Cryptography – Key management – Having particular key generator
Patent
1983-12-30
1987-03-31
Buczinski, Stephen C.
Cryptography
Key management
Having particular key generator
380 34, 332 23A, 375 39, 370 20, H04N 7167
Patent
active
046547053
ABSTRACT:
A two channel audio scrambling circuit for a television signal encoding system includes synchronized digital carrier switching means for deriving two suppressed carrier, switched audio signals that are 90 degrees apart, and combining them into a single output signal. A digital phase shifter, supplied with a carrier related to the horizontal line frequency develops properly phased outputs for controlling electronic switches to produce two phase displaced digital carrier switching signals. A plurality of scrambling modes are determined by logic means under control of a vertical interval signal, a video inversion signal and a tone signal input for controlling the digital phase shifter to change the carrier frequency. Complementary decoding circuitry for recovering the so-encoded audio signals is also described.
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"Stereophonic TV Sound", Electronics, 10/30/59.
Forbes Ronald L.
Lund John A.
Mann, III Harold E.
Buczinski Stephen C.
Lewis Aaron J.
Zenith Electronics Corporation
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