关键词: 数字滤波器, 正则有符号数, 定点系数, 最小均方根

Abstract: In order to save the resources of the Finite Impulse Response (FIR) filter and increase the running speed, it was proposed to use the Least Mean-Square-Error (LMSE) to transfer the float point coefficients filter to the Canonical Signed Digit (CSD) filter. The FIR filter was implemented by the cascades structure, which conjugated pairs of zeros into two basic sections. First, all zeros of the digital filter were calculated, which were made of two cascade sections for an FIR. And then the coefficients of the first cascade were transferred to fixed point. Next step was to quantize the second cascade coefficients into fixed point. To eliminate the finite word-length effects, the LMSE was adopted to compensate zeros in this step. Finally, all the fixed point coefficients were quantized into CSD. In order to prove the effectiveness of the two methods, and the FIR filter was also designed with simple quantized coefficients. The magnitude responses of two methods show that the LMSE quantization is more effective than that of the simple quantization.

Key words: digital filter, Canonical Signed Digit (CSD), fixed point coefficient, Least Mean-Square-Error (LMSE)