envdet.cpp File Reference

An envelope detection and general purpose FFT routine. More...

Defines

#define SWAP (a,b)
#define NINT (a)

Functions

void four1 (float *data, int nn, int isign)
A complex fourier transform routine.
WORD envdet ( INT32 *data, INT16 npts, INT16 nfactor)
Calculates the envelop of analytic signal.

Detailed Description

An envelope detection and general purpose FFT routine.

$Id: envdet.cpp,v 1.1 1999-03-05 16:31:33-05 ljb Exp ljb $

$Revision: 1.1 $ $Log: envdet.cpp,v $ Revision 1.1 1999-03-05 16:31:33-05 ljb Initial revision

Function Documentation

void four1(float *data, int nn, int isign)

A complex fourier transform routine.

Parameters:: data - points to input data ordered real1, imag1, real2, imag2....; nn - number of complex points. data[0...(2*nn)-1].; isign - indicates forward (+1) or inverse (-1) FFT.

Taken from "Numerical Recipes in C" by Press, Flannery, Teukolsky, & Vetterling, see chapter 12. As discussed in the book, this code assumes that data starts in data[1] and if the first point is actually in data[0] then the pointer needs to be offset by the calling program.

WORD envdet( INT32 *data, INT16 npts, INT16 nfactor)

Calculates the envelop of analytic signal.

Parameters:: data - is the input data record.; npts - is the length of data.; nfactor - is a number used for decimation (downsampling).

An detection routine that calculates the envelop of the analytic signal which is derived from data. On input, data contains RF data. On output, data contains the detected data.

Software written by
Larry Busse of LJB Development
and Bill Glenn, Al Murphy and John Losche of TETRAD Corporation
Documentation generated 3/11/1999