CA1200006A - Oto-laryngeal communication system - Google Patents
Oto-laryngeal communication systemInfo
- Publication number
- CA1200006A CA1200006A CA000425177A CA425177A CA1200006A CA 1200006 A CA1200006 A CA 1200006A CA 000425177 A CA000425177 A CA 000425177A CA 425177 A CA425177 A CA 425177A CA 1200006 A CA1200006 A CA 1200006A
- Authority
- CA
- Canada
- Prior art keywords
- microphone
- circuit
- ear
- transceiver
- oto
- 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
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/46—Special adaptations for use as contact microphones, e.g. on musical instrument, on stethoscope
Abstract
ABSTRACT
The invention consists in a voice transmitting system comprising:
a microphone having a high impedance, means to hold the microphone in or adjacent an outer ear of a person so as substantially to enclose air between the microphone and the tympanic membrane of the ear, and a circuit for transmitting a signal produced or modulated by the microphone in response to sound waves, if any, which are transmitted via the persons oto-laryngeal system to the tympanic membrane and propogated in the enclosed air.
The invention consists in a voice transmitting system comprising:
a microphone having a high impedance, means to hold the microphone in or adjacent an outer ear of a person so as substantially to enclose air between the microphone and the tympanic membrane of the ear, and a circuit for transmitting a signal produced or modulated by the microphone in response to sound waves, if any, which are transmitted via the persons oto-laryngeal system to the tympanic membrane and propogated in the enclosed air.
Description
TECHNIC~L FIELD OF THE INVENTION
This inven-tion relates to a c~mmunications system and more particularly to a system Eor voice transmission.
BACKGROUND ART
Voice transmitting systems employ a microphone, that is to say a -transducer whereby sound waves are caused to generate or modulate an electrical signal.
The microphone is connected to the input side of a circuit which transmits the electrical signal by wire or wireless means to a receiver. A telephone is an example of a voice transmitter in which the voice o-f a person speaking is detected by a microphone, the microphone signal is amplified and then delivered to a receiver comprising the earphone of a listener. Commonly used radio transceivers provi~e a voice transmitting syst~m on which the voice of a person speaking is detected by a microphone adapted to modulate the frequency or amplitude of a radio signal which may be detected by a receiver.
There are various circumstances in which t'ne use o~
a microphone in existant voice transmitting systems is disadvantageous. In a noisy environment the electrical signal is modulated by environmental noise as well as by the voice leading to poor communication between a person speaXing and the receiver~
A person wearing a respirator or other mask is unable to communicate by microphone unless the microphone is incorporated within the mask adding lZ~00~6 substantially to the co~t of the mask and often making the mask bulkier than need be since -the microphone must be spaced from the mouth.
In many circumstanc-es a person wishes to be mobile, to have bo-th hanas free, and to use a radio transceiver without the need to holdl a microphone before his mouth.
Sometimes, as during surveillence, it is desira~le that voice communication be p~ossible without the presence of a microphone being readily apparent.
Although emphasis has been placed on voice transmission, it is clearly desirable that the person speaking also be able to receive and hear voice communications transmittea to him.
When a person speaks sound is conveyed via his oto-laryngeal system to his ear. It has been proposed to employ an earphone for the dual purpose of producing sound waves in the ear of a wearer and as a micro~hone to detect sounds conveyed via the oto~laryngeal system of the wearer. The earphone transducers hitherto employed have a low impedance typically of 400-600 ohms at lkHz. Such earphone transducers, while having the advantage of being able to be worn beneath a mask and of permitting hands free operation have not proved satisfactory, especially when used in noisy environments.
DISCLOSURE OF THE INVENTIO~
According to one aspect the present invention consists in a voice transmitting system comprising:
:~z~o~
a microphone having a high impedance as ~erein deEined, earplug means a~apted to ~old the micro~hone in or adjacent an outer ear of a person 50 as substantially to enclose air between the microphone and the tympanic mPmbrane of the ear, ancl a circuit for transmitting a signai producea or modulated by the microphone in response to sound waves, if any, which are transmitted via the pexsons oto-laryngeal system to the tympanic membrane and propogated in the ~nclosed ai r .
