AN INTERACTIVE FORTRAN PROGRAM FOR CROSS-CORRELATION OF SIGNALS ON A PC WITH CGA GRAPHICS - AN APPLICATION IN MARINE GEOACOUSTICS

Cross-correlation is a method used for comparing two similar signals. CRSCOR is a general purpose program which integrates three tasks: the management, cross-correlation, and graphical display of signals and cross-correlation functions on a PC workstation. Program variables relating to these tasks may be changed through menus thereby precluding the need for recompiling and relinking. Cross-correlation is performed by Fast Fourier Transform with optional use of an 8087 math coprocessor for increasing throughput. The program has a modular architecture with 46 subroutines which simplifies modification of source code if necessary. CRSCOR was developed as part of an overall study of acoustical signals which have interacted with the ocean bottom. From data collected over the continental rise east of Cape Hatteras, tests were conducted on a series of signals from adjacent bottom paths with the grazing angle of each path differing by about 0.3°. Each member of the series was cross-correlated with the first member. Peak values of the cross-correlation function obtained from unfiltered signals were significantly lower than were the peak values from the band-pass filtered (90-200 Hz) versions of these signals indicating that the high-frequency spectrum is more sensitive to path grazing angle than the lower frequency spectrum. © 1990.