基于近似计算的精度动态可调FFT处理器  

An Accuracy Dynamically Configurable FFT Processor Based on Approximate Computing

作　　者：马丽萍 张骁煜 白雨鑫 陈鑫[1] 张颖[1] MA Liping;ZHANG Xiaoyu;BAI Yuxin;CHEN Xin;ZHANG Ying(College of Electronic and Information Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)

机构地区：[1]南京航空航天大学电子信息工程学院,南京210016

出　　处：《上海交通大学学报》2022年第2期223-230,共8页Journal of Shanghai Jiaotong University

基　　金：模拟集成电路重点实验室基金(61428020304);国家自然科学基金(61106029,61701228);航空科学基金(20180852005)资助项目。

摘　　要：为满足多种场景对电路指标的不同需求,基于近似电路理念提出一种精度可调快速Fourier变换(FFT)处理器.首先,在蝶形节点和旋转因子乘法节点上分别提出了一种截断进位链的可配置近似蝶形计算单元和一种位宽可调的乘法模块.通过MATLAB搭建误差分析平台,详细分析了在各个蝶形节点和旋转因子节点对近似计算的敏感程度,确定了FFT处理器的5种计算模式,实现性能、功耗与精度等参数的动态调节.最终,所提设计在台积电(TSMC)180 nm互补金属氧化物半导体(CMOS)工艺下通过超大规模数字集成电路标准流程实现,性能结果由专业电子自动化设计(EDA)工具评估得到,相对于精确模式,处理器在近似模式下的最高工作频率提升约14.33%;当工作频率为60 MHz时,功耗降低约15.61%.In order to meet the different requirements of circuit targets in various scenarios,an accuracy configurable fast Fourier transform(FFT)processor based on the concept of approximate circuit is proposed.A configurable approximate butterfly unit which can truncate the carry chain is proposed at the butterfly node and a bit-width configurable multiplier is proposed at the rotation factor multiplication node.MATLAB is adopted to develop an error analysis platform.After analyzing the sensitivity of each butterfly node and rotation factor node to approximate calculations,five calculation modes of the accuracy configurable FFT processor are determined,which can achieve dynamic balance among performance,power consumption,and accuracy.Finally,based on the 180 nm complementary metal oxide semiconductor(CMOS)technology of Taiwan Semiconductor Manufacturing Company(TSMC),the proposed processor is implemented with the standard procedure of ultra-large-scale digital integrated circuits.The performance results are obtained by professional electronic design automation(EDA)tools.Compared with the precise mode,the maximum operating frequency of the processor in the approximate mode is increased by 14.33%,and the power consumption is reduced by 15.61%when the operating frequency is 60 MHz.

关 键 词：近似电路 快速FOURIER变换 精度动态可调 近似蝶形计算单元 位宽可调 

分 类 号：TN47[电子电信—微电子学与固体电子学]