By "high impedance" is meant that the microphone has an impedance equivalent to at least 1000 ohms, and preferably greater than 2000 ohms at lkFIz.
For preference the microphone is worn by means of an earplu~ individually cast for the ear of the wearer in the manner of a hearing aid earplug and is a transducer which is also operable as an earphone.
It was previously ~elieved that increasing t~e sensitivity of a microphone plugged to the oto-laryngeal system would merely aggrevate pxoblems of extraneous noise.
The present invention is based on the surprising discovery that when air is enclosed between the tympanic membrane and a sufficiently high impedance microphone, the effect of external noise and vibration is greatly reduced, and in preferred embodiments, is halved.
Apparently when a low impedance (400-800 ohms) ~2~ )6 ~ 5 --transducer is employed as a ~icrophone a high proportion o~ the detected audio energy is transmitted via bone structure and is thus subjected to noise vibrations from the general environ~en-t. It has been found that when a high impedance microphone is employed in accordance with the present invention, a high proportion oE the detected audio energy is substantially transmitted from the tympanic membrane by means of the air column in -the auditory canal and is much less influenced by vibrations in the bone which originate externally.
DESCRIPTION OF PREFERRED EMBODIMENT
By way of example only the invention will now be described with reference to -the accompanying circuit schematic diagram (FIG. 1).
The circuit is an interface circuit for use with a two way radio transceiver 5no-t shown) having connec-tors Eor external speaker and microphone.
The interface circuit of Fig. 1 comprises a high impedance transducer T, a two stage amplifier and an electronic switch and is powered by a 1.5 ~ battery.
In use terminal Al is connected to the audio output of the radio transceiver.
~ Yhen yanged switch SlB is in the "NC" position as shown in Fig. 1 an audio signal from the transceiver connected at the "audio-in" terminal Al is routed to transduc~r T via capacitor C8 and resistor Rll.
Capacitor C8 provides DC blocking and resistor R7 provides overload protection Eor transducer T which is a ~2~
type AP2000 earpiece supplied by Crystal Aid Pty. ~td., ~ustralia, having an impedance of around 2000 ohms at lkHz and developed for use as a hearing aid.
When ganged switch SWlA/SWlB is in the "NO"
position, that is to say in the "transmit" mode~ power is applied to electronic switch Ql and the two ampli~ier stages Q2 and Q3 via swiltch SlA. Transistor Ql is turned on causing the PTT ("PUSH TO TALK") line connected via terminal A3 to the associated transceiver to go low. With switch SlB in the "N0" position the audio signal Erom transclucer T is applied at the base of the first amplifier staqe Q2. Transistor Q3 provides further amplification and impedance matching.
The audio signal i5 then attenuated to the required leve] by variable resistance RVl and fed to the associated transceiver via terminal A2 "audio out"~
~ s mentioned above "Earpiece" T comprises a high impedance coil ~aving a DC resistance of about 2000 ohms and preferably higher and has a magnet moveable relative to the coil by a diaphram affixed either -to the magnet or the coil. T~e "earpiece" is thus able to function either as a microphone to modulate a signal in response to movement of the diaphram or as an earphone when fed with a modulated signal.
For preference the "earpiece" is oE a size similar to a hearing aid earpiece and is held in the ear o-f a wearer by a custom made hollow casting such as is often used to seal a hearing aid earphone to an ear. However ~L2~V~)6 the earpiece may be otherwi~e adapted '~y shape ko fit in or adjacent the ear so as to enclose air between the transducer and tympanic membrane.
