A Vibration Sensing Demodulation Method Based on Light Intensity Difference of CCD Pixel Points

Vibration sensing networks, which consist of numerous sensors, require high demodulation speeds. Therefore, optimizing the demodulation algorithm to reduce data processing volume or complexity is crucial for enhancing efficiency and performance. This article proposes a vibration sensing demodulation method based on the light intensity difference (LID) of charge-coupled device (CCD) pixel points. The method requires calculating the center wavelength of all CCD pixel points only once. It then selects pairs of pixel points with opposite phases in the reflection spectrum to perform differential operations, significantly reducing data processing volume and computational complexity and thereby improving demodulation speed. In addition, by increasing the number of calculation pairs, the method enhances demodulation resolution, suppresses noise, and improves robustness. The method is modeled through simulation and theoretical analysis, with results indicating reduced background noise influence. Tested with fiber Bragg grating (FBG) vibration sensors, the method achieves a resolution of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$62~\mu $ </tex-math></inline-formula>g and a demodulation rate of 16 kHz, highlighting its promising application prospects in high-speed and large-capacity vibration sensing.