CA1216798A - Method and device for the transmission of acoustic information as perceivable vibrations - Google Patents
Method and device for the transmission of acoustic information as perceivable vibrationsInfo
- Publication number
- CA1216798A CA1216798A CA000463332A CA463332A CA1216798A CA 1216798 A CA1216798 A CA 1216798A CA 000463332 A CA000463332 A CA 000463332A CA 463332 A CA463332 A CA 463332A CA 1216798 A CA1216798 A CA 1216798A
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- amplifier
- signal
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- pass filter
- differential frequencies
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R25/00—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception
- H04R25/60—Mounting or interconnection of hearing aid parts, e.g. inside tips, housings or to ossicles
- H04R25/604—Mounting or interconnection of hearing aid parts, e.g. inside tips, housings or to ossicles of acoustic or vibrational transducers
- H04R25/606—Mounting or interconnection of hearing aid parts, e.g. inside tips, housings or to ossicles of acoustic or vibrational transducers acting directly on the eardrum, the ossicles or the skull, e.g. mastoid, tooth, maxillary or mandibular bone, or mechanically stimulating the cochlea, e.g. at the oval window
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F11/00—Methods or devices for treatment of the ears or hearing sense; Non-electric hearing aids; Methods or devices for enabling ear patients to achieve auditory perception through physiological senses other than hearing sense; Protective devices for the ears, carried on the body or in the hand
- A61F11/04—Methods or devices for enabling ear patients to achieve auditory perception through physiological senses other than hearing sense, e.g. through the touch sense
- A61F11/045—Methods or devices for enabling ear patients to achieve auditory perception through physiological senses other than hearing sense, e.g. through the touch sense using mechanical stimulation of nerves
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09B—EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
- G09B21/00—Teaching, or communicating with, the blind, deaf or mute
- G09B21/009—Teaching or communicating with deaf persons
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- Health & Medical Sciences (AREA)
- Engineering & Computer Science (AREA)
- General Health & Medical Sciences (AREA)
- Otolaryngology (AREA)
- Physics & Mathematics (AREA)
- Biomedical Technology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Neurology (AREA)
- Acoustics & Sound (AREA)
- Educational Technology (AREA)
- Biophysics (AREA)
- Neurosurgery (AREA)
- General Physics & Mathematics (AREA)
- Signal Processing (AREA)
- Educational Administration (AREA)
- Business, Economics & Management (AREA)
- Physiology (AREA)
- Audiology, Speech & Language Pathology (AREA)
- Theoretical Computer Science (AREA)
- Psychology (AREA)
- Heart & Thoracic Surgery (AREA)
- Vascular Medicine (AREA)
- Animal Behavior & Ethology (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
- Amplifiers (AREA)
- Piezo-Electric Transducers For Audible Bands (AREA)
- Circuit For Audible Band Transducer (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The invention relates to methods and devices for the transmission of acoustic information as perceivable vibrations. The invention provides for a derivation of signals from the high-frequency components by forming differential frequencies. In an instrument suited for this purpose the information can be acquired by a microphone and fed to a vibrator via a preamplifier and an output amplifier, there branching off between the amplifier components via a line a signal channel containing a high-pass filter, a stage of nonlinear characteristic, a low-pass filter and another amplifier which is connected to the output amplifier and the volume control of the instrument. The invention is particularly useful for persons with severe or even complete hearing loss to make it easier to learn to speak and to read lips.
The invention relates to methods and devices for the transmission of acoustic information as perceivable vibrations. The invention provides for a derivation of signals from the high-frequency components by forming differential frequencies. In an instrument suited for this purpose the information can be acquired by a microphone and fed to a vibrator via a preamplifier and an output amplifier, there branching off between the amplifier components via a line a signal channel containing a high-pass filter, a stage of nonlinear characteristic, a low-pass filter and another amplifier which is connected to the output amplifier and the volume control of the instrument. The invention is particularly useful for persons with severe or even complete hearing loss to make it easier to learn to speak and to read lips.
Description
~2~
BACKGRûUND 0~ THE INNENTION
The invention relates to methods for the transmission of acoustic information as perceivable vibrations, and to devices for S the implementation of these methods. Methods and devices of this general type are known from US Patent 4,289,~35.
In vibratory transmission of acoustic signals such as a Yoice, the skin (e.g. at the wrist) is mechanically stimulatea. The perception range of the skin for such mechano-cutane stimuli starts at rather low frequencies, approximately on the order of magnitude of 20 Hz. But the upper range (about 1.2 kHz) is relatively low compared to the overall range of audible frequencies, (see e.g.
