Accession Number : ADD008365

Title :   Jamming of Keyed Continuous Wave Radio Signals.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE ARMY WASHINGTON DC

Personal Author(s) : O'Donnell,Richard V

Report Date : 22 Jul 1980

Pagination or Media Count : 4

Abstract : This invention relates to a method and apparatus for jamming enemy radio transmissions and more particularly to a method and circuitry for rendering radio signals of the keyed continuous wave (CW) type unintelligible to the enemy while permitting the jamming station to read the enemy transmission. The conventional method of jamming keyed CW signals is to transmit another CW signal which is randomly keyed by the jammer. The speed of the random keying must be adjusted by the jammer operator to the approximate keying speed of the victim signal to be most effective. This of course prevents true random keying. Further, with this method of jamming the intelligence in the transmitted signal is made unavailable to friend and foe alike. These and other disadvantages are overcome in the method and apparatus of the present invention. Briefly stated, the present invention comprises a jamming transmitter which is automatically controlled by the victim signal in such a manner that the jamming transmitter goes on for a predetermined period each time that the victim signal goes off. Thus at the end of each dot, dash or mark in the enemy code transmission, the jamming transmitter would produce a pulse of RF approximately equal in length to the shortest space of said code transmission. Thus the jamming transmitter 'fills-in' the spaces in the victim signal and masks the intelligence therein. The operation of the jamming transmitter is controlled by a jamming receiver. Since the transmitter is on only while the victim signal is off the receiver output will compromise the original unjammed enemy signal.

Descriptors :   *Patents, *Radio jamming, *Pulse code modulation, *Radio signals, Continuous waves, Radio transmission, Operators(Personnel), Stations, Length, Jamming, Enemy, Transmitters, Inventions, Signals, Receivers, Coding

Subject Categories : Acoustic Detection and Detectors
      Radio Countermeasures

Distribution Statement : APPROVED FOR PUBLIC RELEASE