Systems and methods for detecting tampering with video transmission systems
US8576966B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 9, 2011 |
| Grant date | Nov 5, 2013 |
| Priority date | — |
| Expiry date | Jun 20, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N21/42607
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Systems and methods for controlling transmission of signals are described. A camera-side modem is configured to receive two signals from a video camera and to extract a received passband signal from a transmission line. A detector in the camera-side modem generates an alarm signal when disruption or loss of the received passband signal is identified. An enable signal is used to control transmission of at least one of the baseband video signal and the passband video signal. The passband signal may be identified by an estimate of mean square error in a quadrature amplitude demodulator, a measurement of reliability provided by a constellation detector, a measurement of reliability based on a sequence of frame synchronizations and/or an estimate of mean square error in an equalizer. The detector may monitor a gain factor in an automatic gain control module of the camera-side modern and/or a magnitude of the received passband signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.