Systems and methods for wireless transmission of biopotentials
First Claim
1. An apparatus comprising:
- a completely passive electronic circuit having a varactor diode coupled to two electrodes configured to provide an inductance and a variable capacitance, wherein;
the electronic circuit is configured to receive an excitation signal and a biosignal, wherein the excitation signal has a frequency between 30 MHz and 10 GHz;
the electronic circuit has backscatter properties that vary in response to the biosignal, wherein the biosignal is generated by a biopotential that is detected by the two electrodes;
the electronic circuit is configured to transmit a backscatter signal when the electronic circuit receives the excitation signal and the biosignal; and
a characteristic of the biosignal can be determined by demodulating the backscatter signal.
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Abstract
The invention relates to wireless biotelemetry of low level bioelectric and biosensor signals by directly modulating the backscatter of a resonant circuit. Low level electrical analog or digital signals are directly applied to a resonant circuit containing a voltage-variable capacitor such as a varactor diode, that proportionally shifts the resonant frequency and so amplitude of radiofrequency backscatter in a way that represents analog bioelectric or biosensor waveform data. By strongly driving the resonant circuit with a radiofrequency source, a voltage variable capacitance can be caused to amplify the bio-signal level by a parametric process and so provide sufficient sensitivity to telemeter for low millivolt and microvolt level signals without additional amplification. A feature of the device is its simplicity and that it accomplishes both modulation and preamplification of low level sensor signals by the same variable capacitance circuit which reduces the device size and power consumption.
78 Citations
24 Claims
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1. An apparatus comprising:
a completely passive electronic circuit having a varactor diode coupled to two electrodes configured to provide an inductance and a variable capacitance, wherein; the electronic circuit is configured to receive an excitation signal and a biosignal, wherein the excitation signal has a frequency between 30 MHz and 10 GHz; the electronic circuit has backscatter properties that vary in response to the biosignal, wherein the biosignal is generated by a biopotential that is detected by the two electrodes; the electronic circuit is configured to transmit a backscatter signal when the electronic circuit receives the excitation signal and the biosignal; and a characteristic of the biosignal can be determined by demodulating the backscatter signal. - 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)
Specification