4results about How to "Accurate demodulation" patented technology

The present specification relates to the technical field of fiber-optic gyroscopes, and discloses a reciprocal structure 3x3 fiber-optic gyroscope and a use method thereof, to solve the problems of poor anti-interference, complex calculation, and no consideration of the influence of temperature change on test results, poor environmental adaptability, and limited practicality of a typical non-reciprocal structure 3x3 fiber-optic gyroscope; three photoelectric detectors, a 2x2 coupler, a 3x3 coupler, a temperature sensor, and a signal processing module; the 2x2 coupler, the 3x3 coupler, the first photoelectric detector D1, the second photoelectric detector D2, and the third photoelectric detector D3 constitute a reciprocal structure 3x3 fiber-optic gyroscope optical path. The reciprocal structure 3x3 fiber-optic gyroscope extracts a reciprocal end output signal, uses the reciprocal end output signal as a reference quantity for differential demodulation, eliminates the influence of optical path loss variation and light source fluctuation on the gyroscope output signal, and greatly improves the anti-interference of the gyroscope system.

The invention relates to the technical field of ultrasonic emission, and particularly provides an arbitrary waveform ultrasonic generation method for demodulating a pulse width modulation signal by using frequency response characteristics of a transducer. The method comprises the following steps: acquiring frequency response characteristic data of a target ultrasonic transducer; calculating a modulation function for modulating the duty ratio of the pulse width modulation signal; generating a high-voltage pulse width modulation signal sequence; directly driving the target ultrasonic transducer by the high-voltage pulse width modulation signal sequence, and filtering and demodulating the high-voltage pulse width modulation signal sequence by using the frequency response characteristic of a mechanical vibration system of the target ultrasonic transducer as a natural low-pass filter, and generating an ultrasonic wave corresponding to the target ultrasonic waveform. According to the invention, the fundamental simplification of the system structure is realized, high-fidelity arbitrary waveform ultrasonic output is obtained on the basis of keeping high-efficiency switch driving, and the system has excellent waveform flexibility and adaptive capacity to transducer characteristics.

The application belongs to the field of optical fiber interference measurement and phase generated carrier demodulation technology, and particularly relates to a method for improving a phase generated carrier algorithm to demodulate a low-frequency signal, which is based on three times frequency phase generated carrier mixing, uses an inverse tangent algorithm to demodulate a low-frequency signal, and is combined with an ellipse fitting algorithm to correct non-orthogonal signals and compensate linear errors in real time. In the process of demodulating a low-frequency signal, the application is not affected by carrier modulation depth and light intensity disturbance, avoids the direct current drift problem existing in traditional PGC-DCM in low-frequency signal demodulation, improves the accuracy of demodulation results, and reduces the interference of error factors.

This application relates to the field of fiber optic sensing measurement and engineering structure stress analysis technology, and particularly to a method for measuring the thermal stress of a boiler structure based on fiber Bragg grating technology. The method includes: S1 sensor deployment; S2 spectral signal transmission; S3 spectral line preprocessing; S4 center wavelength demodulation; S5 thermal stress inversion; S6 stress map reconstruction; and S7 anomaly identification. This application achieves synchronous sensing and precise decoupling of temperature and strain in high-temperature and complex environments by deploying decoupled fiber Bragg grating sensors in key stress areas of the boiler structure and introducing a Bragg reflection center wavelength response model. This response mechanism, based on the nonlinear coupling relationship between wavelength drift and temperature or strain, effectively avoids the problems of traditional thermocouples and resistance strain gauges being susceptible to temperature drift interference and having limited deployment numbers, significantly improving the accuracy and distribution integrity of thermal stress identification.