D/A correlator structures

A number of high-speed correlator structures appropriate for the processing of signals in sonar and communication systems are described. Various combinations of shift registers, exclusive/ORs, charge-coupled devices, and acoustic surface-wave devices can be used to implement, in modular form, M-bit-vs-binary, M-bit-vs-N-bit, or analog-vs-N-bit correlators and matched filters. Programmability of both channels provides a very flexible type of matched filter whose configuration can be organized by computer control. Various modes of operation of the correlator structures appropriate for signal processing applications, including the programmable matched filter mode and the alternate-shift cross-correlator mode, are discussed along with associated oscilloscope photographs of experimental results using laboratory prototype equipment.