用于相位调制型光纤电流互感器的数字梳状滤波器

传统的相位调制型光纤电流互感器普遍存在噪声电流大、信噪比低、小电流测量能力差的问题。通过比较被测电流和噪声电流不同的频谱特征，提出了一种可实现的数字梳状滤波器，它位于光电转换级之后，信号解调级之前。阐释了这种滤波器的特点，分析了它对被测电流的滤波能力，计算了它的频域和时域特征，并提出了在硬件中实现的方法。通过仿真，对比了不同阶数梳状滤波器的滤波效果、频带宽度以及算法复杂度。在光纤电流互感器硬件中具体实现了这种滤波器，通过对比试验验证了滤波算法的有效性和可行性。

Digital Comb Filter for Phase-Modulated Fiber Optic Current Transformer

Traditional phase-modulated fiber optic current transformers have problems of large noise current, low signal-to-noise-ratio and weak capability of small current measurement. By the comparison of the frequency spectrums of measured current and noise current, a realizable digital comb filter is proposed. It locates between the conversion stage and the demodulation stage. The characteristics of this filter is explained. The capability of filtering the measured current is analyzed. The time domain character is computed. The realization scheme is put forward. Filtering effect, spectrum bandwidth and algorithm complexity of different orders filters are compared by simulation. This filter is realized in the hardware of the fiber optic current transformer. The effectivity and feasibility of this fiter algorithm are verified through comparative experiment.