Method and apparatus for producing a pulse width modulated signal
US6473457B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 7, 1999 |
| Grant date | Oct 29, 2002 |
| Priority date | — |
| Expiry date | May 7, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M5/08
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus to produce a pulse width modulated (PWM) signal from pulse code modulated (PCM) data. In one embodiment, a crossing point of an analog signal with the ramp portion of a sawtooth waveform is approximated by first extrapolating, or projecting, a line between two adjacent sample points across other sample points to produce an estimate of the crossing point. A magnitude difference between a crossing point of the extrapolated line and a sample point magnitude on each side of the crossing point is determined. The magnitude difference, multiplied by an empirically determined constant, is added to the estimate. A PWM signal is then produced using the estimate for the crossing point.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.