Funkschau 11 (198~) page 53). Unvoiced consonants such as s, sch, ch, which acoustically predominantly have frequencies hi~her than 2 kHz, can therefore not be made perceivable by linear ~ransmission by skin stimulation. In known instruments, the use of a microphone is resorted to which is held close to the mouth so that the air blown out of the mouth onto the microphone diaphragm generates a rumbling noise characteristic for unvoiced sounds, which can then be made perceivable.
In a portable device for the transmission of acoustic signals as vibrations, e.g. in instruments which are to be used as communication aids, i.e. a kind of hearing aia7 talking into an extremely close microphone is not possible, first for cosmetlc reasons and secondly because unvoiced sounds from both nearby an~
further away are to be transmitted. In such instruments, the microphone is permanently joined to the amplifier unit as in conventional pocket hearing aids, or else the microphone is attachable to clothlng and located approximately 2û to 30 cm away from the mouth.
Known from US Patent No. 4,289,935 is an instrument in which, in order to obtain good intelligibility and simplification of the equipmental design otherwise usual in hearing aids for the extremely hearing impaired, the signals to be transmitted are divided into S several frequency bands, the division being used to modulate alternating voltages (sounds) which are then conduzted, together with the signals coming from the microphone, to a receiver or else to a vibrator (vibrotactile stimulus generator) after amplification. For unvoiced sound this requires a switching from the line spectrum to a noise spectrum or a line spectrum. The vocoder provided, i.e. the high cost associated with such a conversion, has so far been a hindrance to its introductlon ln the hearing aid industry.
It is an object of the invention to provide a method and devices for the implementation of this method which will work satisfactorily under the usual hearing aid conditions.
SUMMARY OF THE INVENTI~N
The invention provides for a transformation of the characteristic high frequency of the sibliants into the range of perceivable frequencies. To do this, the acoustic signal can be transformed in a microphone into a sequence of electrical signals and fed to the vibrator amplified in the usual manner~ while the signals are also branched off from the transmission path, and the high frequencies corresponding to the sibliants are separated from them by means of filters. These frequency components, characteristic for the unvoiced sounds, are then fed to an intermodulation amplifier so as to obtain sum and differential products of the frequency components. The result of the intermodulation amplification, i.e. the sum and differential frequencies of the unvoiced sounds, is finally returned to the conventionally amplified signal. To avoid overloa~iny the output amplifier with the high-frequency sum frequencies, it is expedient to isolate the low-frequency components below lOû Hz which can ~e made perceivable by a vibrator and to pass only them on. There is finally obtained, besides the perceivable vibrations occurriny in known instruments, a vibration series characteristic for the unvoiced sounds. This requires only the acquisition of the sibliants themselves, and no blowing noise at the microphone, so that an unequivncal identification of the sibliants becomes possible also in portable instruments. On the other hand, the implementation of the method merely requires a design in which a few simple components operable ~ith the usual hearing aid batteries are sufficient.
In one embodiment of the invention the acoustic signals a~e received by a microphone and amplifie~ in a preamplifier that has a limiter. The limiter assures that the signal at the preamplifier output is not distorted due to harmonics originating at the limiter which could artificially simulate the presence of unvoiced soun~s.
The signal thus amplified then reaches the vi~rator directly via a volume control and output amplifier.
For the transformation of the high frequencies above 2 kHz which are characteristic of unvoiced sounds, the voice signal is branched off after the preamplifier and filtered first by a high-pass filter. A frequency transfer at the filter limit of 12 dB/octave suffices because the desired effect is clearly achieved at relatively little cost. A frequency band characteristic for the further processing of the unvoiced sounds is thus obtained by isolating the frequencies approximately 2 kHz and higher. The frequency components contained in the band are not discrete spectral lines, but rather resemble a high-pass filtered, wide band noise signal (e.g. high-pass filtered white noise). But the noise present contains nevertheless a frequency distribution characteristic of the respective sibiiants.
In an amplifier stage succeeding the high~pass filter the signal is brought to a level sufficient for the modulation in the subsequent intermodulation stage to be such that a linear signal is obtained over as wide a range as possible. In this stage, which has nonlinear characteristics, intermodulation products are produced from the previously filtered noise, i.e. the high-frequency components at the input of the intermodulation stage occur at its output additionally as sum and differential frequencies. The nonlinear characteristic of the intermodulation stage may correspono to a quadratic transfer function. This is advantageous because only sum and differential frequencies of the fundamentals are produced, but not sum and differential frequencies of multiples of the fundamentals. This would render differentiation of the unvoiced sounds more difficult.
s Some of the differential frequencies fall into the low-frequency range below 1 kHz which can be made perceivable by means of a vibrator. Therefore, these frequencies are expediently separated, as mentioned above, in a low-pass filter, for which a second-order filter also suffices. The signal thus obtained can then be matched to the level of the original signal in an amplifier stage and added to this original signal in a summation stage so that the vibrator receiYes, via the loudspeaker and the output stage, a signal mix containing the transformed frequencies of the sibilants, besides more frequencies ~hich are present in the simple amplification.
