利用逆序循环实现FFT运算中倒序算法的优化

Use Bit-Reverse Loop to realize the optimization of Bit-scramble algorithm in FFT

在数字信号处理中,FFT运算所占角色日趋重要。FFT的运算性能可以在很大程度上影响整个信号处理系统的性能。传统FFT算法中需要进行倒序以得到正确结果。倒序的运算速度取决于两个方面:逆序数的计算效率及取数存数时间。本文提出了逆序循环的概念并在此基础上提出一种新的倒序优化算法。在MPC7400芯片上进行的实验表明,采用本文提出的方法可以大大提高传统倒序算法性能。

The Fast Fourier Transform (FFT) plays an important role in Digital Signal Processing (DSP). The speed of FFT algorithm can greatly influent the performance of DSP system. Bit-scramble is needed to get correct result in traditional algorithms. The speed of bit-scramble mainly depends on two factors: the computation load for bit-reverse and the load-save time for swap data. In this paper, we have given out a new concept: bit-reverse loop and proven a new kind solution based on it. The simulation on MPC7400 has proved the new solution can improve the performance of traditional bit-scramble algorithm greatly.