Agilent Technologies N5181A/82A, N5183A MXG, E8663B Save the I/Q data to a text file to review

Creating and Downloading Waveform Files

Creating Waveform Data

2. Save the I/Q data to a text file to review.

The following lines of code export the I and Q data to a text file for validation. After exporting the data, open the file using Microsoft Excel or a similar spreadsheet program, and verify that the I and Q data are correct.

Line Code Description—Saving the I/Q Data to a Text File

12char *ofile = "c:\\temp\\iq.txt";

13FILE *outfile = fopen(ofile, "w");

14if (outfile==NULL) perror ("Error opening file to write");

15for(index=0; index<numsamples; index++)

16{

17fprintf(outfile, "%d, %d\n", idata[index], qdata[index]);

18}

19fclose(outfile);

Line Code Description—Saving the I/Q Data to a Text File

12Set the absolute path of a text file to a character variable. In this example, iq.txt is the file name and *ofile is the variable name.

For the file path, some operating systems may not use the drive prefix (‘c:’ in this example), or may require only a single forward slash (/), or both ("/temp/iq.txt")

13

Open the text file in write format.

14

If the text file does not open, print an error message.

15–18

Create a loop that prints the array of generated I and Q data samples to the text file.

19

Close the text file.

3. Interleave the I and Q data, and byte swap if using little endian order.

This step has two sets of code:

•Interleaving and byte swapping I and Q data for little endian order

•Interleaving I and Q data for big endian order

For more information on byte order, see “Little Endian and Big Endian (Byte Order)” on page 186.

Agilent N518xA, E8663B, E44x8C, and E82x7D Signal Generators Programming Guide 215