Usable as hiyh and low-pass filters in the branched signal p~tns are any active or passive second-order RC filters. THe limit frequency of the hlgh-pass filter should be between 2 kHz to 4 kHz.
Characteristic frequency components of the unvoiced soun~s are present in the voice frequency spectrum from 2 kHz up. At a limit frequency higher than 4 kHz the various unvoiced sounds may no longer be differentiable. A low-pass filter is not absolutely necessary because the perceptibility ranye of the skin ends at about 1 kHz, but such a filter is useful to prevent overloading the output stage with differential frequencies outside of the required frequency range. The suitable limit frequency ranges from about 200 Hz to 1 kHz. The transmission of the differential sounds in the range up to about 2Q0 Hz contains the important information (comparable to the blow noises of a microphone near the mouth) and must be able to take place. The transmission of frequencies higher than 1 kHz is unnecessary because they are outside of tne perceptibility range of the skin.
.. ......
To generate the intermodulation siynal, a stage can be used which contains an operational amplifier that feeds the signal to a diode~ There the bulk of the intermodulation signal is generated in that a multiplication of the sum of the frequencies by the nonlinear characteristic of the diode takes place. Since a desired dynamic range, iOe. one within the operating range of the diode, can lead to overproportionally great output signals when strong signals are modulated, it is expedient to compensate this rise of the characteristic by diodes poled in opposition to each other. A linear characteristic of the intermodulation products is achievable by appropriately choosing the rest of the components.
Thus, in accordance with a broad aspect of the invention, there is provided a method for transmitting acoustic information, comprising: converting the information into an electrical signal; isola-ting high-frequency components of the signal; forming differential frequencies of said components;
and transmitting said differential frequencies to a vibrator.
In accordance with ano-ther broad aspect of the invention there is provided a device for transmitting acous-tic information, comprising: means for converting -the information into an electrical signal; means for isolating high-frequency components of the signal; means for forming differential frequencies of said high-frequency components; and means for transmitting said differential frequencies to a vibrator.
In accordance with another broad aspect of the invention there is provided a device for transmitting acoustic . ~
~6~
information, comprising: means for convertiny the information into an electrical signal; means for isolatiny high-frequency components of the signal; an intermodulation means having a non-linear transfer function for forming sum and differential frequencies of said high-frequencies components; means for isolating the differential frequencies; and means for transmitting said differential frequencies to a vibrator.
Exemplary and non-limiting preferred embodiments of the invention are shown in the drawings, in which:
Fig. 1 is a basic block diagram of a preferred embodiment of the invention; and Fig. 2 an example of the circui-t for the intermodulation stage contained in Fig. 1.
-6a-~.
DETAILED DESCRIPTION GF_PREFER~ED EM8CUIMENTS
1 in Fig. 1 is a microphone connected to a limiter amplifier 2.
From it, a ~ine 3 goes to a headphone 6 via a volume control 4 and an output amplifier 5. There is another connection of the preamplifier 2 to a vibrator 10 via another line 7, a sum,nation circuit 18 and toth a volume control 8 and output amplifier 9.
Finally a line 11 is present which leads through a switch 12 to a high-pass filter 13 which only passes frequencies above 2 kHz.
These frequencies then reach an amplifier 1~ whence they arrlve at an interModulation amplifier 15. Tne output signals of the intermodulation amplifier 15 are then fed via a low-pass filter 16 and an amplifier 17 to a summation circuit 18 through which the signal branched off by means of line 11 and processed in the elements 13 through 17 is reunited with the original siynal transmitted by line 7.
The signal path between the microphone 1 and the headphone 6 corresponds to that in conventional hearing aids. The signal is acquired by the microphone 1, transformed lnto a sequence of electrical signals and amplified in the preamplifier 2. After having passed the volume control 5, this signal reaches the output amplifier 5 whence the headphone 6 is then activated. This branch with its components 3 through 6 can be omitted, if an instrument is involved intended to serve persons with complete loss of hearing; it then suffices to feed the signal processed in the preamplifier 2 directly via the line 7 and a volume control 8 to an output amplifier 9 whence the vibrator 10 is operated.
In the instrument the signal is branched off between the preamplifier 2 and the volume control 8 via a line 11. This signal can then be connected to the processing stages 13 through 17 via the switch 12, the processed signal then being added again in the summation circuit 18 to the original signal path flowing through line 7.
