Short range inductively coupled communication system employing time variant modulation
First Claim
1. A short range communication system for transmitting an audio frequency input signal comprising:
- transmission means for receiving said audio frequency input signal and for providing a pulse sequence time variant modulated by said audio frequency input signal,transmission means including a transmission magnetic element for transmitting said pulse sequence; and
receiver means, including a receiving magnetic element magnetically coupled to said transmission loop, for receiving said pulse sequence and for demodulating said pulse sequence to reproduce said audio frequency input signal;
wherein said receiver means is freely movable relative to said transmission means.
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Accused Products
Abstract
A short range magnetically coupled wireless communication system employs time variant modulation of a high repetition rate pulse stream and magnetic coupling between a transmission magnetic element and a receiving magnetic element. The pulse stream is modulated by an input audio frequency signal in the time domain, for example, through pulse position modulation, pulse width modulation or pulse symmetry modulation. The receiving magnetic element is coupled to a demodulator circuit which detects the transmitted pulses induced in the receiving magnetic element and reproduces the audio frequency signal. Transmission over short range is thus efficiently accomplished through magnetic coupling in a simple, low cost, low power consumption communication system.
119 Citations
40 Claims
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1. A short range communication system for transmitting an audio frequency input signal comprising:
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transmission means for receiving said audio frequency input signal and for providing a pulse sequence time variant modulated by said audio frequency input signal, transmission means including a transmission magnetic element for transmitting said pulse sequence; and receiver means, including a receiving magnetic element magnetically coupled to said transmission loop, for receiving said pulse sequence and for demodulating said pulse sequence to reproduce said audio frequency input signal; wherein said receiver means is freely movable relative to said transmission means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 35, 36, 37, 40)
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15. A short range wireless transmission system for transmitting an input signal, comprising:
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means for providing a waveform having substantially linear characteristics over at least half a period thereof; means for receiving said waveform and for receiving said input signal and providing a time variant modulated output pulse stream; a magnetic transmission element; and means for receiving said time variant modulated pulse stream and for driving said magnetic transmission magnetic element with said pulse stream. - View Dependent Claims (16, 17, 18, 19, 20, 38)
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21. A receiver adapted to receive a pulse train time variant modulated by an audio frequency input signal, transmitted from a transmitter inductively coupled to said receiver, comprising:
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a receiver magnetic element for receiving signals induced therein; means for detecting pulses of the transmitted pulse train in said received signals; and means for receiving said detected pulses and demodulating the pulse train to reproduce the audio frequency input signal. - View Dependent Claims (22, 23, 25, 26)
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24. A receiver adapted to receive a pulse train time variant modulated by an input signal, transmitted from a transmitter inductively coupled to said receiver, comprising:
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a receiver magnetic element for receiving signals induced therein; means for detecting pulses of the transmitted pulse train in said received signals; means for receiving said detected pulses and demodulating the pulse train to reproduce the input signal; a speaker; and audio driver means, coupled to said means for demodulating and said speaker, for driving said speaker with said demodulated input signal to reproduce said input signal as an audible audio signal.
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27. A short range wireless communication system, comprising:
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a transmitter unit, including; an magnetic transmission element; an input for receiving an input signal; means for providing a pulse train time variant modulated by said input signal; and means for driving said transmission magnetic element with said modulated pulse train; and a portable receiver unit, adapted to be worn by a user, including; a receiving magnetic element for inductively receiving said pulse train therein; and means for providing a reproduced input signal which is substantially independent of variations in distance between said transmitter unit and said receiver unit within a predetermined range, including; a pulse detector, coupled to said receiving magnetic element, for discriminating the pulses in said pulse train from noise; and a demodulator circuit, coupled to said pulse detector, for receiving said detected pulse train and demodulating said pulse train to reproduce said input signal. - View Dependent Claims (28, 29)
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30. A method for transmitting an input signal between a transmitter having a transmitting magnetic element and a receiver having a receiving magnetic element, comprising the steps of:
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receiving an audio frequency input signal; time variant modulation of a pulse train with said audio frequency input signal so as to provide a pulse train modulated in the time domain; providing the modulated pulse train to said transmitting magnetic element; receiving the modulated pulse train in said receiving magnetic element, said receiving magnetic element being positioned at a variable distance from said transmitting magnetic element through magnetic coupling of said transmitting magnetic dement and said receiving magnetic element; demodulating said received modulated pulse train to reproduce said audio frequency input signal in said receiver; and converting said reproduced audio frequency input signal to an audible acoustic signal.
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31. A wireless transmission circuit for transmitting an audio frequency input signal, comprising:
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a monolithic integrated circuit chip having electrical circuits formed thereon, including; means for receiving the audio frequency input signal; time variant modulation means for providing a pulse train modulated in the time domain by said audio frequency input signal; output means for providing said time domain modulated pulse train to circuit components external to said monolithic integrated circuit chip; and means for receiving a power supply voltage; and magnetic element means, coupled to said output means of said monolithic integrated circuit chip, for receiving said time domain modulated pulse train as a drive signal thereto and directly transmitting said pulse train Without employing a carrier. - View Dependent Claims (32, 33, 39)
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34. A receiver for receiving a high repetition rate time variant modulated pulse train and demodulating it to provide an audio frequency signal, comprising:
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a receiving magnetic element for inductively receiving the high repetition rate pulse train therein; and a monolithic integrated circuit chip having electrical circuits formed thereon, including; means for receiving the signal induced in the receiving magnetic element; means for detecting pulses in the signal induced in the receiving magnetic element; means for demodulating the induced signal; means for outputting the demodulated pulse train to an audio output device external to said monolithic integrated circuit chip; means for receiving a power supply voltage from a source external to said monolithic integrated circuit chip; and means for coupling the monolithic integrated circuit chip to a reference voltage.
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Specification