FIELD: electrical communications; secure communication systems preventing unauthorized access to information signals transmitted over analog communication channels. SUBSTANCE: method includes pre-shaping of digital signals matched with communication channel, scrambling of each of them by adding to digital masking signal, their comparison with digital information signal, transmission of chosen digital signal matched with communication channel over the latter, and recovery of digital information signal. Analog signal scrambler has in sending center storage device, selecting unit, switching unit, and storage unit for digital signals matched with communication channel; in receiving center, it has adder. EFFECT: provision for eliminating distortions caused by extending signal scrambling frequency spectrum relative to information signal in case of arbitrary selection of digital masking signal. 3 cl, 20 dwg
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Authors
Dates
1998-12-20—Published
1997-10-20—Filed