Research On High Energy Efficiency Analog Computing Unit

Fast Fourier transform(FFT)is essential in multi-carrier radio frequency transform systems,especially in orthogonal frequency division multiplexing(OFDM)systems.But almost all transform systems implement the FFT algorithm in the digital domain.Compared to the implementation in the digital domain,the implementation in the analog domain has greater advantages in terms of speed and power consumption.At the same time,in addition to the application in the multi-carrier radio frequency system,the realization of the FFT algorithm in the analog domain also brings a new design dimension and method to the design of the hybrid filter bank.This thesis firstly outlines the basic structure of the FFT algorithm and the complexity comparison of each algorithm.Secondly,the evaluation criteria and non-ideal factors of the Analog Fast fourier transform(AFFT)are listed.And then,several specific AFFT implementations are listed,and the characteristics and design difficulties of various implementations are summarized also.According to the structure,a complete system behavior-level modeling and simulation is carried out for this design unit.Finally,according to the results of the system modeling,the specific circuits of the 16-channel and 64-channel AFFT calculation units based on the radix-4 time decimation FFT algorithm are proposed.Under the 28nm-based process,16-channel and 64-channel AFFT circuit designs have been completed respectively.According to the working principle of pipeline,the sampling rate is 250MS/s and 1GS/s respectively.Under 900 m V supply voltage,the simulation results show SNDRs of 50 dB and 53 dB,separately.