Methods and apparatus for fast fourier transforms
US6609140B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 30, 2000 |
| Grant date | Aug 19, 2003 |
| Priority date | — |
| Expiry date | Aug 10, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F17/142
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system for calculating fast Fourier transforms includes a non-final stage calculating means for repetitively performing in-place butterfly calculations for n−1 stages as well as a final stage calculating means for performing a final stage of butterfly calculations. The final stage calculating means includes a first loop and a second loop. The first loop performs a portion of the final stage butterfly calculations by iterating on a table of first loop index values consisting of values that bit-reverse into themselves. The first loop also includes control logic to select inputs for groups of butterfly calculations based on the first loop index values. The second loop performs a remaining portion of the final stage butterfly calculations by iterating on a table of second loop index value pairs consisting of two values that bit-reverse into each other. The second loop includes control logic to select inputs for two groups of butterfly calculations based on the two second loop index pair values respectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.