Variable-length fast fourier transform circuit and implementation method

Abstract

The invention discloses a fast fourier transform circuit which is used for a fast fourier transform of variable-length sequence points, and the circuit comprises a mixed-base operation module, a base combination selection module and a control module, wherein the mixed-base operation module comprises a plurality of base operation units with different base numbers; the base combination selection module selects a combination of the base operation unit according to the number of points of a sequence to be operated; and the fast fourier transform is carried out on the sequence points by utilizing the selected base operation units through the control module. The base operation unit adopted in the invention is variable and selectable, namely the fast fourier transform is carried out on 2n point by a mixed base, and the high-speed low-time delay fast fourier transform circuit is implemented by utilizing relative lower hardware cost. The fast fourier transform circuit has great flexibility, and can perform variable-length fast fourier transform (FFT) operation.

Description

【Technical field】 [0001] The invention relates to the field of digital signal processing, in particular to a variable-length fast Fourier transform circuit and a realization method. 【Background technique】 [0002] The Fourier transform is a form of transforming a signal from the time domain to the frequency domain, and is an important analysis tool in the fields of acoustics, imaging, telecommunications, and signal processing. Among them, discrete Fourier transform (DFT) is one of the indispensable tools in the field of digital signal processing, especially the emergence of fast Fourier transform (FFT) makes DFT widely used. Using the FFT algorithm can greatly reduce the number of multiplications required by the computer to calculate the DFT, especially the more points in the sequence points to be transformed, the more significant the savings in the calculation of the FFT algorithm. [0003] In more detail, for a sequence X(n) with a length of N points, where n is an intege...

AI Technical Summary

Problems solved by technology

That is to say, a radix-4FFT circuit or FFT processor using a radix-4 base operation unit can only L The sequence points are calculated, but the number of points cannot be 2 L All sequence points are calculated; the radix-8FFT using the radix-8 base operation unit can only be used for the number of points is 8 L The sequence points are calculated, but the number of points cannot be 2 L or 4 L All sequence points of

That is to say, these FFT circuits or FFT processors have limitations on the number of sequence points that can be processed, which cannot meet the applications in some cases.

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