When the switch 12 is closed, the high-pass filter 13 whose limit frequency is near 2 kHz isolates the signal components above the limit frequency and then the signal is brought in the amplifier 14 to a level sufficient to drive the intermodulation stage 15. In the low pass filter 1~ the summation signals of stage 15 are then separated and, because of the 4ûO Hz limit frequency of filter 16, only those components are passed which can be made perceivable in the vibrator lOo Finally, these components are brought in the amplifier 17 to a level which makes it possible without interference to add in summation circuit 18 the signals processed between 13 and 17 to the original flow in line 7 again.
Used as high-pass filter 13 is an active second-order RC filter whose limit frequency is near 2 kHz, and as low-pass filter 16 a second order filter with a limit frequency near 400 Hz.
According to Fig. 2, the intermodulation stage 15 has after its input 20 a resistor 21, an operational amplifier 22, a ~iode 23 and a capacitor 24 before the connection ends at the outp~t 25. Between the dioae 23 and the capacitor 24 is a branch to ground at the chassis via a resistor 2~. Between the amplifier 22 and the diode 23 is a connection 29 to the positive power supply via resistor 28.
. ~, ~23,~
~he amplifier 22 has a cor~ection 34 to the positive and a connection 3~ to the negative power supply.
The output and the inverting input of operational ampli-fier 22 are bridged via a resistor 30. Also present is another bridge of the amplifier 22 via a connection containing a resistor 31 and dlodes 32 and 33 which are in parallel and connected with opposed polarities. The other input of the amplifier 22 is connected to ground at the chassis via a resistor 36.
For an instrument according to Fig. 1 which is operated with a power source of 4 to 6 V, the intermodulation amplifier 15 is expediently designed with an operational amplifier 22 characterized by a minimum supply voltage of 3 V and an upper limit frequency of 20 kHz at 30 dB amplification, and equipped with a 10 kOhm resistor 21, a 100 kOhm resistor 26, a 3.3 kOhm reslstor 28, a 330 kOhm resistor 30 and a 22 kOhm resistor 31.
The capacitance of capacitor 24 is l ~f. The diodes 23, 32) 33 are commercial small signal silicon diodes with approximately 400 mW power ratings.
When the components of the intermodulation amplifier 15 are designed as described above, the resistors 21 together effect a 33 dB (or approximately 30 dB) amplification of the amplifier 22. Because of the nonlinear, partly square characteristic, the diode 23 furnishes the actual intermodulation signal which is then coupled out to a load resistance (not shown) by the capa-citor 24. In order to keep the intermodulation signal as great as possible, this load resistance should be in the order of magniture of 100 kOhm. By connecting the positive supply vol-tage at 29 via the resistor 28 it is achieved that the ampli-fier 22 operates in its proper operating range. Connecting the resistor 31 in series with the oppositely poled diodes 32 and 33 results in the compensa-tion of the overproportional rise of the transmission characteristic of the intermodulation amplifier at higher levels, thus linearizing the transfer characteristic.
Those skilled in the art will undPrstand that changes can be made in the preferred embodiments here described, and that these embodiments can be used for other ,ourposes. Such changes and uses are within the scope of the invention, which is limited only by the S claims which follow.
BACKGRûUND 0~ THE INNENTION
The invention relates to methods for the transmission of acoustic information as perceivable vibrations, and to devices for S the implementation of these methods. Methods and devices of this general type are known from US Patent 4,289,~35.
In vibratory transmission of acoustic signals such as a Yoice, the skin (e.g. at the wrist) is mechanically stimulatea. The perception range of the skin for such mechano-cutane stimuli starts at rather low frequencies, approximately on the order of magnitude of 20 Hz. But the upper range (about 1.2 kHz) is relatively low compared to the overall range of audible frequencies, (see e.g.
Funkschau 11 (198~) page 53). Unvoiced consonants such as s, sch, ch, which acoustically predominantly have frequencies hi~her than 2 kHz, can therefore not be made perceivable by linear ~ransmission by skin stimulation. In known instruments, the use of a microphone is resorted to which is held close to the mouth so that the air blown out of the mouth onto the microphone diaphragm generates a rumbling noise characteristic for unvoiced sounds, which can then be made perceivable.
In a portable device for the transmission of acoustic signals as vibrations, e.g. in instruments which are to be used as communication aids, i.e. a kind of hearing aia7 talking into an extremely close microphone is not possible, first for cosmetlc reasons and secondly because unvoiced sounds from both nearby an~
further away are to be transmitted. In such instruments, the microphone is permanently joined to the amplifier unit as in conventional pocket hearing aids, or else the microphone is attachable to clothlng and located approximately 2û to 30 cm away from the mouth.
