摘要目的 眼科高频超声数字化成像中使用内插滤波器可等效地提高采样率以节约资源.方法 在研究分析了级联积分梳状(CIC)滤波器的基础上,结合运用余弦(COSINE)滤波器和内插二阶多项式(ISOP)滤波器对其进行改进.结果 通过硬件描述语言描述改进后的高效结构,并在现场可编程门阵列(FPGA)中实现,最后通过实验仿真验证该内插变频算法的有效性.结论 改进后的CIC滤波器基本保留了效率和资源节约方面的优势,同时也改善了其通带宽度和阻带衰减特性,能够适用于10 MHz的高频眼科超声信号处理的要求.

abstractsObjective The aim of this study was to improve cascaded integrator comb (CIC) interpolation filter for the enhancement of sampling frequency in the ophthalmology ultrasonagraphy digital imaging system. Methods CIC filter was improved base on the analysis of it and the combined introduction of COSINE and interpolated second-order polynomials(ISOP) filters. Results The modified structures were implemented in field programmable gate array(FPGA) using verilog hardware description language. The algorithm was validated by simulation. Conclusion The results showed that the improved CIC not only had the advantage of high efficiency and saving more resources, but also ameliorated its pass band and stop band. It is applicable in high frequency uhrasonography digital signal processing.