EP0250679A2
Expired / Lapsed
EP
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Programmable sound reproducing system
Assignee: AUDIMAX Corp
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Filing: 1986-10-07
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Granted: —
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Expires: 2006-10-07
Abstract
Abstract In a hearing aid system, selected optimum parameter values are programmed into an electronically erasable, programmable read-only memory (EEPROM) (84) which supplies coefficients to a programmable filter (64) and amplitude limiter (67) in the hearing aid so as to cause the hearing aid to adjust automatically to the optimum set of parameter values for the speech level, room reverberation, and type of background noise then obtaining. The programmable filter may be a digital equivalent of a tapped delay line in which each delayed sample is multiplied by a weighting coefficient, and the sum of the weighted samples generates a desired electro-acoustic characteristic; or a tapped analog delay line in which the sum of the weighted outputs of the taps generates the desired characteristics. Acoustical feedback is reduced by an electrical feedback path in the hearing aid which is matched in both amplitude and phase to the acoustic feedback path, the two feedback signals being subtracted so as to cancel each other. Alternatively, a single filter in the forward path may be used for this purpose with a transmission characteristic equivalent to that of the programmable filter in the forward path plus the electrical feedback path. Also, the relative speech-noise content in the signals from the hearing aid microphone is sensed and binary words are generated and supplied to the programmable filter for selecting from memory a set of delay line tap coefficients that are effective to impart to the filter the appropriate frequency response for the specific environmental noise condition being detected.
Inventors
- 👤 Harry Levitt
- 👤 Richard S. Dugot
- 👤 Kenneth W. Kopper
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 15:00
CPC Classifications
H; H04; H04R; H04R25/00; H04R25/45; H04R25/453; H03; H03G; H03G5/00; H03G5/16; H04R2225/00; H04R2225/41; H04R2225/43; H04R25/40; H04R25/407; H04R25/50; H04R25/505
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
74 words
A hearing aid comprising at least one input microphone (57), an output receiver (69), and a signal transmission channel interposed between the microphone and the receiver and characterised in that a programmable delay line filter (64) is interposed between the input and output of the transmission channel, the filter being programmed to impart to the hearing aid at least one response characteristic effective to compensate for impaired hearing of the wearer of the aid.
Claim 2
Dependent Claim
74 words
A hearing aid comprising at least one input microphone (57), an output receiver (69), and a signal transmission channel interposed between the microphone and the receiver and characterised in that a programmable delay line filter (64) is interposed between the input and output of the transmission channel, the filter being programmed to impart to the hearing aid at least one response characteristic effective to compensate for impaired hearing of the wearer of the aid.
Claim 3
Dependent Claim
26 words
A hearing aid as defined in claim 1 in which the programmable delay line filter (64) is interposed in a forward path through the transmission channel.
Claim 4
Dependent Claim
26 words
A hearing aid as defined in claim 1 or 2 with programmable signal limiter means (67) interposed between the input and output of the transmission channel.
Claim 5
Dependent Claim
33 words
A hearing aid as defined in claim 3 in which the programmable delay line filter (64) and the programmable signal limiter means (67) are interposed in a feedback path for the transmission channel.
Claim 6
Dependent Claim
31 words
A hearing aid as defined in claim 2, 3 or 4, in which the programmable filter is programmed to effect substantial reduction of acoustic feedback from the receiver to the microphone.
Claim 7
Dependent Claim
70 words
A hearing aid as defined in claim 2 in which the filter comprises a delay line having a multiplicity of taps, first memory means (77) for storing filter-response related coefficients therein, and means jointly responsive to the delay line taps and to coefficients stored in the memory means for providing an output having at least one response characteristic effective to compensate for impaired hearing of the wearer of the aid.
Claim 8
Dependent Claim
31 words
A hearing aid as defined in claim 6 in which the programmable delay line is programmed so as to effect substantial reduction of acoustic feedback from the receiver to the microphone.
