Optoelectronic Oscillator RF Sensor for Acoustic Signal Detection
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Solution Overview
Problem
Existing photonic RF sensor systems face challenges in reliability and noise levels for remote detection of acoustical signals, and they often fail to provide spectrum information effectively.
Innovation Solution
A photonic RF sensor system using an optoelectronic oscillator with a light generator, modulator, optical fiber, and RF coupler to transmit and receive modulated carrier signals, featuring a circuit for removing the carrier frequency and processing sideband signals to detect and classify acoustical and vibrational signals, employing a phase shifter, mixer, and signal processor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fiber-based acoustic sensor techniques are deployed close to the area of interest, then acoustic sensing capability is achieved, but the system cannot provide spectrum information and has limited detection range
Solution Approach 1:
The system segments the acoustic signal processing into multiple frequency components through Fourier transformation, allowing simultaneous analysis of different spectral components while maintaining the ability to detect acoustic events remotely
Solution Approach 2:
An optical intermediary (light wave) is introduced to transmit acoustic signal information over long distances without electromagnetic interference, enabling both remote detection and preservation of spectrum information through optical frequency domain analysis
2Length of moving object
If traditional RF sensor systems are used for remote detection, then detection range is extended, but reliability and noise performance deteriorate
Solution Approach 1:
The system replaces traditional electrical RF transmission with optical transmission using light waves, eliminating electromagnetic interference and improving reliability while maintaining extended detection range through the immunity of optical fibers to environmental electromagnetic noise
3Power
If carrier frequency is retained in the received signal, then signal strength is maintained, but noise and interference increase
Solution Approach 1:
The carrier frequency component is extracted and removed from the received optical signal, leaving only the acoustic sideband information. This extraction process eliminates the harmful carrier-related noise and interference while preserving the useful acoustic signal components
Data Source
AI summary
A method and system comprising:an optoelectronic oscillator comprising a light generator, a modulator, and at least one optical fiber, the optoelectronic oscillator operating to send a modulated carrier signal through the optical fiber into a target area and receive the return signal;a circuit for removal of the carrier frequency operatively connected to the oscillator comprising at least one phase shifter; at least one mixer operatively connected to the at least one phase shifter; at least control circuit operatively connected the at least one mixer and the at least one phase shifter for controlling the phase shifter and operating to cancel signals other than the sideband signals;a signal processor for processing the sideband signals to detect acoustical and/or vibrational signals from the target area. The method comprises sensing vibrational and/or acoustical signals for detection of acoustical and/or vibrational signals in the target area.