Known from US Patent No. 4,289,935 is an instrument in which, in order to obtain good intelligibility and simplification of the equipmental design otherwise usual in hearing aids for the extremely hearing impaired, the signals to be transmitted are divided into S several frequency bands, the division being used to modulate alternating voltages (sounds) which are then conduzted, together with the signals coming from the microphone, to a receiver or else to a vibrator (vibrotactile stimulus generator) after amplification. For unvoiced sound this requires a switching from the line spectrum to a noise spectrum or a line spectrum. The vocoder provided, i.e. the high cost associated with such a conversion, has so far been a hindrance to its introductlon ln the hearing aid industry.
It is an object of the invention to provide a method and devices for the implementation of this method which will work satisfactorily under the usual hearing aid conditions.
SUMMARY OF THE INVENTI~N
The invention provides for a transformation of the characteristic high frequency of the sibliants into the range of perceivable frequencies. To do this, the acoustic signal can be transformed in a microphone into a sequence of electrical signals and fed to the vibrator amplified in the usual manner~ while the signals are also branched off from the transmission path, and the high frequencies corresponding to the sibliants are separated from them by means of filters. These frequency components, characteristic for the unvoiced sounds, are then fed to an intermodulation amplifier so as to obtain sum and differential products of the frequency components. The result of the intermodulation amplification, i.e. the sum and differential frequencies of the unvoiced sounds, is finally returned to the conventionally amplified signal. To avoid overloa~iny the output amplifier with the high-frequency sum frequencies, it is expedient to isolate the low-frequency components below lOû Hz which can ~e made perceivable by a vibrator and to pass only them on. There is finally obtained, besides the perceivable vibrations occurriny in known instruments, a vibration series characteristic for the unvoiced sounds. This requires only the acquisition of the sibliants themselves, and no blowing noise at the microphone, so that an unequivncal identification of the sibliants becomes possible also in portable instruments. On the other hand, the implementation of the method merely requires a design in which a few simple components operable ~ith the usual hearing aid batteries are sufficient.
In one embodiment of the invention the acoustic signals a~e received by a microphone and amplifie~ in a preamplifier that has a limiter. The limiter assures that the signal at the preamplifier output is not distorted due to harmonics originating at the limiter which could artificially simulate the presence of unvoiced soun~s.
The signal thus amplified then reaches the vi~rator directly via a volume control and output amplifier.
For the transformation of the high frequencies above 2 kHz which are characteristic of unvoiced sounds, the voice signal is branched off after the preamplifier and filtered first by a high-pass filter. A frequency transfer at the filter limit of 12 dB/octave suffices because the desired effect is clearly achieved at relatively little cost. A frequency band characteristic for the further processing of the unvoiced sounds is thus obtained by isolating the frequencies approximately 2 kHz and higher. The frequency components contained in the band are not discrete spectral lines, but rather resemble a high-pass filtered, wide band noise signal (e.g. high-pass filtered white noise). But the noise present contains nevertheless a frequency distribution characteristic of the respective sibiiants.
In an amplifier stage succeeding the high~pass filter the signal is brought to a level sufficient for the modulation in the subsequent intermodulation stage to be such that a linear signal is obtained over as wide a range as possible. In this stage, which has nonlinear characteristics, intermodulation products are produced from the previously filtered noise, i.e. the high-frequency components at the input of the intermodulation stage occur at its output additionally as sum and differential frequencies. The nonlinear characteristic of the intermodulation stage may correspono to a quadratic transfer function. This is advantageous because only sum and differential frequencies of the fundamentals are produced, but not sum and differential frequencies of multiples of the fundamentals. This would render differentiation of the unvoiced sounds more difficult.
s Some of the differential frequencies fall into the low-frequency range below 1 kHz which can be made perceivable by means of a vibrator. Therefore, these frequencies are expediently separated, as mentioned above, in a low-pass filter, for which a second-order filter also suffices. The signal thus obtained can then be matched to the level of the original signal in an amplifier stage and added to this original signal in a summation stage so that the vibrator receiYes, via the loudspeaker and the output stage, a signal mix containing the transformed frequencies of the sibilants, besides more frequencies ~hich are present in the simple amplification.
Usable as hiyh and low-pass filters in the branched signal p~tns are any active or passive second-order RC filters. THe limit frequency of the hlgh-pass filter should be between 2 kHz to 4 kHz.
Characteristic frequency components of the unvoiced soun~s are present in the voice frequency spectrum from 2 kHz up. At a limit frequency higher than 4 kHz the various unvoiced sounds may no longer be differentiable. A low-pass filter is not absolutely necessary because the perceptibility ranye of the skin ends at about 1 kHz, but such a filter is useful to prevent overloading the output stage with differential frequencies outside of the required frequency range. The suitable limit frequency ranges from about 200 Hz to 1 kHz. The transmission of the differential sounds in the range up to about 2Q0 Hz contains the important information (comparable to the blow noises of a microphone near the mouth) and must be able to take place. The transmission of frequencies higher than 1 kHz is unnecessary because they are outside of tne perceptibility range of the skin.
