一种可配置数字滤波器设计及其ASIC实现

摘要

针对一种行业专网用带宽可变频点可变无线射频芯片的需求,设计一种可配置数字滤波器系统结构.该结构通过CIC滤波器组减少系统中FIR滤波器的阶数和系数,并采用补偿滤波器和增益校正模块减小信号失真;带宽通道配置模块选取CIC滤波器组的抽取因子、FIR滤波器系数等参数,实现带宽可变、频点可变的功能.采用Global Foundry 0.18μm工艺进行ASIC设计,通过系统优化减少数字滤波器内部数据位宽,并采用CSD编码系数等面积优化方法,使版图面积减少30%.研究结果表明:所设计数字滤波器实现了5 kHz~2 MHz等带宽信号的选取,其通带波纹小于0.015 dB,阻带衰减大于55 dB,过渡带宽不大于通带宽度.%A configurable digital filter structure was designed based on the request of variable bandwidth and frequency RF Chip for application of industry network. By using CIC filter group, the order and coefficient of FIR filter were reduced, and the signal distortion was also reduced due to the compensation filter and gain correction module. CIC filter decimation factor, FIR filter coefficients and other parameters were selected by bandwidth channel configuration module to achieve the function of variable bandwidth and frequency. The chip was implemented in Global Foundry 0.18 μm process. The internal data bits of the digital filter were reduced by data width matching module. And the layout area of the digital filter was reduced by 30%using CSD coding multiplication method, etc. The results show that the digital filter achieves bandwidths of 5 kHz-2 MHz, passband ripple is less than 0.015 dB, stopband attenuation is greater than 55 dB, and transition bandwidth does not surpass the pass bandwidth.