Noise radars
AssigneeGEC Avionics Limited
InventorWilliam J. McClintock
Life of this patent
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Abstract
In a noise radar a pseudo-random sequence is generated repeatedly and used to phase modulate a transmitted signal. The transmission is interrupted during a number of periods during each pseudo-random sequence which allows returns from targets to be received from the same antenna as is used for transmission during those periods of interruption. Each transmitted pulse, between successive periods of interruption, contains a different selection of successive digits of the code thus increasing the apparent randomness of the transmitted code and making detection more difficult.
Claims20
A noise radar comprising:
- means for repeatedly generating a code comprising a sequence of digits;
- means for transmitting, during each sequence, pulses of energy occupying periods each of which spans at least one digit of the code, with the pulses having a regular pulse repetition frequency which is not an integral multiple of the repetition frequency of said code;
- means for changing said pulse repetition frequency;
- and means for modulating the transmitted energy in accordance with the prevailing output of the generator.
A noise radar comprising:
- generator mans for repeatedly generating a digital code;
- means for transmitting pulses of energy occupying periods each of which spans at least one digit of the code, with said pulses having a regular pulse repetition frequency which is not an integral multiple of the repetition frequency of said digital code;
- means for changing said pulse repetition frequency;
- and means for modulating the transmitted energy in accordance with the coded output of said generator means.
Dependencies are inferred from the claim text.