Switch ~Wl serves to disconnect the audio reception line from the transceiver to the transducer when the transducer is used Eor voice transmission. Because the apparatus operates from a l.5 battery it is non-sparking and useable in hazardous environments~
Fl is a ferrite bead providing shielding. Ql, Q2 and Q3 are each type BC 549 transistors. The circuit parameters shown in Fig. l and indeed the circuit itself may be varied in ways which will be apparent to those skilled in the art from the teaching hereof.
For preference the interface circuit is adapted to be worn on the belt.
As will be apparent to those skilled in the art, ear protectors if desired, may be worn over the earpiece to further reduce extraneous noise. In other embodiments the microphone is built into ear protectors.
This inven-tion relates to a c~mmunications system and more particularly to a system Eor voice transmission.
BACKGROUND ART
Voice transmitting systems employ a microphone, that is to say a -transducer whereby sound waves are caused to generate or modulate an electrical signal.
The microphone is connected to the input side of a circuit which transmits the electrical signal by wire or wireless means to a receiver. A telephone is an example of a voice transmitter in which the voice o-f a person speaking is detected by a microphone, the microphone signal is amplified and then delivered to a receiver comprising the earphone of a listener. Commonly used radio transceivers provi~e a voice transmitting syst~m on which the voice of a person speaking is detected by a microphone adapted to modulate the frequency or amplitude of a radio signal which may be detected by a receiver.
There are various circumstances in which t'ne use o~
a microphone in existant voice transmitting systems is disadvantageous. In a noisy environment the electrical signal is modulated by environmental noise as well as by the voice leading to poor communication between a person speaXing and the receiver~
A person wearing a respirator or other mask is unable to communicate by microphone unless the microphone is incorporated within the mask adding lZ~00~6 substantially to the co~t of the mask and often making the mask bulkier than need be since -the microphone must be spaced from the mouth.
In many circumstanc-es a person wishes to be mobile, to have bo-th hanas free, and to use a radio transceiver without the need to holdl a microphone before his mouth.
Sometimes, as during surveillence, it is desira~le that voice communication be p~ossible without the presence of a microphone being readily apparent.
Although emphasis has been placed on voice transmission, it is clearly desirable that the person speaking also be able to receive and hear voice communications transmittea to him.
When a person speaks sound is conveyed via his oto-laryngeal system to his ear. It has been proposed to employ an earphone for the dual purpose of producing sound waves in the ear of a wearer and as a micro~hone to detect sounds conveyed via the oto~laryngeal system of the wearer. The earphone transducers hitherto employed have a low impedance typically of 400-600 ohms at lkHz. Such earphone transducers, while having the advantage of being able to be worn beneath a mask and of permitting hands free operation have not proved satisfactory, especially when used in noisy environments.
DISCLOSURE OF THE INVENTIO~
According to one aspect the present invention consists in a voice transmitting system comprising:
:~z~o~
a microphone having a high impedance as ~erein deEined, earplug means a~apted to ~old the micro~hone in or adjacent an outer ear of a person 50 as substantially to enclose air between the microphone and the tympanic mPmbrane of the ear, ancl a circuit for transmitting a signai producea or modulated by the microphone in response to sound waves, if any, which are transmitted via the pexsons oto-laryngeal system to the tympanic membrane and propogated in the ~nclosed ai r .
By "high impedance" is meant that the microphone has an impedance equivalent to at least 1000 ohms, and preferably greater than 2000 ohms at lkFIz.
For preference the microphone is worn by means of an earplu~ individually cast for the ear of the wearer in the manner of a hearing aid earplug and is a transducer which is also operable as an earphone.
It was previously ~elieved that increasing t~e sensitivity of a microphone plugged to the oto-laryngeal system would merely aggrevate pxoblems of extraneous noise.
The present invention is based on the surprising discovery that when air is enclosed between the tympanic membrane and a sufficiently high impedance microphone, the effect of external noise and vibration is greatly reduced, and in preferred embodiments, is halved.
