Abstract: This invention relates to an acousto-optic time-integrating correlator for rocessing broadband Doppler-shifted signals. The present invention uses a conical lens telescope to compensate, in one dimension, for the differences in the absolute values of Doppler shift occurring in broadband signals. A laser light beam is expanded to a sheet beam using a conventional beam expander. The sheet beam is split and redirected using a modified Koster's prism. The two sheet beams are them directed toward a SAW device. The SAW device contains two tilted transducers. The inputs to the SAW device are counterpropagating A Doppler-shifted sheet beam and an undiffracted sheet beam are processed by respective conical lens telescopes. The outputs of the conical lens telescopes are combined with associated unprocessed sheet beams and combined by respective modified Koster's prisms and imaged onto respective two-dimensional photodetectors. The output of one photodetector is subtracted from the other to reduce offsets.

Abstract: An acousto-optic architecture is provided for simultaneously obtaining time integration correlation and power spectrum analysis. A laser beam is expanded and split into first and second beams. The first beam is diffracted by a first acousto-optic Bragg cell, and the second beam is diffracted by a second acousto-optic Bragg cell. The diffracted first beam is split into third and fourth beams, and the diffracted second beam is split into fifth and sixth beams. A first Fourier transform lens system is placed in the path of the third beam, and a first photodiode detector array is placed at the back focal plane of the lens system. A second Fourier transform lens system is placed in the path of the sixth beam, and a second photodiode detector array is placed at the back focal place of the lens system. The fourth and fifth beams are combined and the combined beam is split into seventh and eighth beams.

Abstract: An analog-to-digital converter is disclosed providing high speed operation or high resolution analog signal data. The converter utilizes the repetitive nature of the data by converting a portion of the signal corresponding to the changing component of the data. A smaller number of bits of information is thus converted from analog-to-digital form than is needed to represent the data. In addition to savings in hardware, a significant saving in conversion time is provided. The cancellation of static components of a radar signal moreover provides, within the system, a clutter-free signal.