High speed, low power direct digital synthesizer
US5467294A · kind A · utility
Inventors
Key dates
| Filing date | Mar 9, 1994 |
| Grant date | Nov 14, 1995 |
| Priority date | — |
| Expiry date | Mar 9, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/2841
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus suitable for generating programmable digital sine waves which involves converting the output of a direct digital synthesizer or numerically controlled digital oscillator to a higher frequency with a multiplier-less structure that takes advantage of the properties of trigonometric identifies for sine and cosine. Sine waves are generated digitally using a phase accumulator which is clocked at one fundamental frequency. The phase accumulator input provides a control word which determines the intermediate frequency of the direct digital synthesizer output. Taking advantage of the periodicity of the phase accumulator operation, the outputs of the accumulator are utilized to address a read only memory ROM lookup table which produces in-phase and quadrature samples of the sine wave at the intermediate frequency. The in-phase and quadrature samples are then complemented (i.e. negated) to produce an additional set of in-phase and quadrature samples which are 180.degree. out of phase from the original samples. Switching between these four possible outputs at a higher fundamental clock frequency results in the translation of the intermediate frequency output to a higher…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.