Wavelength division sensing RF vibrometer for accurate measurement of complex vibrations
First Claim
1. A method for non-contact measurement of mechanical vibration, comprising:
- transmitting a radio frequency (RF) signal at a first carrier frequency toward a target;
receiving a reflected RF signal from the target;
down-converting the reflected RF signal to a baseband signal;
determining a number N from the baseband signal, wherein N is a number of frequency components of vibration of the target;
determining N pairs of harmonics;
determining N amplitude ratios at a second carrier frequency, where each of the N amplitude ratios is an amplitude ratio of a corresponding pair of harmonics of the N pairs of harmonics at the second carrier frequency, the second carrier frequency different than the first carrier frequency; and
determining information regarding the vibration of the target from the N amplitude ratios.
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Accused Products
Abstract
Embodiments of the present invention provide a method for non-contact detection techniques of mechanical vibrations utilizing a radio frequency system incorporating multiple carrier wavelengths. The new detection method measures multiple harmonic pairs at a carrier frequency and improves the detection accuracy and reliability by first inspecting the Bessel function coefficient of each harmonic and then determining the harmonic amplitude. The original mechanical vibration can then be reconstructed. Embodiments can be used to realize sensing of complex non-sinusoidal vibrations using a wavelength division sensing technique and allow non-contact detection through walls, smoke, fog or other low visibility environments with the advantage of longer range detection and easy integration at a low cost.
16 Citations
28 Claims
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1. A method for non-contact measurement of mechanical vibration, comprising:
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transmitting a radio frequency (RF) signal at a first carrier frequency toward a target; receiving a reflected RF signal from the target; down-converting the reflected RF signal to a baseband signal; determining a number N from the baseband signal, wherein N is a number of frequency components of vibration of the target; determining N pairs of harmonics; determining N amplitude ratios at a second carrier frequency, where each of the N amplitude ratios is an amplitude ratio of a corresponding pair of harmonics of the N pairs of harmonics at the second carrier frequency, the second carrier frequency different than the first carrier frequency; and determining information regarding the vibration of the target from the N amplitude ratios. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for non-contact measurement of mechanical vibration, comprising:
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a transmitter, wherein the transmitter transmits a radio frequency (RF) signal at a first carrier frequency toward a target; a receiver, wherein the receiver receives a reflected RF signal from the target; a down-converter, wherein the down-converter down-converts the reflected RF signal to a baseband signal; and a processor adapted to determine; a number N from the baseband signal, wherein N is a number of frequency components of vibration of the target; N pairs of harmonics; N amplitude ratios at a second carrier frequency, where each of the N amplitude ratios is an amplitude ratio of a corresponding pair of harmonics of the N pairs of harmonics at the second carrier frequency, the second carrier frequency different than the first carrier frequency; and information regarding the vibration of the target from the N amplitude ratios. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method for non-contact measurement of mechanical vibration, comprising:
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transmitting a radio frequency (RF) signal at a first carrier frequency toward a target; receiving a reflected RF signal from the target as a received RF signal; down-converting the received RF signal to a baseband signal; determining a number N from the baseband signal, wherein N is a number of frequency components of vibration of the target; determining N amplitude ratios of a pair of harmonics, wherein each harmonic of the pair of harmonics corresponds to one of the N frequency components, wherein the N amplitude ratios are determined at a corresponding N carrier frequencies; and determining information regarding the vibration of the target from the N amplitude ratios of the pair of harmonics. - View Dependent Claims (18, 19, 20, 21, 22)
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23. An apparatus for non-contact measurement of mechanical vibration, comprising:
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a transmitter, wherein the transmitter transmits a radio frequency (RF) signal at a first carrier frequency toward a target; a receiver, wherein the receiver receives a reflected RF signal from the target as a received RF signal; a down-converter, wherein the down-converter down-converts the received RF signal to a baseband signal; a processor adapted to determine the following; a number N from the baseband signal, wherein N is a number of frequency components of vibration of the target; N amplitude ratios of a pair of harmonics, wherein each harmonic of the pair of harmonics corresponds to one of the N frequency components, wherein the N amplitude ratios are determined at a corresponding N carrier frequencies; and information regarding the vibration of the target from the N amplitude ratios of the pair of harmonics. - View Dependent Claims (24, 25, 26, 27, 28)
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Specification