Accession Number : ADD011839

Title :   P2 Polyphase Code Expander-Compressor.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Kretschmer,F F

Report Date : 18 Jun 1985

Pagination or Media Count : 5

Abstract : A pulse expansion and compression system, especially useful for radar ranging, comprising a pulse coder for expanding an input pulse and a pulse compressor of the matched-filter type. The coder consists of a plurality of delay stages into which the input pulse is fed, a discrete Fourier transform (DFT) circuit to which the output signals of the delay stages are fed by way of respective phase weights and for which every frequency port is phase-shifted prior to entry to a time-dispersion-means (TDM) comprising an arrangement of delay stages for differently delaying the output signals from the DFT. The TDM output is fed to a phase modulator and then to the transmitter. The echo signals are conjugated, time-inverted, and passed through the same DFT as the input pulse signal by way of the phase weights. The outputs of the DFT are then phase-shifted at every frequency port and passed through the TDM, but this time in time-inverted order. The outputs of the TDM are fed through an envelope detector to provide a cross-correlated facsimile of the original input pulse. (Author)

Descriptors :   *PATENTS, *RADAR PULSES, *PULSE COMPRESSION, *PULSE CODE MODULATION, PHASE MODULATION, MATCHED FILTERS, FAST FOURIER TRANSFORMS, RANGE FINDING, DISCRETE FOURIER TRANSFORMS, PHASE SHIFT CIRCUITS, RADAR, EXPANSION, WEIGHT, ENVELOPE(SPACE), MODULATORS, FREQUENCY, OUTPUT, ECHOES, DELAY, SIGNALS, PULSES, DETECTORS, INPUT, CODERS, COMPRESSION

Subject Categories : Electrical and Electronic Equipment
      Active & Passive Radar Detection & Equipment
      Electromagnetic Pulses

Distribution Statement : APPROVED FOR PUBLIC RELEASE