Accession Number : AD0659957

Title :   A SYSTEM FOR MEASURING THE FIRST AND SECOND ORDER PROBABILITY DISTRIBUTIONS OF SIGNALS AND NOISE,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : McCoy,Caldwell , Jr. ; Peterson,Herbert L.

Report Date : 11 SEP 1967

Pagination or Media Count : 33

Abstract : A system was designed and developed for use, either in the laboratory or field, to measure the first- and second-order amplitude-probability densities of signals and noise in the area of underwater acoustics. The system consists of a wide-band dc amplifier feeding a sample-and-hold network, followed by an analog-to-digital converter to encode the sampled instantaneous value to an amplitude resolution of ten-bits and sign. These digital codes become the address of a magnetic-core memory, and the value stored in a given address location is a tally for each time that address has been called up. Since the address was directed by the instantaneous amplitude value of a time function, the stored tallies are proportional to the amplitude density of that given time function when plotted out as a histogram. These measured values can be read into a general-purpose digital computer as desired to compute the normalized density function together with moments. This method of code sorting can be applied to other problems of instrumentation, e.g., calibration checks of analog-to-digital converters, stability of analog magnetic tape recorders, and 'drop-out' measurements in analog magnetic tape recording. (Author)

Descriptors :   (*WAVE ANALYZERS, PROBABILITY DENSITY FUNCTIONS), SIGNALS, NOISE, PROBABILITY, MEASUREMENT, UNDERWATER SOUND, COMPUTERS, REAL TIME

Subject Categories : Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE