<title>Radar And Communication Band Signal Processing Using Time-Integration Processors</title>

Abstract

A new architecture for performing time -integration correlation is described.The correlator uses a surface acoustic wave (SAW) delay line, and features the optical interference of two coherent light beams which have been Bragg-diffracted by SAW's propagating in the line. The time integration is performed by a photodiode array which detects the diffracted light. Time-bandwidth products exceeding 106 (50 MHz times 30 ms) have been achieved. This two -beam SAW acousto -optic time -integrating correlator has been used to detect a number of wideband spread-spectrum signals.It has several attributes which make it particularly well suited for use as a spread-spectrum signal processor.These include linearity of operation, large time aperture over which the correlation can be observed, and the ability to determine the center frequency and bandwidth of the signals.The suitability of this correlator for use as a signal processor in spread-spectrum systems is considered.In addition, a two -dimensional realization of this correlator is proposed for frequency scanning correlation.The use of this frequency scanning correlator as an LPI radar signal processor is discussed.I. AbstractA new architecture for performing time-integration correlation is described. The correlator uses a surface acoustic wave (SAW) delay line, and features the optical interference of two coherent light beams which have been Bragg-diffracted by SAW's propagating in the line. The time integration is performed by a photodiode array which detects the diffracted light. Time-bandwidth products exceeding 10" (50 MHz times 30 ms) have been achieved. This two-beam SAW acousto-optic time-integrating correlator has been used to detect a number of wideband spread-spectrum signals. It has several attributes which make it particularly well suited for use as a spread-spectrum signal processor. These include linearity of operation, large time aperture over which the correlation can be observed, and the ability to determine the center frequency and bandwidth of the signals. The suitability of this correlator for use as a signal processor in spread-spectrum systems is considered. In addition, a two-dimensional realization of this correlator is proposed for frequency scanning correlation. The use of this frequency scanning correlator as an LPI radar signal processor is discussed.

Interferometric Surface-Wave Acousto-Optic Time-Integrating Correlators

“…The output voltage from the photodiode array can be shown to be identical to that for the two-beam correlator as described by equation ( 4 ) . Although intermodulation teras (the interaction of the SAW from the left transducer appearing at the right output diffracted beam and vice-versa) are suppressed by less than the 40 dB achieved with the two-beam architecture, suppression is sufficient for most applications.…”

Analysis of DNA sequences by an optical time-integrating correlator

“…perform the correlation of two signals. The many possible ways to build TICs are well documented in the literature [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] and good review papers are available [15,21,27].…”