Infrared audio transmitter system
First Claim
1. An assistive listening system for transmitting audio sound waves over an infrared signal, said system comprising:
- means for converting said audio sound waves to an audio electrical signal, said audio electrical signal including upper and lower frequency signals;
oscillator means for generating a base carrier electrical signal;
means for modulating said base carrier electrical signal with said audio electrical signal so as to generate a modulated electrical signal, said modulated electrical signal having an associated duty cycle;
emitter means for converting said modulated electrical signal into a corresponding infrared light signal, said emitter means having an associated power dissipation varying with the duty cycle of said modulated electrical signal; and
means for adjusting the duty cycle of said modulated electrical signal so as to adjust the current through said emitter means and thereby limit the power dissipation of said emitter means.
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Accused Products
Abstract
An infrared assistive listening system capable of enhanced performance in medium-sized locations, such as courtrooms, classrooms, and conference rooms, is realized by a system comprising a pressure zone microphone capable of picking up distant speakers, a high-gain pre-amplifier, an equalization and pre-emphasis circuit, an automatic gain control and limiting circuit, a mute feature capable of remote activation, a FM modulator, a pulse width modulator, and a high-power single front throw infrared emitter. Another embodiment of the invention employs an multi-directional infrared emitter array in conjunction with the single front throw emitter.
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Citations
40 Claims
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1. An assistive listening system for transmitting audio sound waves over an infrared signal, said system comprising:
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means for converting said audio sound waves to an audio electrical signal, said audio electrical signal including upper and lower frequency signals; oscillator means for generating a base carrier electrical signal; means for modulating said base carrier electrical signal with said audio electrical signal so as to generate a modulated electrical signal, said modulated electrical signal having an associated duty cycle; emitter means for converting said modulated electrical signal into a corresponding infrared light signal, said emitter means having an associated power dissipation varying with the duty cycle of said modulated electrical signal; and means for adjusting the duty cycle of said modulated electrical signal so as to adjust the current through said emitter means and thereby limit the power dissipation of said emitter means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An assistive listening system for transmitting audio sound waves over an infrared signal, said system comprising:
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means for converting said audio sound waves to an audio electrical signal, said audio electrical signal including upper and lower frequency signals; oscillator means for generating a base carrier electrical signal; means for modulating said base carrier electrical signal with said audio electrical signal so as to generate a modulated electrical signal, said modulated electrical signal having an associated duty cycle; and emitter means for converting said modulated electrical signal into a corresponding infrared light signal, said emitter means having an associated power dissipation varying with the duty cycle of said modulated electrical signal, and said emitter means including a single front throw emitter for transmitting said infrared light signal substantially along a single direction, and a multi-directional emitter array for transmitting said infrared light signal at least along the rear and sides of said single direction. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. An assistive listening system for transmitting audio sound waves over an infrared signal, said system comprising:
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means for converting said audio sound waves to an audio electrical signal, said audio electrical signal including upper and lower frequency signals; oscillator means for generating a base carrier electrical signal; means for modulating said base carrier electrical signal with said audio electrical signal so as to generate a modulated electrical signal, said modulated electrical signal having an associated duty cycle; emitter means for converting said modulated electrical signal into a corresponding infrared light signal, said emitter means having an associated power dissipation varying with the duty cycle of said modulated electrical signal; mute means responsive to a control signal for selectively disabling said means for modulating while allowing the transmission of said base carrier electrical signal so as to cease audio transmission; and remote control means for generating said control signal. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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Specification