Method for converting a video signal from one of an analogue and digital form to the other of the analogue and digital form with enhanced signal to noise ratio
US6707407B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 2002 |
| Grant date | Mar 16, 2004 |
| Priority date | — |
| Expiry date | Jun 11, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/50
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for converting multi-bit digital video data signals to analogue form wherein the video data signals are in three formats, namely, standard definition, progressive scan and high definition formats, which permits a relatively low order analogue reconstruction filter to be used for filtering the analogue form of the signal. The three formats of the digital video data signals are over-sampled at relatively low over-sampling rates, the standard definition video signals being over-sampled at eight times the nyquist sampling frequency, the progressive scan format signals being over-sampled at four times the nyquist sampling frequency, while the high definition format signals are over-sampled at twice the nyquist sampling frequency. By virtue of the fact that the Video data signals are over-sampled at relatively low over-sampling rates, the over-sampled signals are subjected to sigma-delta modulation in a relatively low order sigma-delta modulator, namely, a second order sigma-delta modulator for noise shaping the quantisation noise. This, thus, permits the analogue reconstruction filter to be provided as a third order filter, and thus of relatively low order.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.