.. ......
To generate the intermodulation siynal, a stage can be used which contains an operational amplifier that feeds the signal to a diode~ There the bulk of the intermodulation signal is generated in that a multiplication of the sum of the frequencies by the nonlinear characteristic of the diode takes place. Since a desired dynamic range, iOe. one within the operating range of the diode, can lead to overproportionally great output signals when strong signals are modulated, it is expedient to compensate this rise of the characteristic by diodes poled in opposition to each other. A linear characteristic of the intermodulation products is achievable by appropriately choosing the rest of the components.
Thus, in accordance with a broad aspect of the invention, there is provided a method for transmitting acoustic information, comprising: converting the information into an electrical signal; isola-ting high-frequency components of the signal; forming differential frequencies of said components;
and transmitting said differential frequencies to a vibrator.
In accordance with ano-ther broad aspect of the invention there is provided a device for transmitting acous-tic information, comprising: means for converting -the information into an electrical signal; means for isolating high-frequency components of the signal; means for forming differential frequencies of said high-frequency components; and means for transmitting said differential frequencies to a vibrator.
In accordance with another broad aspect of the invention there is provided a device for transmitting acoustic . ~
~6~
information, comprising: means for convertiny the information into an electrical signal; means for isolatiny high-frequency components of the signal; an intermodulation means having a non-linear transfer function for forming sum and differential frequencies of said high-frequencies components; means for isolating the differential frequencies; and means for transmitting said differential frequencies to a vibrator.
Exemplary and non-limiting preferred embodiments of the invention are shown in the drawings, in which:
Fig. 1 is a basic block diagram of a preferred embodiment of the invention; and Fig. 2 an example of the circui-t for the intermodulation stage contained in Fig. 1.
-6a-~.
DETAILED DESCRIPTION GF_PREFER~ED EM8CUIMENTS
1 in Fig. 1 is a microphone connected to a limiter amplifier 2.
From it, a ~ine 3 goes to a headphone 6 via a volume control 4 and an output amplifier 5. There is another connection of the preamplifier 2 to a vibrator 10 via another line 7, a sum,nation circuit 18 and toth a volume control 8 and output amplifier 9.
Finally a line 11 is present which leads through a switch 12 to a high-pass filter 13 which only passes frequencies above 2 kHz.
These frequencies then reach an amplifier 1~ whence they arrlve at an interModulation amplifier 15. Tne output signals of the intermodulation amplifier 15 are then fed via a low-pass filter 16 and an amplifier 17 to a summation circuit 18 through which the signal branched off by means of line 11 and processed in the elements 13 through 17 is reunited with the original siynal transmitted by line 7.
The signal path between the microphone 1 and the headphone 6 corresponds to that in conventional hearing aids. The signal is acquired by the microphone 1, transformed lnto a sequence of electrical signals and amplified in the preamplifier 2. After having passed the volume control 5, this signal reaches the output amplifier 5 whence the headphone 6 is then activated. This branch with its components 3 through 6 can be omitted, if an instrument is involved intended to serve persons with complete loss of hearing; it then suffices to feed the signal processed in the preamplifier 2 directly via the line 7 and a volume control 8 to an output amplifier 9 whence the vibrator 10 is operated.
In the instrument the signal is branched off between the preamplifier 2 and the volume control 8 via a line 11. This signal can then be connected to the processing stages 13 through 17 via the switch 12, the processed signal then being added again in the summation circuit 18 to the original signal path flowing through line 7.
When the switch 12 is closed, the high-pass filter 13 whose limit frequency is near 2 kHz isolates the signal components above the limit frequency and then the signal is brought in the amplifier 14 to a level sufficient to drive the intermodulation stage 15. In the low pass filter 1~ the summation signals of stage 15 are then separated and, because of the 4ûO Hz limit frequency of filter 16, only those components are passed which can be made perceivable in the vibrator lOo Finally, these components are brought in the amplifier 17 to a level which makes it possible without interference to add in summation circuit 18 the signals processed between 13 and 17 to the original flow in line 7 again.
Used as high-pass filter 13 is an active second-order RC filter whose limit frequency is near 2 kHz, and as low-pass filter 16 a second order filter with a limit frequency near 400 Hz.
According to Fig. 2, the intermodulation stage 15 has after its input 20 a resistor 21, an operational amplifier 22, a ~iode 23 and a capacitor 24 before the connection ends at the outp~t 25. Between the dioae 23 and the capacitor 24 is a branch to ground at the chassis via a resistor 2~. Between the amplifier 22 and the diode 23 is a connection 29 to the positive power supply via resistor 28.