Apparently when a low impedance (400-800 ohms) ~2~ )6 ~ 5 --transducer is employed as a ~icrophone a high proportion o~ the detected audio energy is transmitted via bone structure and is thus subjected to noise vibrations from the general environ~en-t. It has been found that when a high impedance microphone is employed in accordance with the present invention, a high proportion oE the detected audio energy is substantially transmitted from the tympanic membrane by means of the air column in -the auditory canal and is much less influenced by vibrations in the bone which originate externally.
DESCRIPTION OF PREFERRED EMBODIMENT
By way of example only the invention will now be described with reference to -the accompanying circuit schematic diagram (FIG. 1).
The circuit is an interface circuit for use with a two way radio transceiver 5no-t shown) having connec-tors Eor external speaker and microphone.
The interface circuit of Fig. 1 comprises a high impedance transducer T, a two stage amplifier and an electronic switch and is powered by a 1.5 ~ battery.
In use terminal Al is connected to the audio output of the radio transceiver.
~ Yhen yanged switch SlB is in the "NC" position as shown in Fig. 1 an audio signal from the transceiver connected at the "audio-in" terminal Al is routed to transduc~r T via capacitor C8 and resistor Rll.
Capacitor C8 provides DC blocking and resistor R7 provides overload protection Eor transducer T which is a ~2~
type AP2000 earpiece supplied by Crystal Aid Pty. ~td., ~ustralia, having an impedance of around 2000 ohms at lkHz and developed for use as a hearing aid.
When ganged switch SWlA/SWlB is in the "NO"
position, that is to say in the "transmit" mode~ power is applied to electronic switch Ql and the two ampli~ier stages Q2 and Q3 via swiltch SlA. Transistor Ql is turned on causing the PTT ("PUSH TO TALK") line connected via terminal A3 to the associated transceiver to go low. With switch SlB in the "N0" position the audio signal Erom transclucer T is applied at the base of the first amplifier staqe Q2. Transistor Q3 provides further amplification and impedance matching.
The audio signal i5 then attenuated to the required leve] by variable resistance RVl and fed to the associated transceiver via terminal A2 "audio out"~
~ s mentioned above "Earpiece" T comprises a high impedance coil ~aving a DC resistance of about 2000 ohms and preferably higher and has a magnet moveable relative to the coil by a diaphram affixed either -to the magnet or the coil. T~e "earpiece" is thus able to function either as a microphone to modulate a signal in response to movement of the diaphram or as an earphone when fed with a modulated signal.
For preference the "earpiece" is oE a size similar to a hearing aid earpiece and is held in the ear o-f a wearer by a custom made hollow casting such as is often used to seal a hearing aid earphone to an ear. However ~L2~V~)6 the earpiece may be otherwi~e adapted '~y shape ko fit in or adjacent the ear so as to enclose air between the transducer and tympanic membrane.
Switch ~Wl serves to disconnect the audio reception line from the transceiver to the transducer when the transducer is used Eor voice transmission. Because the apparatus operates from a l.5 battery it is non-sparking and useable in hazardous environments~
Fl is a ferrite bead providing shielding. Ql, Q2 and Q3 are each type BC 549 transistors. The circuit parameters shown in Fig. l and indeed the circuit itself may be varied in ways which will be apparent to those skilled in the art from the teaching hereof.
For preference the interface circuit is adapted to be worn on the belt.
As will be apparent to those skilled in the art, ear protectors if desired, may be worn over the earpiece to further reduce extraneous noise. In other embodiments the microphone is built into ear protectors.
Claims (8)
PRIVILEGE OR PROPERTY IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A voice transmitting system comprising:
a microphone having a high impedance as herein defined;
earplug means adapted to hold the microphone in or adjacent an outer ear of a person so as substantially to enclose air between the microphone and the tympanic membrane of the ear;
and a circuit for transmitting a signal produced or modulated by the microphone in response to sound waves, if any, which are transmitted via the persons oto-laryngeal system to the tympanic membrane and propagated in the enclosed air.
a microphone having a high impedance as herein defined;
earplug means adapted to hold the microphone in or adjacent an outer ear of a person so as substantially to enclose air between the microphone and the tympanic membrane of the ear;
and a circuit for transmitting a signal produced or modulated by the microphone in response to sound waves, if any, which are transmitted via the persons oto-laryngeal system to the tympanic membrane and propagated in the enclosed air.
