Method for converting a plurality of signals from one of a digital and analogue form to the other form
US6621434B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 10, 2002 |
| Grant date | Sep 16, 2003 |
| Priority date | — |
| Expiry date | Jun 10, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/0125
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for selectively and sequentially converting digital video data signals in three formats, namely, standard definition, progressive scan and high definition formats to analogue form such that the same analogue reconstruction filter can be used for filtering the analogue forms of the signals after conversion. The digital signals prior to being converted are over-sampled at respective over-sampling frequencies for displacing image frequencies to frequencies sufficiently spaced apart from the widest band width signal so that the analogue reconstruction filter can be provided for filtering the widest band width signal as well as the other band width signals and also can be provided with a relatively low roll-off rate of attenuation. The standard definition video data signals are over-sampled at eight times the nyquist sampling frequency, and the progressive scan signals are over-sampled at four times the nyquist sampling frequency, thus displacing image frequencies of the standard definition and progressive scan signals to 108 MHz, so that the centre frequency of the image frequency is displaced to 108 MHz. The high definition video signals are over-sampled at twice the nyquist …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.