Richard A Mosher

US Patent:

43152619, Feb 9, 1982

Filed:

Jun 3, 1980

Appl. No.:

6/156102

Inventors:

Richard K. Mosher - Sudbury MA

Assignee:

Controlonics Corporation - Littleton MA

International Classification:

G01S 728
G01S 736

US Classification:

343 18E

Abstract:

A sensitive radar signal detector is provided which is operative to reliably detect low level radar radiation characteristic of scattered radiation of very short duration and unknown frequency. Received radar signals which are mixed with a swept frequency signal are passed through to a narrow band FM descriminator, the output of which is amplified by a unidirectional amplifier. The output of the amplifier, present when a signal is received, is utilized to momentarily slow the frequency swept local oscillator resulting in a time expansion of the characteristic S-shaped descriminator output signal. This results in the generation of a negative-going error signal between the two time expanded halves of the S-shaped descriminator response. The error signal when amplified produces a significant voltage spike which ensures reliable detection, to permit the detection of a single radar pulse with a reduced false alarm rate.