Claim 9
Dependent Claim
39 words
A hearing aid as in claim 6 or 7, in which the filter (64) comprises a digital delay line and means (70) for converting analog signals in the said channel to digital signals for application to the delay line.
Claim 10
Dependent Claim
167 words
A hearing aid as described in claim 8 in which the digital delay line (64) comprises second memory means (71) arranged to receive digital signals from the analog-to-digital converting means, register means (72) connected to receive digital signals from the second memory means (71), first digital-to-analog converter means (73) connected to receive digital signals from the register means, timing means controlling the transfer of digital signals from the second memory through the register means to the first digital-to-analog converter means, second digital-to-analog converter means (78) connected to receive filter response related coefficients from the memory means (77) in timed relation to the transfer of digital signals to the first digital-to-analog converter means and to supply analog signals therefrom to the first digital-to-analog converter means for combination therein with digital signals transferred thereto from the second memory means (71), signal summing means (78a) connected to receive the output of the first digital converter means, and sample-and-hold means (79) connected to receive the output of the signal summing means.
Claim 11
Dependent Claim
40 words
A hearing aid as in claim 6 or 7 in which the filter comprises an analog delay line having a multiplicity of taps, and means for periodically sampling analog signals in the channel and supplying them to the delay line.
Claim 12
Dependent Claim
77 words
A hearing aid as described in claim 10 with digital-to-analog converter means (78) connected to receive filter-response related coefficients from the first memory means (77) for conversion to analog values, multiplexer means connected to supply signal samples from the sampling means to the digital converter means for combination with the respective analog values, summing means (78a) for summing the analog values and signal samples, and sample-and-hold means (79) connected to receive the output of the summing means.
Claim 13
Dependent Claim
68 words
A hearing aid comprising at least one input microphone (57), an output receiver (69), and a transmission channel interposed between the microphone and receiver, means controllable to impart different response characteristics to the hearing aid, and means responsive to a characteristic of the signal in the transmission channel for automatically controlling the controllable means to impart a selected one of the different response characteristics to the hearing aid.
Claim 14
Dependent Claim
68 words
A hearing aid comprising at least one input microphone (57), an output receiver (69), and a transmission channel interposed between the microphone and receiver, means controllable to impart different response characteristics to the hearing aid, and means responsive to a characteristic of the signal in the transmission channel for automatically controlling the controllable means to impart a selected one of the different response characteristics to the hearing aid.
Claim 15
Dependent Claim
23 words
A hearing aid as described in claim 12 in which the controlling means is responsive to the signal level in the transmission channel.
Claim 16
Dependent Claim
21 words
A hearing aid as described in claim 12 in which the controlling means is responsive to noise in the transmission channel.
Claim 17
Dependent Claim
36 words
A hearing aid as described in claim 12 in which the controlling means is responsive to the level of speech signals in the transmission channel in excess of the level of noise signals in the channel.
Claim 18
Dependent Claim
114 words
A hearing aid as described in claim 15 in which the controlling means comprises speech detector means (96) for determining when speech signals are in the transmission channel, a plurality of bandpass filter means (97-100) for determining the noise frequency spectrum in the transmission channel, a plurality of comparator means (101-104) each responsive to the speech detector and to respective bandpass filter means for indicating whether the speech level in each bandpass filter exceeds the noise level therein and for actuating the controlling means to impart to the hearing aid a response characteristic effective to compensate for impaired hearing of the wearer of the aid at the noise levels obtaining in the said channel.
Claim 19
Dependent Claim
105 words
A hearing aid as described in claim 16 in which the controlling means also comprises means (109-112) for rectifying a portion of the signals in the transmission channel, a plurality of differently pre-biased comparators (113-116) connected to receive the output of the rectifying means, and means responsive to the outputs of the comparators for generating a signal representative of the average level of the signals in the transmission channel for controlling the controllable means to impart to the hearing aid a response characteristic effective to compensate for impaired hearing of the wearer of the aid at the signal and noise levels obtaining in the channel.
