Digital circuit for simultaneously generating digital sine- and cosine-function values
US4827442A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 8, 1987 |
| Grant date | May 2, 1989 |
| Priority date | — |
| Expiry date | Sep 8, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/643
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
This circuit simultaneously provides the sine- and cosine-function values for one and the same digital argument from any of the quadrants of the sine and cosine functions. Stored in the two halves of a read-only memory are the unsigned function values of the first half-quadrant of the cosine function in the direction of increasing arguments and of the second half-quadrant in the direction of decreasing arguments, respectively. The number of bits of the argument is greater than the number of bits of the function values, including the sign bit, by two. By skillful inversion of the addresses and the read-out function values using multiple-inverter blocks in conjunction with multiple-switch units sine- and cosine-function values can be generated for all four quadrants both in the one's and in the two's complement code. If the argument is formed by an accumulator fed with the frequency determining digital word, the digital circuit is a digital sine-/cosine-wave oscillator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.