Method and device for calculating a discrete orthogonal transformation such as FFT or IFFT
View Patent ↗The invention comprises a method for calculating an orthogonal discrete transform on the basis of the DIT method in prescribed intermediate steps with the following steps: the data are read from a memory organized on page-for-page basis; the intermediate step prescribed by the transform is carried out; the resulting data are stored in a buffer memory; and the resulting data are written page-for-page from the buffer memory to the memory organized on a page-for-page basis. Suitable discrete orthogonal transforms are FFT, IFFT, DCT, IDCT and transforms of similar structure.
1. A method for calculating an orthogonal discrete transform on the basis of the DIT method in prescribed intermediate steps,
wherein
a) the data are read from a memory organized on a page-for-page basis,
b) the intermediate step prescribed by the transform is carried out,
c) the resulting data are stored in a buffer memory, and
d) the resulting data are written page-for-page from the buffer memory to the memory organized on a page-for-page basis.
2. The method as claimed in claim 1 , wherein the discrete orthogonal transform is formed by an FFT, IFFT, DCT or IDCT.
3. The method as claimed in claim 2 , wherein the transform has an identical geometry for each stage.
4. The method as claimed in claim 3 , wherein an FFT or IFFT based on Singleton is used.
5. An apparatus for carrying out the method as claimed in claim 1
wherein
the apparatus has a memory organized on a page-for-page basis, a processor and a directly organized memory which is arranged downstream of the processor.
6. The apparatus as claimed in claim 5 , wherein the page-oriented memory is a large memory in relation to the directly organized buffer memory.
7. The apparatus as claimed in claim 6 , wherein a fast memory is used for the buffer memory.
8. The apparatus as claimed in claim 5 , wherein the page-oriented memory is a dram and buffer memory is an SRAM.
9. The apparatus as claimed in claim 5 , wherein the page-oriented memory has a size of 8 K addresses and the buffer memory has a size of 32-64 addresses.
10. The apparatus as claimed in claim 5 , wherein the processor provides a Butterfly.
11. An apparatus for carrying out the method as claimed in claim 1
wherein
the apparatus has a memory organized on a page-for-page basis, a processor and a directly, organized memory which is arranged upstream of the processor.
12. A method for calculating an orthogonal discrete transform on the basis of the DIF method in prescribed intermediate steps,
wherein
a) the data are read from a memory organized on a page-for-page basis,
b) the data are stored in a buffer memory,
c) the intermediate step prescribed by the transform is carried out, and
d) the resulting data are written page-for-page from the buffer memory to the memory organized on a page-for-page basis.
13. A method for calculating an orthogonal discrete transform on the basis of the DIF method in prescribed intermediate steps,
wherein
the data are read from two memories organized on a page-for-page basis, such that the reading is organized on a page-for-page basis, the intermediate step prescribed by the transform is carried out, and
the resulting data are again written page-for-page to the two memories organized on a page-for-page basis.
14. An apparatus for carrying out the method as claimed in claim 13
wherein
the apparatus has two memories organized on a page-for-page basis and a processor.
15. The apparatus as claimed in claim 14 , wherein the page-oriented memories are of the same size.
16. The apparatus as claim in claim 15 , wherein the page-oriented memory has a size of 4 K addresses.