2.1.22.2.1.19 fft_cosine

1 Description
2 Syntax
3 Parameters
4 Return
5 Examples
6 Remark
7 See Also
8 Header to Include
9 Reference

Description

Performs nFFT-point discrete Fourier Cosine transform. vSig will be padded with zeros if it has less than nFFT points and truncated if it has more.

Syntax

int fft_cosine( int nFFT, vector & vSig )

Parameters

nFFT: [input] number of points to do discrete Fourier Cosine transform.
vSig: [Modify] data for input, and the result data of Fourier cosine for output.

Return

Returns OE_NOERROR for success or error codes for failure.

Examples

Prior to compilation, load fft_utils.c to the workspace by executing the following LabTalk command:

Run.LoadOC("Originlab\fft_utils.c", 16);

To retain fft_utils.c in the workspace for successive sessions, drag and drop the file from the Temporary folder to the System folder.

EX1

#include <fft_utils.h>
void fft_cosine_ex1()
{
    // This example assumes a worksheet is active with three columns, where
    // column 2 has the signal. Column 3 will be filled with Fourier Sine
    // transform result.
    Worksheet wks = Project.ActiveLayer();
    Dataset dsData(wks, 1);
    Dataset dsFCosine(wks, 2);
    // If all datasets are valid, then proceed
    if( dsData && dsFCosine )
    {
        vector vec;
        vec = dsData;
        int nSize = vec.GetSize();
        // Perform sine transform with exact size of signal
        int iRet = fft_cosine(nSize, vec);
        if(0 != iRet )
        {
            printf("Forward FFT returned error: %d\n", iRet );
            return;
        }
        // Store sine transform result
        dsFCosine = vec;
    }
}