Claim 20
Dependent Claim
60 words
A hearing aid as described in claim 17 in which the controllable means comprises a delay line having a multiplicity of taps, memory means for storing predetermined filter response-related coefficients therein, and means responsive to the controlling means for combining the delay line taps and coefficients to constitute a delay line filter of predetermined response characteristic in the transmission channel.
Claim 21
Independent Claim
102 words
A method of reducing acoustic feedback in a sound system comprising a microphone (57), a transducer (69) and a signal transmission channel interposed between the microphone and transducer, comprising the steps of determining the effect on the amplitude and phase of a signal in the transmission channel as a function of frequency of acoustic feedback between the transducer and microphone, and inserting between the input and output of the transmission channel an electrical feedback path having a filter therein programmed to equalise and reduce the effect of the acoustic feedback both in amplitude and phase on a signal in the transmission channel.
Claim 22
Independent Claim
102 words
A method of reducing acoustic feedback in a sound system comprising a microphone (57), a transducer (69) and a signal transmission channel interposed between the microphone and transducer, comprising the steps of determining the effect on the amplitude and phase of a signal in the transmission channel as a function of frequency of acoustic feedback between the transducer and microphone, and inserting between the input and output of the transmission channel an electrical feedback path having a filter therein programmed to equalise and reduce the effect of the acoustic feedback both in amplitude and phase on a signal in the transmission channel.
Claim 23
Independent Claim
108 words
A method of reducing acoustic feedback in a hearing aid comprising a microphone (57), a receiver (69) fitted in an ear of a wearer of the aid, and a signal transmission channel interposed between the microphone and transducer, comprising the steps of determining the effect on the amplitude and phase of a signal in the transmission channel as a function of frequency of acoustic feedback between the receiver and microphone, and inserting between the input and output of the transmission channel a programmable filter (64) programmed to equalise and reduce the effect of the acoustic feedback both in amplitude and phase on a signal in the transmission channel.
Claim 24
Independent Claim
108 words
A method of reducing acoustic feedback in a hearing aid comprising a microphone (57), a receiver (69) fitted in an ear of a wearer of the aid, and a signal transmission channel interposed between the microphone and transducer, comprising the steps of determining the effect on the amplitude and phase of a signal in the transmission channel as a function of frequency of acoustic feedback between the receiver and microphone, and inserting between the input and output of the transmission channel a programmable filter (64) programmed to equalise and reduce the effect of the acoustic feedback both in amplitude and phase on a signal in the transmission channel.
Claim 25
Dependent Claim
29 words
A method of reducing feedback in a hearing aid as described in claim 20 in which the programmable filter is inserted in a forward path through the transmission channel.
Claim 26
Dependent Claim
30 words
A method of reducing feedback in a hearing aid as described in claim 20 in which the programmable filter is inserted in an electrical feedback loop for the transmission channel.
Claim 27
Dependent Claim
110 words
A hearing aid comprising at least two input microphone channels, means for adjusting the amplitude and phase characteristics of each of the microphone channels, means for summing the outputs of the microphone channels, an output receiver, a signal transmission channel connected to receive the output of the summing means and to provide an output to the receiver, and a programmable filter interposed between the summing means and the output of the transmission channel, the filter being programmed to impart to the hearing aid at least one response characteristic effective to compensate for impaired hearing of the wearer of the aid and to reduce the effects of both noise and reverberation.
Claim 28
Dependent Claim
110 words
A hearing aid comprising at least two input microphone channels, means for adjusting the amplitude and phase characteristics of each of the microphone channels, means for summing the outputs of the microphone channels, an output receiver, a signal transmission channel connected to receive the output of the summing means and to provide an output to the receiver, and a programmable filter interposed between the summing means and the output of the transmission channel, the filter being programmed to impart to the hearing aid at least one response characteristic effective to compensate for impaired hearing of the wearer of the aid and to reduce the effects of both noise and reverberation.
References Cited (Backward Citations)
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