System and method for inserting and recovering an add-on data signal for transmission with a video signal
US5539471A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 3, 1994 |
| Grant date | Jul 23, 1996 |
| Priority date | — |
| Expiry date | May 3, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/081
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A system and method for inserting a data signal into a preexisting video signal in a transmitter so that the data signal is transmitted along with the video signal. The data signal is inserted into an unused portion of the video signal spectrum. The data signal is separated from the video signal in a receiver and may be used for any purpose, even purposes unrelated to the video signal. The data signal is filtered to create a filtered data signal having spectral characteristics that correspond to the unused portion of the video signal spectrum. The filtered signal modulates a carrier signal whose frequency is selected to permit direct insertion of the modulated filtered data signal into the video signal spectrum. In the receiver, the video signal is processed in a normal manner; and the data signal is undetected by normal television receivers. A signal separator separates the filtered data signal from the combined video signal, and an inverse filter recovers the original data signal. In one embodiment, a comb filter is used to generate the filtered data signal with 60 Hertz peaks. An inverse comb filter in the receiver recovers the original data signal. A recirculating buffer may al…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.