Transponders
First Claim
Patent Images
1. Information-transmission apparatus comprising:
- a transmitter for transmitting signals at a first frequency, and transponder apparatus including;
a non-linear device having a non-linear impedance,a receive resonant circuit connected to the non-linear device for obtaining power from transmissions from the transmitter to vary the non-linear impedance of the said device and generate a non-sinusoidal waveform across the device when transmissions are received, the receive resonant circuit being at least broadly tuned to a frequency range in which the first frequency occurs,a transmit resonant circuit, resonant at a second frequency, connected to the non-linear device, andtransducer means for varying the resonant frequency of the transmit resonant circuit;
a receiver having a receiving circuit at least broadly tuned to a frequency range in which the second frequency occurs; and
a frequency indicating circuit, coupled to the receiving circuit, for providing a signal indicative of the frequency of a signal received by the receiving circuit.
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Abstract
A passive transponder, particularly for dental or medical applications, is described in which signals received by one or more receive resonant circuits are changed in frequency either up or down by a non-linear device coupled to one or more transmit resonant circuits. Each transmit resonant circuit includes a transducer whose impedance depends on a quantity whose value is to be transmitted and thus the frequency of signals received from the transponder depends on the value of the quantity.
157 Citations
33 Claims
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1. Information-transmission apparatus comprising:
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a transmitter for transmitting signals at a first frequency, and transponder apparatus including; a non-linear device having a non-linear impedance, a receive resonant circuit connected to the non-linear device for obtaining power from transmissions from the transmitter to vary the non-linear impedance of the said device and generate a non-sinusoidal waveform across the device when transmissions are received, the receive resonant circuit being at least broadly tuned to a frequency range in which the first frequency occurs, a transmit resonant circuit, resonant at a second frequency, connected to the non-linear device, and transducer means for varying the resonant frequency of the transmit resonant circuit; a receiver having a receiving circuit at least broadly tuned to a frequency range in which the second frequency occurs; and a frequency indicating circuit, coupled to the receiving circuit, for providing a signal indicative of the frequency of a signal received by the receiving circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 28, 29, 30, 31, 32)
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25. Transponder apparatus including:
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a non-linear device having a non-linear impedance; a receive resonant circuit, connected to the non-linear device, for obtaining power from transmissions by a transmitter to vary the non-linear impedance of the said device and generate a non-sinusoidal waveform across the device when transmissions are received, the receive resonant circuit being at least broadly tuned to a first frequency; a transmit resonant circuit, resonant at a second frequency, connected to the non-linear device to apply the non-sinusoidal waveform to the transmit resonant circuit to cause oscillations to occur therein; and transducer means for varying the resonant frequency of the transmit resonant circuit.
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33. Information-transmission apparatus comprising:
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A. a transmitter for transmitting signals at a first frequency, and transponder apparatus including; a non-linear device having a non-linear impedance, a receive resonant circuit connected to the non-linear device for obtaining power from transmissions from the transmitter to vary the non-linear impedance of the said device and generate a non-sinusodial waveform having a plurality of harmonic frequencies across the device when transmissions are received, the receive resonant circuit being at least broadly tuned to a frequency range in which the first frequency occurs, a transmit resonant circuit, resonant at a second frequency, connected to the non-linear device for oscillation in response to a harmonic of said non-sinusoidal waveform having the resonant frequency of said transmit resonant circuit, and transducer means for varying the resonant frequency of the transmit resonant circuit; B. a receiver having a receiving circuit at least broadly tuned to a frequency range in which the second frequency occurs; and C. a frequency indicating circuit, coupled to the receiving circuit, for providing a signal indicative of the frequency of a signal received by the receiving circuit.
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Specification