Digital hearing aid using differential signal representations
First Claim
1. A hearing compensation system comprising:
- an input transducer for converting acoustical information at an input thereof to electrical signals at an output thereof;
a differential analog-to-digital converter sampling said electrical signals output from said input transducer at an input thereof and outputting differential signal samples at an output thereof as digital signals, said differential signal samples representing the difference between successive samples of said electrical signals;
a digital signal processing circuit having an input connected to said output of said differential analog-to-digital converter and operating on said differential signal samples to form processed differential signal samples at an output thereof;
an integrator having an input connected to said output of said digital signal processing circuit to form a sum of successive ones from said processed differential signal samples at an output thereof;
a digital-to-analog converter having an input connected to said output of said integrator to form an analog signal from said sum of said successive ones of said processed differential signal samples at an output thereof; and
an output transducer having an input connected to said output of said digital-to-analog converter to convert said analog signal from said digital-to-analog converter to acoustical information at an output thereof.
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Accused Products
Abstract
A hearing compensation system comprises an input transducer for converting acoustical information at an input thereof to electrical signals at an output thereof, a differential analog-to-digital converter sampling the electrical signals output from the input transducer at an input thereof and outputting differential signal samples at an output thereof, a digital signal processing circuit having an input connected to the output of the differential analog-to-digital converter and operating on the differential signal samples to form processed differential signal samples at an output thereof, and an output transducer for converting electrical signals at an input thereof to acoustical information at an output thereof, the processed differential signal samples coupled to the input of the output transducer.
135 Citations
27 Claims
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1. A hearing compensation system comprising:
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an input transducer for converting acoustical information at an input thereof to electrical signals at an output thereof; a differential analog-to-digital converter sampling said electrical signals output from said input transducer at an input thereof and outputting differential signal samples at an output thereof as digital signals, said differential signal samples representing the difference between successive samples of said electrical signals; a digital signal processing circuit having an input connected to said output of said differential analog-to-digital converter and operating on said differential signal samples to form processed differential signal samples at an output thereof; an integrator having an input connected to said output of said digital signal processing circuit to form a sum of successive ones from said processed differential signal samples at an output thereof; a digital-to-analog converter having an input connected to said output of said integrator to form an analog signal from said sum of said successive ones of said processed differential signal samples at an output thereof; and an output transducer having an input connected to said output of said digital-to-analog converter to convert said analog signal from said digital-to-analog converter to acoustical information at an output thereof.
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2. A hearing compensation system comprising:
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an input transducer for converting acoustical information at an input thereof to electrical signals at an output thereof; a differential analog-to-digital converter sampling said electrical signals output from said input transducer at an input thereof and outputting differential signal samples at an output thereof as digital signals, said differential signal samples representing the difference between successive samples of said electrical signals; a plurality of bandpass filters, each bandpass filter having an input connected to said output of said differential analog-to-digital converter to separate said differential signal samples according to frequency; a plurality of digital signal processing circuits, each individual digital signal processing circuit having an input connected to a different one of said plurality of bandpass filters and an output summed with said outputs of all other ones of said digital signal processing circuits to form processed differential signal samples; an integrator having an input connected to said processed differential signal samples from said plurality of digital signal processing circuits to form a sum of successive ones of said processed differential signal samples at an output thereof; a digital-to-analog converter having an input connected to said output of said integrator to form an analog signal from said sum of said successive ones of said processed differential signal samples at an output thereof; and an output transducer having an input connected to said output of said digital-to-analog converter to convert said analog signal from said digital-to-analog converter to acoustical information at an output thereof.
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3. A hearing compensation system comprising:
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an input transducer for converting acoustical information at an input thereof to electrical signals at an output thereof; a differential analog-to-digital converter sampling said electrical signals output from said input transducer at an input thereof and outputting differential signal samples at an output thereof as digital signals, said differential signal samples representing the difference between successive samples of said electrical signals; a first plurality of bandpass filters, said first plurality of bandpass filters for filtering electrical signals below a crossover frequency, each bandpass filter having an input connected to said output of said differential analog-to-digital converter to separate said differential signal samples according to frequency; a second plurality of bandpass filters, said second plurality of bandpass filters for filtering electrical signals above said crossover frequency, each bandpass filter having an input connected to said output of said differential analog-to-digital converter to separate said differential signal samples according to frequency; a first plurality of digital signal processing circuits, each individual digital signal processing circuit in said first plurality of digital signal processing circuits having an input connected to a different one of said first plurality of bandpass filters and an output summed with said outputs of all other ones of said first plurality of digital signal processing circuits to form first processed differential signal samples; a second plurality of digital signal processing circuits, each individual digital signal processing circuit in said second plurality of digital signal processing circuits having an input connected to a different one of said second plurality of bandpass filters and an output summed with said outputs of all other ones of said second plurality of digital signal processing circuits to form second processed differential signal samples; a first integrator having an input connected to said first processed differential signal samples from said first plurality of digital signal processing circuits to form a first sum of successive ones of said processed differential signal samples at an output thereof; a second integrator having an input connected to said second processed differential signal samples from said second plurality of digital signal processing circuits to form a second sum of successive ones of said processed differential signal samples at an output thereof; a first digital-to-analog converter having an input connected to said output of said first integrator to form a first analog signal from said first sum of said successive ones of said first processed differential signal samples at an output thereof; a second digital-to-analog converter having an input connected to said output of said second integrator to form a second analog signal from said second sum of said successive ones of said second processed differential signal samples at an output thereof; a first output transducer for converting electrical signals below said crossover frequency having an input connected to said output of said first digital-to-analog converter to convert said first analog signal from said first digital-to-analog converter to acoustical information at an output thereof; and a second output transducer for converting electrical signals above said crossover frequency having an input connected to said output of said second digital-to-analog converter to convert said second analog signal from second first digital-to-analog converter to acoustical information at an output thereof. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11)
