1results about How to "High resolution measurement" patented technology

This invention relates to a phase-sensitive optical time-domain reflectometer based on orthogonal frequency division multiplexing (OFDM) pulse coding. A continuous laser beam is split into a local path and a probe path via an optical coupler. The probe path, driven by a radio frequency signal, generates multiple frequency-orthogonal intensity-coded pulse sequences through an optical intensity modulator. These sequences are arranged sequentially in time, possessing the same symbol information but different chip sequences. The Rayleigh backscattered light generated by the pulse sequences entering the sensing fiber under test undergoes coherent interference with the local light in an optical bridge and polarization diversity module. The signal acquisition circuit utilizes an unmatched filter to achieve pulse compression and Rayleigh scattering signal separation, and synthesizes the results of the pulse coding sequences at each frequency to obtain the strain signal. Compared with existing technologies, this invention achieves pulse compression by designing an unmatched filter, improving the signal-to-noise ratio while maintaining spatial resolution. Furthermore, by synthesizing the results of orthogonal frequency pulse sequences, coherent fading is eliminated, achieving fading-free, high signal-to-noise ratio strain measurement.