2. Apparatus according to claim 1 wherein the microphone has an impedance equivalent to at least 2000 ohms at 1kHz.
3. Apparatus according to claim 1 wherein the earplug includes an earpiece custom fitted to the wearer.
4. Apparatus according to claim 2 wherein the earplug includes an earpiece custom fitted to the wearer.
5. Apparatus according to claim 3 further comprising a circuit whereby the microphone may be connected to drive a radio transceiver in a transmit mode or to receive a signal output by said transceiver in a receive mode.
6. Apparatus according to claim 4 further comprising a circuit whereby the microphone may be connected to drive a radio transceiver in a transmit mode or to receive a signal output by said transceiver in a receive mode.
7. Apparatus according to claim 5 comprising a two stage amplifier circuit and switch means which disconnect the transducer from signal reception during voice transmission.
8. Apparatus according to claim 6 comprising a two stage amplifier circuit and switch means which disconnect the transducer from signal reception during voice transmission. \
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPF3464 | 1982-04-05 | ||
| AUPF346482 | 1982-04-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1200006A true CA1200006A (en) | 1986-01-28 |
Family
ID=3769456
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000425177A Expired CA1200006A (en) | 1982-04-05 | 1983-04-05 | Oto-laryngeal communication system |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0114828A4 (en) |
| JP (1) | JPS59500744A (en) |
| AU (1) | AU552678B2 (en) |
| CA (1) | CA1200006A (en) |
| WO (1) | WO1983003733A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DK159190C (en) * | 1988-05-24 | 1991-03-04 | Steen Barbrand Rasmussen | SOUND PROTECTION FOR NOISE PROTECTED COMMUNICATION BETWEEN THE USER OF THE EARNET PROPERTY AND SURROUNDINGS |
| JPH0456531A (en) * | 1990-06-26 | 1992-02-24 | Matsushita Electric Ind Co Ltd | Voice input device |
| GB2281004A (en) * | 1993-08-11 | 1995-02-15 | Yang Chao Ming | Combined microphone/earphone |
| US9401158B1 (en) | 2015-09-14 | 2016-07-26 | Knowles Electronics, Llc | Microphone signal fusion |
| US9779716B2 (en) | 2015-12-30 | 2017-10-03 | Knowles Electronics, Llc | Occlusion reduction and active noise reduction based on seal quality |
| US9830930B2 (en) | 2015-12-30 | 2017-11-28 | Knowles Electronics, Llc | Voice-enhanced awareness mode |
| US9812149B2 (en) | 2016-01-28 | 2017-11-07 | Knowles Electronics, Llc | Methods and systems for providing consistency in noise reduction during speech and non-speech periods |
-
1983
- 1983-03-31 AU AU13770/83A patent/AU552678B2/en not_active Ceased
- 1983-03-31 EP EP19830901058 patent/EP0114828A4/en not_active Withdrawn
- 1983-03-31 JP JP58501137A patent/JPS59500744A/en active Pending
- 1983-03-31 WO PCT/AU1983/000039 patent/WO1983003733A1/en not_active Application Discontinuation
- 1983-04-05 CA CA000425177A patent/CA1200006A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| AU552678B2 (en) | 1986-06-12 |
| JPS59500744A (en) | 1984-04-26 |
| EP0114828A1 (en) | 1984-08-08 |
| WO1983003733A1 (en) | 1983-10-27 |
| AU1377083A (en) | 1983-11-04 |
| EP0114828A4 (en) | 1984-12-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |