Discrete cosine transformer
US4797847A · kind A · utility
Inventor
Key dates
| Filing date | Feb 4, 1987 |
| Grant date | Jan 10, 1989 |
| Priority date | — |
| Expiry date | Feb 4, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T9/007
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The device is applicable to data compression. It computes the discrete cosine transform X of a signal x represented by N digitized samples x, . . . x, . . . x, where N is a power of 2: ##EQU1## the device includes a convolver for convolution between the samples xi and a stored sequence of samples wi (N) and a set of identical elementary circuits grouped in serveral banks. Each circuit is a "butterfly" having two inputs and two outputs one of which delivers the sum and the other the difference of the two inputs. The elementary circuits of the first bank receive at their two inputs the samples of the convolution product whose indices are separated by N/2 from each other.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.