. ~, ~23,~
~he amplifier 22 has a cor~ection 34 to the positive and a connection 3~ to the negative power supply.
The output and the inverting input of operational ampli-fier 22 are bridged via a resistor 30. Also present is another bridge of the amplifier 22 via a connection containing a resistor 31 and dlodes 32 and 33 which are in parallel and connected with opposed polarities. The other input of the amplifier 22 is connected to ground at the chassis via a resistor 36.
For an instrument according to Fig. 1 which is operated with a power source of 4 to 6 V, the intermodulation amplifier 15 is expediently designed with an operational amplifier 22 characterized by a minimum supply voltage of 3 V and an upper limit frequency of 20 kHz at 30 dB amplification, and equipped with a 10 kOhm resistor 21, a 100 kOhm resistor 26, a 3.3 kOhm reslstor 28, a 330 kOhm resistor 30 and a 22 kOhm resistor 31.
The capacitance of capacitor 24 is l ~f. The diodes 23, 32) 33 are commercial small signal silicon diodes with approximately 400 mW power ratings.
When the components of the intermodulation amplifier 15 are designed as described above, the resistors 21 together effect a 33 dB (or approximately 30 dB) amplification of the amplifier 22. Because of the nonlinear, partly square characteristic, the diode 23 furnishes the actual intermodulation signal which is then coupled out to a load resistance (not shown) by the capa-citor 24. In order to keep the intermodulation signal as great as possible, this load resistance should be in the order of magniture of 100 kOhm. By connecting the positive supply vol-tage at 29 via the resistor 28 it is achieved that the ampli-fier 22 operates in its proper operating range. Connecting the resistor 31 in series with the oppositely poled diodes 32 and 33 results in the compensa-tion of the overproportional rise of the transmission characteristic of the intermodulation amplifier at higher levels, thus linearizing the transfer characteristic.
Those skilled in the art will undPrstand that changes can be made in the preferred embodiments here described, and that these embodiments can be used for other ,ourposes. Such changes and uses are within the scope of the invention, which is limited only by the S claims which follow.
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for transmitting acoustic information, comprising:
converting the information into an electrical signal;
isolating high-frequency components of the signal;
forming differential frequencies of said components;
and transmitting said differential frequencies to a vibrator.
converting the information into an electrical signal;
isolating high-frequency components of the signal;
forming differential frequencies of said components;
and transmitting said differential frequencies to a vibrator.
2. The method of claim 1, wherein said forming step comprises the step of passing said components through a stage having a non-linear transfer function and the step of isolating differential frequencies in the output signal of said stage.
3. The method of claim 2, wherein the transfer function is quadratic.
4. The method of claim 1, wherein said electrical signal is amplified in a preamplifier and an output amplifier which is equipped with a volume control and is connected to a vibrator which produces tactile vibrations, wherein said isolating step comprises high-frequency filtering the signal after the output of the preamplifier, wherein said forming step comprises the steps of forming sum and differential frequencies and isolating the differential frequencies, and wherein said transmitting step comprises the steps of equalizing said sum and differential frequencies with the signal and adding them thereto before the input of the output amplifier.
5. A device for carrying out the method of claim 4, comprising:
a microphone;
the preamplifier connected to the microphone;
the output amplifier driven by the preamplifier;
a vibrator driven by the output amplifier; and a signal branch connected between the preamplifier and the output amplifier, the signal branch com-prising a high-pass filter connected to the pre-amplifier, a second amplifier connected after the high-pass filter, a stage having a nonlinear transfer function and being driven by the second amplifier, a low-pass filter driven by said stage, and a third amplifier driven by said low-pass filter.
a microphone;
the preamplifier connected to the microphone;
the output amplifier driven by the preamplifier;
a vibrator driven by the output amplifier; and a signal branch connected between the preamplifier and the output amplifier, the signal branch com-prising a high-pass filter connected to the pre-amplifier, a second amplifier connected after the high-pass filter, a stage having a nonlinear transfer function and being driven by the second amplifier, a low-pass filter driven by said stage, and a third amplifier driven by said low-pass filter.
6. The device of claim 5, wherein said stage comprises an operational amplifier and a diode connected to the output of the operational amplifier.
7. The device of claim 6, further including a feedback loop comprising a resistor and two diodes, the diodes being connected with opposite polarities in a parallel network and the network being connected in series with the resistor.
8. The device of claim 6, further comprising an output capacitor connected to the diode, a first resistor connected between ground and a common junction point of the diode and capacitor, and a second resistor with one end connected to a power supply and another end connected after the operational amplifier and before the capacitor.
9. The device of claim 5, wherein the high-pass filter has a cutoff frequency between 2 kHz and 4kHz and the low-pass filter has a cutoff frequency between 200 Hz and 1 kHz.