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12. A hearing compensation system comprising:
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an input transducer for converting acoustical information at an input thereof to electrical signals at an output thereof; a differential analog-to-digital converter sampling said electrical signals output from said input transducer at an input thereof and outputting differential signal samples at an output thereof as digital signals, said differential signal samples representing the difference between successive samples of said electrical signals; a digital signal processing circuit having an input connected to said output of said differential analog-to-digital converter and operating on said differential signal samples to form processed differential signal samples at an output thereof; a pulse coder having an input connected to said processed differential signal samples of said digital signal processing circuit to form an output pulse for each of said processed differential signal samples, said output pulse having a duration proportional to the magnitude of each of said processed differential signal samples at an output thereof; a driver amplifier having an input connected to said output of said pulse coder to form a driving voltage having a duration proportional to said duration of said output pulse from said pulse coder at an output thereof; and an output transducer having an input connected to said output of said driver amplifier to convert said driving voltage from said driver amplifier to acoustical information at an output thereof. - View Dependent Claims (13)
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14. A hearing compensation system comprising:
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an input transducer for converting acoustical information at an input thereof to electrical signals at an output thereof; a differential analog-to-digital converter sampling said electrical signals output from said input transducer at an input thereof and outputting differential signal samples at an output thereof as digital signals, said differential signal samples representing the difference between successive samples of said electrical signals; a plurality of bandpass filters, each bandpass filter having an input connected to said output of said differential analog-to-digital converter to separate said differential signal samples according to frequency into a plurality of filtered differential signal samples; a plurality of digital signal processing circuits, each individual digital signal processing circuit having an input connected to a different one of said plurality of bandpass filters and an output summed with said outputs of all other ones of said digital signal processing circuits, wherein each individual digital signal processing circuit operates on one of said filtered differential signal samples to form processed differential signal samples; a pulse coder having an input connected to said processed differential signal samples of said plurality of digital signal processing circuits to form an output pulse for each of said processed differential signal samples, said output pulse having a duration proportional to the magnitude of each of said processed differential signal samples at an output thereof; a driver amplifier having an input connected to said output of said pulse coder to form a driving voltage having a duration proportional to said duration of said output pulse from said pulse coder at an output thereof; and an output transducer having an input connected to said output of said driver amplifier to convert said output of said driver amplifier to acoustical information at an output thereof. - View Dependent Claims (15)
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16. A hearing compensation system comprising:
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an input transducer for converting acoustical information at an input thereof to electrical signals at an output thereof; a differential analog-to-digital converter sampling said electrical signals output from said input transducer at an input thereof and outputting differential signal samples at an output thereof as digital signals, said differential signal samples representing the difference between successive samples of said electrical signals; a first plurality of bandpass filters, said first plurality of bandpass filters for filtering electrical signals below a crossover frequency, each bandpass filter having an input connected to said output of said differential analog-to-digital converter to separate said differential signal samples according to frequency; a second plurality of bandpass filters, said second plurality of bandpass filters for filtering electrical signals above said crossover frequency, each bandpass filter having an input connected to said output of said differential analog-to-digital converter to separate said differential signal samples according to frequency; a first plurality of digital signal processing circuits, each individual digital signal processing circuit in said first plurality of digital signal processing circuits having an input connected to a different one of said first plurality of bandpass filters and an output summed with said outputs of all other ones of said first plurality of digital signal processing circuits to form first processed differential signal samples; a second plurality of digital signal processing circuits, each individual digital signal processing circuit in said second plurality of digital signal processing circuits having an input connected to a different one of said second plurality of bandpass filters and an output summed with said outputs of all other ones of said second plurality of digital signal processing circuits to form second processed differential signal samples; a first pulse coder having an input connected to said first processed differential signal samples from said first plurality of digital signal processing circuits to form a first output pulse for each of said first processed differential signal samples, said first output pulse having a duration proportional to the magnitude of said first processed differential signal samples at an output thereof; a second pulse coder having an input connected to said second processed differential signal samples from said second plurality of digital signal processing circuits to form a second output pulse for each of said second processed differential signal samples, said second output pulse having a duration proportional to the magnitude of said second processed differential signal samples at an output thereof; a first driver amplifier having an input connected to said output of said first pulse coder to form a first driving voltage having a duration proportional to said duration of said first output pulse from said first pulse coder at an output thereof; a second driver amplifier having an input connected to said output of said second pulse coder to form a second driving voltage having a duration proportional to said duration of said second output pulse from said second pulse coder at an output thereof; a first output transducer for converting electrical signals below said crossover frequency having an input connected to said output of said first driver amplifier to convert said first driving voltage from said first driver amplifier to acoustical information at an output thereof; and a second output transducer for converting electrical signals above said crossover frequency having an input connected to said output of said second driver amplifier to convert said second driving voltage from said second driver amplifier to acoustical information at an output thereof. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A differential signal output driver, comprising:
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a pulse coder having an input connected to a differential signal sample to form an output pulse for said differential signal sample, said output pulse having a duration proportional to the magnitude of said differential signal sample at an output thereof; a driver amplifier having an input connected to said output of said pulse coder to form a driving voltage having a duration proportional to said duration of said output pulse from said pulse coder at an output thereof; and an output transducer having an input connected to said output of said driver amplifier to convert said output of said driver amplifier to acoustical information at an output thereof. - View Dependent Claims (27)
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Specification