MR. JAMES H FARMER, PA
Physician Assistant at Collier Rd, Atlanta, GA

4636852, Jan 13, 1987

Jan 26, 1984

6/574211

James O. Farmer - Doraville GA

Scientific-Atlanta, Inc. - Atlanta GA

H04N 7167

358120

A scrambled TV signal is provided by adding thereto a signal having an amplitude which changes pseudorandomly in successive increments of time, the duration of each of which is much less than the horizontal line duration of the TV signal. This signal encompasses substantially the entire duration of the TV signal and has an amplitude during horizontal and substantially the entire vertical sync interval to suppress the horizontal and vertical sync pulses to picture level. The pseudorandom signal is generated synchronously with the TV signal on a frame basis and synchronizing pulses are transmitted during the vertical interval together with a pulse for amplitude calibration. A matching pseudorandom signal is generated in synchronism with the pseudorandom component of the scrambled TV signal. The synchronizing pulses and the calibration pulse operate circuits which effect synchronization and amplitude control in the generation of the matching signal. The matching signal is subtracted from the scrambled TV signal to provide a descrambled signal for reception.

4888799, Dec 19, 1989

Jan 3, 1986

6/815912

Joseph G. Mobley - Dunwoody GA
Anatoly Kozushin - Duluth GA
Saeed Baher - Atlanta GA
Steve Addison - Atlanta GA
Howard Paulk - Woodstock GA
James Farmer - Doraville GA

Scientific Atlanta, Inc. - Atlanta GA

H04K 104

380 6

The present invention is directed to an inversion scrambler and unscrambler having pseudo-randomly controlled polarity-reversing switches to invert and re-invert, respectively, an audio signal so as to restrict the intelligent dissemination of the audio signal. To improve security of the scrambled signal, the audio signal is concealed prior to scrambling. Concealment includes clamping the original audio signal to a predetermined value and optionally offsetting this clamped signal prior to scrambling. The concealed signal is scrambled by inverting contiguous portions of the signal at pseudo-random intervals, accomplished by a polarity-reversing switching network controlled by a pseudo-random code generator. Upon unscrambling, artifacts will appear at the inversion points of the unscrambling signal, due to bandwidth limitations inherent in any transmission path. To mask the artifacts, track-and-hold circuitry is used to sample the unscrambled audio signal waveform level just prior to the artifact and hold this level throughout the short period when the artifact would occur.

4691353, Sep 1, 1987

Feb 25, 1985

6/704817

James O. Farmer - Doraville GA

Scientific Atlanta, Inc. - Atlanta GA

H04N 7167

380 15

In a TV signal scrambling system for use in a CATV network wherein premium programs are transmitted over cable, by broadcast transmission and the like with the sync pulses of the color TV signals suppressed, a processor is provided which processes the color components separately from the luminance and sync components so as to remove coherency (constant phase relationship) between the color subcarrier and the sync pulses. The separately processed components with the coherency removed are recombined to provide the composite TV signal which is scrambled and transmitted to the subscribers. Subscribers having television receivers of the type which recover sync signals by count down techniques from the color subcarrier, such as those using some integrated circuits (chip sets) are then made unable to recover the sync pulses unless equipped with an authorized descrambler. Unauthorized subscribers who are equipped with digital television receivers therefore obtain a scrambled TV picture which rolls horizontally across the screen.