Accession Number : AD0756624

Title :   A CDC-3800 Compass Subroutine for Computing the Power Spectral Density Function of Real Data.

Descriptive Note : Interim rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Brown,Henry A.

Report Date : FEB 1973

Pagination or Media Count : 38

Abstract : Many engineering problems requiring computation of power spectra use real valued input data. The fast Fourier transform (FFT) algorithm. which is used for spectra computations and which is available in subroutine form, performs a Fourier transform of complex valued input data and yields complex valued output data. By taking advantage of the properties of the FFT for real data in and real data out, the number of transformed points can be reduced by a factor of two, thereby reducing computation time and permitting FFT's up to 16384 real points to be computed on the CDC-3800. Further reduction in computation time is realized by programming in COMPASS rather than in FORTRAN. The result is the subroutine PSDF, described herein. Source program listings are included. (Author)

Descriptors :   (*COMPUTER PROGRAMS, *POWER SPECTRA), (*TIME SERIES ANALYSIS, POWER SPECTRA), INTEGRAL TRANSFORMS, FOURIER ANALYSIS, CONTROL SEQUENCES, MEMORY DEVICES, ALGORITHMS

Subject Categories : Theoretical Mathematics
      Computer Programming and Software
      Computer Hardware

Distribution Statement : APPROVED FOR PUBLIC RELEASE