Cryptography – Particular algorithmic function encoding – Nbs/des algorithm
Patent
1991-04-09
1993-07-20
Gregory, Bernarr E.
Cryptography
Particular algorithmic function encoding
Nbs/des algorithm
380 10, 380 20, 380 28, 380 43, H04N 716
Patent
active
052300196
ABSTRACT:
A key signal conversion device for use in a CATV television system in which more than one different scrambling process is performed, the conversion device receiving one of a scrambled high-frequency signal in a television system and a sound intermediate frequency signal in the television system, extracting a key signal for unscrambling the scrambling in the television system and adding the key signal to a nonscrambled television signal which is to be subsequently scrambled by a process other than a process used to scramble the received signal, the key signal conversion device including: a first detecting circuit, for receiving the one of a scrambled television signal and a sound intermediate frequency signal, and for detecting one of a synchronizing signal of the television signal and a synchronizing signal superimposed on the sound intermediate frequency signal; a gate circuit, for receiving the one of a scrambled television signal and a sound intermediate-frequency signal, and for extracting the key signal therefrom using the synchronizing signal detected by the first detecting circuit; a second detecting circuit, for receiving the nonscrambled television signal, and for detecting a synchronizing signal thereof; and an inserting circuit for superimposing the key signal on the nonscrambled television signal in a predetermined horizontal interval in the vertical blanking interval of the nonscrambled television signal by the gate circuit using the signal detected by the second detecting circuit.
REFERENCES:
patent: 4621285 (1986-11-01), Schilling et al.
patent: 4736422 (1988-04-01), Mason
patent: 4802215 (1989-01-01), Mason
patent: 4839922 (1989-06-01), Imasaki et al.
Kajita Harumasa
Kariya Tetsuo
Kawashima Ichiro
Nakanami Satoshi
Tanaka Masami
Gregory Bernarr E.
Matsushita Electric - Industrial Co., Ltd.
LandOfFree
Key signal conversion device for CATV system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Key signal conversion device for CATV system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Key signal conversion device for CATV system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1766736