Sequential circuitry for recreating CW components from chirp-Z pulses

• US 5,384,545 A
• Filed: 11/17/1992
• Issued: 01/24/1995
• Est. Priority Date: 11/17/1992
• Status: Expired due to Fees

• Current Assignee: The United States of America As Represented By The Secretary of Agriculture
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Skudera, William J. Jr.
• Primary Examiner(s): Callahan, Timothy P.
• Assistant Examiner(s): LE, DINH THANH
• Application Number:
  US07/977,354
• Time in Patent Office: 798 Days
• Field of Search: 328/29, 328/56, 328/28, 328/61, 328/14, 328/187, 328/188, 328/189, 324/76.23, 324/76.19
• US Class Current: 327/284
• CPC Class Codes: G01R 23/16 Spectrum analysis; Fourier analysis
• CPC Class Codes: G01S 7/021 Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals

Abstract

Use of inverse transforms regarding chirp-Z analysis is circumvented to ence the chirp-Z output gain. Forward chirp-Z transform pulses relating to individual CW frequency components of interest in a composite signal, are gated to circuitry which replicates those pulses to recreate each such component for the time necessary to accomplish the intended analysis. This circuitry operates at the replicating rate necessary to separate the pulse replications by one-half the width of the pulses.

Claims

1. In a signal analyzer wherein a Chirp-Z forward transform is utilized to compress the individual CW components of the signal into segregated pulses of equal duration, with the pulse of each such component appearing once during each scan of a sweeping local oscillator, the improvement comprising:

sequential circuitry for recreating a selected CW component by repeatedly replicating a forward Chirp-Z transform pulse relating thereto throughout a period of time as necessitated by the intended analysis, with the forward Chirp-Z transform pulse for each CW component selected being gated through a switch to a tapped delay line having the taps thereof separated in time by one-half the Chirp-Z pulse width and one pulse replication is taken from each tap.

2. The analyzer of claim 1 wherein the Chirp-Z pulse replications derived from the tapped delay line are directed as a group to circuitry for duplicating the group of replications in powers of two.

3. The analyzer of claim 2 wherein the duplicating circuitry includes a fixed delay line and summing junction combination for each power of two duplication, the fixed delay line in each such combination having a delay interval equal to that combination'"'"'s particular power of two multiplied by the time duration the group of replications occupies, the first power of two combination receiving the group of replications from the tapped delay line while each power of two combination thereafter receives the group of replications as duplicated by the preceding power of two combination, each power of two combination having the groups of replications directed simultaneously to one input of its summing junction and the input of its fixed delay line, while the output from its fixed delay line is directed to the other input of its summing junction and the duplicated groups of replications pass from the output of its summing junction.