Accession Number : ADD006792

Title :   Anti-Jamming Communication System.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON DC

Personal Author(s) : Hobbs,Charles F

Report Date : 18 Dec 1979

Pagination or Media Count : 13

Abstract : In the practical embodiment of the invention, several frequency channels are occupied simultaneously but for only very brief intervals of time so that only a relatively small amount of interference would be experienced on existing communication facilities. Protection against spot jamming is afforded by dodging over a wide frequency range with each of the several channels. Thus the invention provides for redundant transmission of digital information on several channels, each of which are dodging in a psuedo-random and apparently unrelated manner over a relatively large frequency-time message space. It combines the inherent reliability of time synchronization with the high information rate capability of message directed dodging over the frequency-time message space. Since there is only a small probability of two or more secondary stations being tuned to the same combination of channels at the same time, it is not necessary to transmit the address digits. They are used only to select the proper channels at the master station. In addition to making more capacity available for transmitting message digits, this feature increases the difficulty of any possible analyst since it is not known to which secondary station a given transmission is being directed.

Descriptors :   *Patents, *Communication and radio systems, *Secure communications, *Radio antijamming, Digital systems, Frequency agility, Pseudo random systems

Subject Categories : Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE