
Accession Number : ADD012650
Title : Method and Apparatus for Generating a Modified P1 Code.
Descriptive Note : Patent,
Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC
Personal Author(s) : Kretschmer,Frank F , Jr ; Lewis,Bernard L
Report Date : 02 Dec 1986
Pagination or Media Count : 7
Abstract : A digital pulse expandercompressor for use impulse compression radars and having the advantage of precompression bandwidth tolerance. The pulse expandercompressor employs a discrete Fourier transform circuit and multistage delay line feeding inputs x(n) to the discrete Fourier transform circuit to generate outputs in accordance with the formula where n is the sequence number of the clock pulse; zN is an even integer corresponding to the number of delay stages plus one and k is the number of the output subpulse from the transform circuit. An arrangement of delay stages differentially delays the output subpulses from the discrete Fourier transform circuit, and a coherent summer adds the real and imaginary parts of the signals from the delay lines. The delay stages delay the subpulse Fk by nN clock pulse intervals where n and k are interrelated by the formulae k=N/2n for n=0,1, ..., and N/2 and k=(3N/2)n for n=N/2+1, N/2+2, ..., N1. The pulse expandercompressor generates a modified, sq N element P1 polyphase code that is tolerant to receiver bandwidth limitation. (Patents)
Descriptors : *CLOCKS, *DISCRETE FOURIER TRANSFORMS, *PULSE SPACING MODULATION, *PATENTS, *RECEIVERS, *RADAR, *PULSE COMPRESSION, PULSES, COHERENCE, SUMMER, DELAY LINES, CIRCUITS, DISCRETE DISTRIBUTION, FORMULAS(MATHEMATICS), INTERACTIONS, DIGITAL SYSTEMS, EXPANSION, NUMBERS, COMPLEX NUMBERS, SEQUENCES, TOLERANCE, BANDWIDTH, LIMITATIONS
Subject Categories : Cybernetics
Active & Passive Radar Detection & Equipment
Distribution Statement : APPROVED FOR PUBLIC RELEASE