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US 2017/0360317 A1Published application
Wireless Vibrometer with Antenna Array
AssigneeWisconsin Alumni Research Foundation
InventorsXinyu Zhang, Teng Wei, Shu Wang, Anfu Zhou
Life of this patent
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Abstract
A wireless vibrometer employs an antenna array to significantly boost the signal-to-noise ratio of faint received signals twin small objects vibrating at acoustic frequencies. This technique may be used to provide an improved physiological monitor (such as a pulse detector) or for long-range eavesdropping using the emitted power from a cell phone or the like.
Claims16
A wireless vibrometer comprising:
- an antenna array having antennas distributed over at least one dimension;
- a transmitter connectable to given antennas of the array, the transmitter shifting at least one of a relative phase and amplitude of a transmitter radiofrequency signal transmitted from each given antenna according to a transmission weight associated with each given antenna;
- a receiver connectable to given antennas of the array, the receiver shifting at least one of a relative phase and amplitude of a reflection of the radiofrequency signal received from each given antenna according to a reception weight associated with each given antenna before combining the reflection radiofrequency signals to a received signal;
- and
- an electronic computer executing a program stored in a non-transitive medium to:
- (a) extract an audio signal from the received signal;
- (b) evaluate the audio signal to adjust the transmission weights and reception weights to provide a processed audio signal improved signal-to-noise ratio;
- and
- (c) output a measure of the processed audio signal.
6 more elements
A system for communicating, audio data comprising:
- a wireless transmitter providing a speaker for outputting an audio signal and a transmitter for transmitting an encrypted radio signal;
- a wireless vibrometer including:
- an antenna array having antennas distributed over at least one dimension;
- a receiver connectable to given antennas of the array, the receiver receiving the encrypted radio signal at each given antenna and shifting at least one of a relative phase and amplitude of the received radiofrequency signal according to a reception weight associated with each given antenna before combining the received radiofrequency signals to a received signal;
- and
- an electronic computer executing a program stored in a non-transitive medium to:
- (a) measure variations in electrical power of the encrypted radio signal over time;
- (b) extract the audio signal from the variations in electrical power;
- (c) employ the audio signal to adjust the reception weights to provide a processed audio signal improved signal-to-noise ratio;
- and
- (c) output the audio signal.
8 more elements
A wireless transmitter hardened against eavesdropping comprising:
- a speaker for outputting an audio signal;
- a transmitter for receiving data and a power control signal and transmitting the data in encrypted form at a power determined by the power control signal;
- and
- an audio noise source providing an audio noise signal in a bandwidth of a human voice and communicating with the transmitter to provide at least a portion of the power control signal to the transmitter;
- wherein the audio noise, source provides a variation in transmitting power comparable to that produced without the audio noise source as a result of vibration of portions of the wireless transmitter under an influence of the audio signal.
2 more elements
Dependencies are inferred from the claim text.