Interdiction method and apparatus with mode control for variable frequency elements
US5317635A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 10, 1992 |
| Grant date | May 31, 1994 |
| Priority date | — |
| Expiry date | Jun 10, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04K2203/14
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An off-premises method and apparatus for the interdiction of unauthorized channels of a broadband cable television signal includes common circuitry for adjusting the amplitude and equalization levels of the broadband CATV signals and one or more subscriber modules for generating jamming signals of different frequencies which are used to interdict one or more unauthorized channels. Each subscriber module is associated with a subscriber and is programmable and addressable to adjust the jamming parameters of that subscriber independently of other subscribers. Each subscriber module circuit comprises a plurality of latches, each of which is associated with one of a plurality of digital to analog converters. Each of the digital to analog converters drives one or more frequency agile oscillators with its analog output to generate the jamming signals. The subscriber module is based on a sequential state machine which loads frequency control words corresponding to the jammed channels from a frequency control memory into each latch on a cyclic basis. The state machine is adapted to vary the sequence in which frequency control words are read out of the memory to modify the jamming pattern of…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.