Precise pulse repetition frequency measuring device and signal sorter

• US 3,940,768 A
• Filed: 01/07/1969
• Issued: 02/24/1976
• Est. Priority Date: 01/07/1969
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Olsen, Robert C., Stahlhut, Frederick O.
• Primary Examiner(s): Hubler, Malcolm F.
• Application Number:
  US04/791,537
• Time in Patent Office: 2,604 Days
• Field of Search: 343/18, 343/17.2
• US Class Current: 342/13
• CPC Class Codes: G01S 7/021 Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals

Abstract

An electronic signal processing device comprised of timing and coincident ting means for utilization between one or more conventional radar receivers and a conventional visual display, multi-gun pulse analyzer to enable an electronic intelligence operator to perform precise real time measurement of the pulse repetition interval (PRI) and its counterpart, pulse repetition frequency (PRF), for any one of a group of radar signals in a multi-signal environment. The device provides an automatic gating loop for separating the received radar video signals into various known preset PRI-PRF bands, an electronic chopping circuit for enabling the device to produce an interleaved, panoramic display of all of the radar video signals within any one of the preset bands on a visual display pulse analyzer, various single-shot multivibrator and gating means for producing necessary synchronizing pulses, and a variable delay unit and pulse generator for selecting a single video signal from the panoramic display for closer examination on an expanded scale of the multi-gun analyzer and for producing a marking pulse which may be positioned by the operator to obtain an indication of the PRI and PRF of the selected signal from a calibrated dial of the variable delay unit.

Claims

1. An electronic signal processing device for performing precise real time measurement of the pulse repetition interval and frequency of pulse radar signals in a multi-signal environment, comprising:

input means for coupling to a radar receiver to receive said pulse radar signals therefrom;

an automatic gating loop coupled to said input means, for receiving said pulse radar signals and separating said signals into discrete bands by pulse repetition interval and frequency;

synchronizing pulse generating means having input means coupled to said automatic gating loop, for producing video synchronizing pulses at its output means in response to control signals from said automatic gating loop;

a first video gating means having first and second input means and an output means, said first input means thereof being coupled to said automatic gating loop for receiving standard video pulses therefrom for each video pulse train within a selected one of said discrete bands, and said second input means thereof being for receiving enabling signals to control the passage of said standard video pulses from said first input means thereof to said output means thereof;

a second video gating means having first and second input means and an output means, said first input means thereof being coupled to said input means for receiving said pulse radar signals from said radar receiver, and said second input means thereof being coupled in parallel with said second input means of said first gating means for receiving said enabling signals to control the passage of said pulse radar signals from said first input means thereof to said output means thereof;

video gating signal generating means having input means coupled in parallel with said input means of said synchronizing pulse generating means to said automatic gating loop for receiving said control signals therefrom, and having output means switchably coupled to said second input means of each of said first and second video gating means, for producing said enabling signals at said output means thereof in response to said control signals from said automatic gating loop;

adjustably linear delay means having input means coupled to said automatic gating loop for receiving said control signals therefrom, having manually adjustable control means for determining the length of delay to be introduced by said delay means between the receipt of said control signals and the production of corresponding output signals, and having output means for providing the delayed said corresponding output signals thereat;

marker pulse generating means having input means coupled to said output means of said adjustable linear delay means for receiving said delayed corresponding output signals therefrom and producing a marker pulse of relatively short duration in response to each such signal, and having output means for providing said marker pulses thereat, said output means thereof being switchably coupled to said second input means of each of said first and second video gating means for providing said marker pulses as enabling signals thereto; and

summing amplifier means having a first input means coupled to said output means of said synchronizing pulse generating means for receiving said video synchronizing pulses therefrom, a second input means coupled to said output means of said marker pulse generating means for receiving said marker pulses therefrom, and a third input means switchably coupled to the respective output means of said first and second video gating means for alternatively receiving said standard video pulses from said first video gating means and said unknown pulse radar signals from said second video gating means, and having output means for providing thereat a composite signal comprised of said synchronizing pulses, said video pulses, and said marker pulses for coupling to a pulse analyzing display means.

2. An electronic signal processing device for performing precise real time measurement of the pulse repetition interval and frequency of pulse radar signals in a multi-signal environment as set forth in claim 1 wherein said input means for coupling to a radar receiver comprises:

a video amplifier for amplifying said pulse radar signals received from said radar receiver; and

an automatic threshold control means having input means coupled to said video amplifier for receiving the amplified said pulse radar signals therefrom and having output means for providing thereat a pulse of predetermined amplitude and width for each incoming pulse radar signal having an amplitude above a preset level.

3. An electronic signal processing device for performing precise real time measurement of the pulse repetition interval and frequency of pulse radar signals in a multi-signal environment as set forth in claim 1 wherein said automatic gating loop comprises:

a coincidence gating means having a plurality of inputs and an output, one of said inputs being coupled to said input means for coupling to a radar receiver to receive said pulse radar signals therefrom;

a timing reference means for providing selected fixed delays, including a countdown divider means driven by a stable oscillator means, the output of said divider means being coupled to at least one of said inputs of said coincidence gating means to cause said coincidence gating means to be maintained in a blocking condition throughout each of said selected fixed delays;

a standard pulse generating means having input means coupled to said output of said coincidence gating means for receiving coincidence signals therefrom, and having output means for providing thereat a pulse signal of predetermined width and amplitude in response to each of said coincidence signals received, said output means being coupled to said countdown divider means to initiate each of said fixed delays and to said first input means of said first video gating means for providing said standard video pulses thereto; and

an electronic chopper means switchably coupled to said input means of said standard pulse generating means for causing said standard pulse generating means to produce output pulses independent of said coincidence signals from said coincidence gating means.

4. An electronic signal processing device for performing precise real time measurement of the pulse repetition interval and frequency of pulse radar signals in a multi-signal environment as set forth in claim 1 wherein:

said synchronizing pulse generating means is comprised of a monostable multivibrator, for providing an output pulse of high amplitude and short duration;

said video gating signal generating means is comprised of a monostable multivibrator, for providing an output pulse of medium amplitude and long duration; and

said marker pulse generating means is comprised of a monostable multivibrator, for providing an output pulse of medium amplitude and short duration.

5. An electronic signal processing device for performing precise real time measurement of the pulse repetition interval and frequency of pulse radar signals in a multi-signal environment as set forth in claim 4 wherein said automatic gating loop comprises:

a coincidence gating means having a plurality of inputs and an output, one of said inputs being coupled to said input means for coupling to a radar receiver to receive said pulse radar signals therefrom;

a timing reference means for providing selected fixed delays, including a countdown divider means driven by a stable oscillator means, the output of said divider means being coupled to at least one of said inputs of said coincidence gating means to cause said coincidence gating means to be maintained in a blocking condition throughout each of said selected fixed delays;

a standard pulse generating means having input means coupled to said output of said coincidence gating means for receiving coincidence signals therefrom, and having output means for providing thereat a pulse signal of predetermined width and amplitude in response to each of said coincidence signals received, said output means being coupled to said countdown divider means to initiate each of said fixed delays and to said first input means of said first video gating means for providing said standard video pulses thereto; and

an electronic chopper means switchably coupled to said input means of said standard pulse generating means for causing said standard pulse generating means to produce output pulses independent of said coincidence signals from said coincidence gating means.