Agilent Technologies E8663B, N5181A/82A, N5183A MXG manual Code Algorithm, Create I and Q data

Creating and Downloading Waveform Files

Creating Waveform Data

Code Algorithm

This section uses code from the C++ programming example “Importing, Byte Swapping, Interleaving, and Downloading I and Q Data—Big and Little Endian Order” on page 249 to demonstrate how to create and scale waveform data.

There are three steps in the process of creating an I/Q waveform:

1.Create the I and Q data.

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

3.Interleave the I and Q data to make an I/Q file, and swap the byte order for little- endian platforms.

For information on downloading I/Q waveform data to a signal generator, refer to “Commands and File Paths for Downloading and Extracting Waveform Data” on page 206 and “Downloading Waveform Data” on page 218.

1. Create I and Q data.

The following lines of code create scaled I and Q data for a sine wave. The I data consists of one period of a sine wave and the Q data consists of one period of a cosine wave.

Line Code—Create I and Q data

1const int NUMSAMPLES=500;

2main(int argc, char* argv[]);

3{

4short idata[NUMSAMPLES];

5short qdata[NUMSAMPLES];

6int numsamples = NUMSAMPLES;

7for(int index=0; index<numsamples; index++);

8{

9idata[index]=23000 * sin((2*3.14*index)/numsamples);

10qdata[index]=23000 * cos((2*3.14*index)/numsamples);

11}

Line Code Description—Create I and Q data

1Define the number of waveform points. Note that the maximum number of waveform points that you can set is based on the amount of available memory in the signal generator. For more information on signal generator memory, refer to “Waveform Memory” on page 198.

2Define the main function in C++.

4Create an array to hold the generated I values. The array length equals the number of the waveform points. Note that we define the array as type short, which represents a 16- bit signed integer in most C++ compilers.

5

Create an array to hold the generated Q values (signed 16- bit integers).

6

Define and set a temporary variable, which is used to calculate the I and Q values.

Agilent N518xA, E8663B, E44x8C, and E82x7D Signal Generators Programming Guide 213