10. A device for transmitting acoustic information, com-prising:
means for converting the information into an electrical signal;
means for isolating high-frequency components of the signal;
means for forming differential frequencies of said high-frequency components; and means for transmitting said differential frequencies to a vibrator.
means for converting the information into an electrical signal;
means for isolating high-frequency components of the signal;
means for forming differential frequencies of said high-frequency components; and means for transmitting said differential frequencies to a vibrator.
11. A device for transmitting acoustic information, comprising:
means for converting the information into an electrical signal;
means for isolating high-frequency components of the signal;
an intermodulation means having a non-linear transfer function for forming sum and differential frequencies of said high-frequencies components;
means for isolating the differential frequencies;
and means for transmitting said differential frequencies to a vibrator.
means for converting the information into an electrical signal;
means for isolating high-frequency components of the signal;
an intermodulation means having a non-linear transfer function for forming sum and differential frequencies of said high-frequencies components;
means for isolating the differential frequencies;
and means for transmitting said differential frequencies to a vibrator.
12. A device according to claim 11, wherein said transfer function is quadratic.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3333776.4 | 1983-09-19 | ||
| DE3333776A DE3333776A1 (en) | 1983-09-19 | 1983-09-19 | METHOD AND DEVICE FOR TRANSMITTING ACOUSTIC INFORMATION AS A FEELABLE VIBRATION |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1216798A true CA1216798A (en) | 1987-01-20 |
Family
ID=6209470
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000463332A Expired CA1216798A (en) | 1983-09-19 | 1984-09-17 | Method and device for the transmission of acoustic information as perceivable vibrations |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0141953B1 (en) |
| JP (1) | JPS6087599A (en) |
| AT (1) | ATE31375T1 (en) |
| CA (1) | CA1216798A (en) |
| DE (2) | DE3333776A1 (en) |
| DK (1) | DK442884A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2764733C1 (en) * | 2021-04-19 | 2022-01-20 | Александр Сергеевич Клемёнов | Device for the development of hearing and speech in the cloth-eared and deaf |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH089990Y2 (en) * | 1985-07-31 | 1996-03-21 | 三菱電機株式会社 | Range expander |
| DE4117694C2 (en) * | 1991-05-29 | 1999-01-07 | Blindeninstitutsstiftung | Therapy device for the disabled |
| DE29710611U1 (en) * | 1997-06-18 | 1997-09-11 | Auric Hoersysteme Gmbh & Co Kg | Signaling device for medical devices |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE643118A (en) * | 1963-02-14 | 1964-05-15 | ||
| GB1340105A (en) * | 1971-06-08 | 1973-12-12 | Nat Res Dev | Aids for deaf persons |
| DK382877A (en) * | 1976-09-03 | 1978-03-04 | L Joncheray | PROCEDURE AND APPLIANCE FOR EDUCATION AND REHABILITATION OF DEEP HEAVY HEARINGS |
| DE2908999C2 (en) * | 1979-03-08 | 1982-06-09 | Siemens AG, 1000 Berlin und 8000 München | Method for generating acoustic speech signals which are understandable for the extremely hard of hearing and device for carrying out this method |
| FR2469039A1 (en) * | 1979-10-29 | 1981-05-08 | Audio Psycho Phonologie | Variable frequency response audio amplifier - has series of switchable filters to provide constant output for audiometry |
| DK153350B (en) * | 1981-10-20 | 1988-07-04 | Craigwell Ind Ltd | Hearing aid |
-
1983
- 1983-09-19 DE DE3333776A patent/DE3333776A1/en not_active Withdrawn
-
1984
- 1984-09-05 AT AT84110565T patent/ATE31375T1/en active
- 1984-09-05 EP EP84110565A patent/EP0141953B1/en not_active Expired
- 1984-09-05 DE DE8484110565T patent/DE3468081D1/en not_active Expired
- 1984-09-17 CA CA000463332A patent/CA1216798A/en not_active Expired
- 1984-09-17 JP JP59194524A patent/JPS6087599A/en active Pending
- 1984-09-18 DK DK442884A patent/DK442884A/en not_active Application Discontinuation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2764733C1 (en) * | 2021-04-19 | 2022-01-20 | Александр Сергеевич Клемёнов | Device for the development of hearing and speech in the cloth-eared and deaf |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0141953B1 (en) | 1987-12-09 |
| DK442884D0 (en) | 1984-09-18 |
| DK442884A (en) | 1985-03-20 |
| ATE31375T1 (en) | 1987-12-15 |
| DE3333776A1 (en) | 1985-04-18 |
| JPS6087599A (en) | 1985-05-17 |
| DE3468081D1 (en) | 1988-01-21 |
| EP0141953A1 (en) | 1985-05-22 |
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |