Accession Number : ADD015087

Title :   High Pulse Repetition Frequency Radar Early Warning Receiver.

Descriptive Note : Patent, Filed 4 Oct 89, patented 23 Apr 91,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Huntley, William P ; Swanick, David J

Report Date : 23 Apr 1991

Pagination or Media Count : 5

Abstract : A ten db coupler receives an RF input signal and transmits an attenuated signal through a wideband/narrow band select switch to an RF amplifier. The signal is next processed through an RF amplitude detector. A comparator then receivers the signal and generates a pulse in response to signals exceeding a predetermined threshold. A pulse stretcher then eliminates excessive pulses due to noise or other signal oscillations that exceeded the comparator's threshold. A circuit comprising a retriggerable monostable and an OR gate determine if the pulses received exceed a pulse repetition frequency threshold. A ripple counter than eliminates unwanted signals by resetting if a predetermined number is not reached in a specified time. A unique audio signal is then generated if the desired signal is detected. The output signal is audible even though the input signal is of a frequency above the normal hearing threshold. Also a visual signal is provided by a light emitting diode.

Descriptors :   AMPLITUDE, BROADBAND, COMPARATORS, DETECTORS, HEARING, INPUT, LIGHT EMITTING DIODES, NARROWBAND, OSCILLATION, OUTPUT, PULSE RATE, PULSE SPACING MODULATION, RADIOFREQUENCY, RADIOFREQUENCY AMPLIFIERS, RESPONSE, SIGNALS, THRESHOLD EFFECTS, THRESHOLDS(PHYSIOLOGY), VISUAL SIGNALS

Subject Categories : Active & Passive Radar Detection & Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE