Cryptography – Cryptanalysis
Patent
1992-06-10
1994-05-31
Swann, Tod R.
Cryptography
Cryptanalysis
380 20, H04N 7167
Patent
active
053176359
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 the subscriber. Corresponding to each frequency control word in the memory is stored one or more mode control bits which are read out contemporaneously with the frequency control words. The mode control bits are used to allow a single digital to analog converter to control one or more voltage control oscillators with different frequency ranges, or to allow control of a single voltage control oscillator with multiple frequency ranges.
REFERENCES:
patent: 3760097 (1973-09-01), Burroughs et al.
patent: 3896262 (1975-07-01), Hudspeth et al.
patent: 3899633 (1975-08-01), Sorenson et al.
patent: 3989887 (1976-11-01), Murphy
patent: 4039954 (1977-08-01), den Toonder
patent: 4091413 (1978-05-01), Herman
patent: 4148064 (1979-04-01), Reed
patent: 4334322 (1982-06-01), Clark, III
patent: 4342119 (1982-07-01), Seidl
patent: 4343042 (1982-08-01), Schrock et al.
patent: 4367557 (1983-01-01), Stern et al.
patent: 4434436 (1984-02-01), Kleykamp et al.
patent: 4450481 (1984-05-01), Dickinson
patent: 4498193 (1985-02-01), Richardson
patent: 4521809 (1985-06-01), Bingham et al.
patent: 4651204 (1987-03-01), Uemura
patent: 4737990 (1988-04-01), Kaneko
patent: 4769838 (1988-09-01), Hasegawa
patent: 4792971 (1988-12-01), Uemura
patent: 4825468 (1989-04-01), Ellis
patent: 4837820 (1989-06-01), Bellavia, Jr.
patent: 4841569 (1989-06-01), Wachob
patent: 4903297 (1990-02-01), Rist et al.
patent: 4912760 (1990-03-01), West, Jr. et al.
patent: 4914695 (1990-08-01), Martin
patent: 4963966 (1990-10-01), Harney et al.
patent: 5014309 (1991-05-01), West, Jr.
patent: 5068893 (1991-11-01), West et al.
patent: 5109286 (1992-04-01), West, Jr. et al.
patent: 5140633 (1992-08-01), Gurusami et al.
patent: 5142574 (1992-08-01), West, Jr. et al.
patent: 5233652 (1993-08-01), Huang et al.
"Addressable Tap IT-1-SM" by Control Com, Inc.
"Tier Guard System" by E-Com Corporation.
Robertson Neil C.
Schutte Mark E.
Stirling Ronald C.
Scientific-Atlanta, Inc.
Swann Tod R.
LandOfFree
Interdiction method and apparatus with mode control for variable does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Interdiction method and apparatus with mode control for variable, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Interdiction method and apparatus with mode control for variable will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1633888