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US 4,397,034 AGranted
Low probability of intercept transmitting apparatus
AssigneeSperry Corporation
InventorsBenjamin V. Cox, Billie M. Spencer, John W. Zscheile, Jr.
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Abstract
A system for transmitting desired information is provided which has a very low probability of being intercepted. The system combines a well known narrow bandwidth directional antenna for limiting the interception of the main beam information signal with a novel random noise generated signal which guarantees that the sidelobe signals which also contain the desired information cannot be distinguished as information signals.
Claims7
A low probability of intercept transmitting apparatus, comprising:
- a source of data information,
- a local oscillator adapted to provide a carrier frequency,
- a first modulator coupled to said local oscillator and to said data information for providing a main modulated data signal,
- a directional antenna coupled to said main modulated data signal for transmitting main data signals and producing a desirable main beam signal and undesirable sidelobe signals,
- a source of random noise signals having the same statistical waveform characteristics as said data information,
- a second modulator coupled to said local oscillator and to said random noise signals for providing a random modulated masking signal, and
- an omni-directional antenna colocated with said directional antenna for transmitting said masking signal and for masking said sidelobe signals.
4 more elements
Dependencies are inferred from the claim text.