity 32.
  • a receiver microphone 34 is located within seal 30.
  • a plug 36 is located within seal 30.
  • the plug is preferably formed from resilient semi-open pore material such as a foamed plastics material, although the structure and degree of compressibility may be altered to change operating parameters.
  • the plug is shown in a cylindrical form, with a curved top edge 38.
  • An axial aperture 40 extends through the plug.
  • the plug is preferably formed in a size greater than the expected cavity size, so that in use, when end 16 is located to abut seal 30, the end also deforms plug 36 to fill the entire cavity 32, although leaving aperture 40, in a truncated form.
  • the plug 36 acts as a damping device in the air cavity 32, and as a consequence reduces the resonances within the cavity.
  • the plug also modifies the time delay of sound travelling across the cavity, and reduces the difference in time delay between two or more given frequencies within the bandwidth used. Depending on the degree -of the compressibility of the plug material, the damping effect on the air cavity will vary.
  • the apertured embodiment shown is considered superior in that the aperture 40 provides direct transducer/ transducer communication, through the air, thus not decreasing, sensitivity, whilst maintaining the damping effect by filling the remainder of the cavity 32.
  • plugs of different sizes, shapes, and/ or materials may be fitted with double sided adhesive pads or discs so that they may be added to, removed from, or changed in acoustic coupler air cavities for the purpose of optimising the performance, or equalizing the response, so that the acoustic coupler could be used with, for instance, different types of telephone handsets, or adapt to different line conditions.

Landscapes

  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Telephone Set Structure (AREA)

Abstract

Un coupleur acoustique (18) de transmission et/ou de reception de signaux de donnees codees par des lignes telephoniques auxquelles, en fonctionnement, un ecouteur telephonique (10) est couple acoustiquement. Une cavite (32) est formee entre l'ecouteur (10) et un joint acoustique (30), entourant un transducteur (34). Un tampon (36) de materiau est place dans la cavite(32); en fonctionnement, ce tampon est deforme entre l'ecouteur (10) et le coupleur (18) pour remplir la cavite linearisant ainsi la transmission de donnees sous forme de sons d'audio frequence au travers de la cavite (32). Une ouverture (40) peut etre amenagee dans le tampon pour augmenter la sensibilite.An acoustic coupler (18) for transmitting and / or receiving data signals encoded by telephone lines to which, in operation, a telephone receiver (10) is acoustically coupled. A cavity (32) is formed between the earpiece (10) and an acoustic seal (30), surrounding a transducer (34). A pad (36) of material is placed in the cavity (32); in operation, this buffer is deformed between the earpiece (10) and the coupler (18) to fill the cavity thereby linearising the transmission of data in the form of audio frequency sounds through the cavity (32). An opening (40) can be made in the tampon to increase sensitivity.

Description

TITLE: ACOUSTIC COUPLER.CAVITY LINEARISER
This invention relates to improvements in acoustic couplers for the transmission of computer or other data over telephone lines.
Acoustic couplers are used for the transmission and reception of encoded data signals by coupling the encoded signal in audio frequency sound form from a suitable transducer to the telephone handset microphone, and from the telephone handset receiver by a suitable microphone. In a conventional acoustic coupler, the coupling transducers are held in a suitable mechanical arrangement and surrounded by acoustic seals usually formed from rubber or a rubber like substance, and a telephone.handset is mechanically held in contact with the arrangement for transference of acoustic signals.
There is normally an air cavity between the telephone handset transducers and the acoustic coupler transducers. Such cavities are usually present to improve the coupling efficiency and frequency response of the overall system, included in which are the telephone handset transducers. It is also necessary to have some air cavity, as the acoustic seal around the coupling transducers must be made of a resilient material having enough compliance to make an efficient acoustic seal with a wide range of telephone handset designs.
In data transmission using FSK transmission techniques, conventional acoustic couplers perform satisfactorily up to speeds in the vicinity of 300 to 6 bits per second (BPS) .
Similarly, acoustic couplers used for frequenc modulated analog signals such as facsimile or medical telemetry signals perform quite well. However, when da transmission speeds are higher, for example, in the vic of 1200 BPS, and phase modulated and wide band FM signa are used, the limitations of conventional acoustic coup become more apparent. These limitations are caused in by uneven phase, frequency, and amplitude response of t coupler transducers and cavities, as well as acoustic t delays which become appreciable with higher speed and w bandwidth signals. An object of the present invention is to substantially overcome the deficiencies of acoustic cou at high data transmission speeds.
According to the invention there is provided a acoustic coupler (18) for transmitting and/or receiving encoded data signals over telephone lines, said acousti coupler including data transmitting and/or receiving elements (20,28) to which a telephone handset (10) is acoustically coupled in audio frequency sound form, and which in use a cavity (32) exists between respective telephone handset transducers and data transmitting and receiving transducers, characterized in that a plug (36 of material is provided in said cavity.
An embodiment of the invention will be describ hereinafter, with reference to the accompanying drawing in which:-
Fig. 1 is a diagrammatic partly-sectioned view the essential features of an acoustic coupler, together with a separated telephone handset. The telephone handset 10 is of conventional design, being connected by a cord 12 to a control termi
-_O The handset includes a receiving end 14, which includes a microphone, and a transmitting end 16, which includes an acoustic transducer.
The duplex acoustic coupler structure 18 includes a transmitting element 20, which has an annular acoustic seal 22, preferably formed from a resilient material such as rubber, which seal is adapted to co-operate with telephone handset receiving end 14 to define, in use, an acoustic cavity 24. A transmit transducer 26 is located within the seal to transmit, in audio frequency form, encoded data to the receiving microphone in receiving end 14.
The receive/transmit handset/coupler arrangement 14/20 is not shown with a plug of material in accordance with the invention, for clarity, and because the acoustic coupler problems described herein are not so apparent in this mode.
The features of the coupler structure which are not shown may include a flexible central portion to enable the relative angle of the coupler elements to be altered to accommodate various telephone handset types.
The coupler 18 also includes a receiving element 28, which has an acoustic seal 30 which is substantially identical, in construction and operation, to seal 20, and forms with end 16, in use, an acoustic cavity 32. A receiver microphone 34 is located within seal 30. A plug 36 is located within seal 30. The plug is preferably formed from resilient semi-open pore material such as a foamed plastics material, although the structure and degree of compressibility may be altered to change operating parameters. The plug is shown in a cylindrical form, with a curved top edge 38. An axial aperture 40 extends through the plug.
The plug is preferably formed in a size greater than the expected cavity size, so that in use, when end 16 is located to abut seal 30, the end also deforms plug 36 to fill the entire cavity 32, although leaving aperture 40, in a truncated form.
The plug 36 acts as a damping device in the air cavity 32, and as a consequence reduces the resonances within the cavity. The plug also modifies the time delay of sound travelling across the cavity, and reduces the difference in time delay between two or more given frequencies within the bandwidth used. Depending on the degree -of the compressibility of the plug material, the damping effect on the air cavity will vary.
The apertured embodiment shown is considered superior in that the aperture 40 provides direct transducer/ transducer communication, through the air, thus not decreasing, sensitivity, whilst maintaining the damping effect by filling the remainder of the cavity 32.
It is clear that if plugs of different sizes and/ or materials used, it would be possible to alter the degree and effect of the modification to the response of an acoustic coupler.
Furthermore, plugs of different sizes, shapes, and/ or materials may be fitted with double sided adhesive pads or discs so that they may be added to, removed from, or changed in acoustic coupler air cavities for the purpose of optimising the performance, or equalizing the response, so that the acoustic coupler could be used with, for instance, different types of telephone handsets, or adapt to different line conditions.

