Method for dividing ROM and DDFS using the same method
US6615398B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 2001 |
| Grant date | Sep 2, 2003 |
| Priority date | — |
| Expiry date | Feb 5, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2101/04
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The present invention relates to a ROM division method for reducing the size of a ROM in a direct digital frequency synthesizer (DDFS), which is used to synthesize a frequency in a communication system requiring fast frequency conversion. A ROM consuming most energy in the system, a modified Nicholas architecture is brought forth to reduce the size of ROM. In this modified Nicholas architecture, a ROM is divided into coarse ROM and fine ROM to convert phase to sine value. The present invention divides the coarse ROM and the fine ROM into quantized ROM and error ROM respectively. Then, value stored in each ROM is segmented in certain intervals and the minimum quantized value in each of the section is stored in the quantized ROM, while the difference between the original ROM value and the quantized ROM value is stored in the error ROM. This way, the size of a ROM can be reduced. Phase value inputted in a DDFS, a sine value is calculated by adding the four ROM values, i.e., coarse-quantized ROM, coarse-error ROM, fine-quantized ROM and fine-error ROM.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.