Method and system for broadcasting a digital data signal within an analog TV signal using Orthogonal Frequency Division Multiplexing
US6788349B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 12, 2001 |
| Grant date | Sep 7, 2004 |
| Priority date | — |
| Expiry date | Jul 21, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L5/0044
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention relates to a method and system for transmitting digital data within an analog TV signal. Digital data are received from a data source. The digital data are then multilevel encoded and a plurality of data symbols in dependence thereupon is provided. Each of the plurality of data symbols is modulated in frequency domain onto a carrier of a plurality of carriers such that each carrier carries a different data symbol. The modulation step is based on an OFDM method and is performed using a serial to parallel converter. After modulation a digital data signal is provided. Some carriers of the plurality of carriers are turned off in the modulation process in order to shape the spectrum of the digital data signal such that the spectrum of the digital data signal comprises notches at locations coinciding with locations of spectral components in the vestigial sideband of the video carrier of the analog TV signal. The width of the notches is determined such that degradation of the analog TV signal due to the transmission of the digital data within the analog TV signal is substantially reduced. After IFFT transformation into time domain and D/A conversion the digital data …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.