Claims

1. An acoustic coupler (18) for transmitting and/or receiving encoded data signals over telephone lines, said acoustic coupler including data transmitting and/or receiving elements (20,28) to which a telephone handset (10) is acoustically coupled in audio frequency sound form, and in which in use a cavity (32) exists between respective telephone handset transducers and data transmitting and/or receiving transducers, characterized in that a plug (36) of material is provided in said cavity.
2. An acoustic coupler according to claim 1, characterized in that the material is semi-open pore material.
3. An acoustic coupler according to claim 2, characterized in that the material is foamed plastics material.
4. An acoustic coupler according to claim 3, characterized in that the material is resilient.
5. An acoustic coupler according to claim 4, characterized in that when said handset (10) is coupled to said acoustic coupler (18) , said plug (36) of material is deformable to fill said cavity (32) .
6. An acoustic coupler according to any preceding claim, characterized in that said plug (36) of material has an aperture (40) extending therethrough.
7. An acoustic coupler according to claim 6, characterized in that said aperture (40) is adapted to provide a passage between the respective handset and data terminal transducers.
8. An acoustic coupler according to claim 7, characterized in that the plug (36) of material is substantially cylindrical, and the aperture (40) is axial.
9. A method of linearising the transmission of data in an acoustic coupler (18) , including the step of providing a plug (36) of material according to any one of claims 1 to 8 in a cavity (32) of sai'd acoustic coupler (18).
OMPI
EP19800901635 1979-08-31 1981-03-09 Acoustic coupler cavity lineariser Withdrawn EP0034613A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU286/79 1979-08-31
AUPE028679 1979-08-31

Publications (1)

Publication Number Publication Date
EP0034613A1 true EP0034613A1 (en) 1981-09-02

Family

ID=3768245

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19800901635 Withdrawn EP0034613A1 (en) 1979-08-31 1981-03-09 Acoustic coupler cavity lineariser

Country Status (2)

Country Link
EP (1) EP0034613A1 (en)
WO (1) WO1981000656A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6374120B1 (en) * 1999-02-16 2002-04-16 Denso Corporation Acoustic guide for audio transducers
CN107454496B (en) * 2017-09-18 2019-12-20 歌尔股份有限公司 Neck belt type Bluetooth earphone

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2294048A (en) * 1940-11-08 1942-08-25 Provenzano Gaetano Telephone message broadcasting apparatus
US3299207A (en) * 1963-08-29 1967-01-17 Cooke Robert James Sound reproducer with means for attachment to a telephone handpiece
US3360071A (en) * 1965-08-02 1967-12-26 Chromalloy Corp Acoustical coupler
US3553374A (en) * 1969-03-20 1971-01-05 Digitronics Corp Acoustic coupler

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8100656A1 *

Also Published As

Publication number Publication date
WO1981000656A1 (en) 1981-03-05

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Legal Events

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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AK Designated contracting states

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STAA Information on the status of an ep patent application or granted ep patent

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18D Application deemed to be withdrawn

Effective date: 19810825

RIN1 Information on inventor provided before grant (corrected)

Inventor name: WHITBY, DAVID SCOTT