METHOD AND DEVICE FOR SECURE RADIO COMMUNICATIONS Russian patent published in 1998 - IPC

FIELD: radio engineering; low-speed radio communication links using very-low-frequency bands. SUBSTANCE: method involves shaping signal in the form of combination of monochrome components and radiating it into space. On receiving end, received signal is subjected to three-fold selection, first at carrier frequency, second after transfer of spectrum to lower frequency region, and third channel-by-channel selection. Upon identification and processing, signal is recorded at terminal. Device implementing this method has on sending end control unit, 2, high-frequency oscillator unit 3, adder 4, and power amplifier 5. On receiving end, it has preselection unit 9, group-selection unit 13, channel-by-channel selection unit 14, and identifier 16. Operation on receiving and sending centers is synchronized by means of synchronizing units 19 and 7. EFFECT: improved security of very-low- frequency radio links, reduced power requirement. 11 cl, 16 dwg