Agilent Technologies N5183A MXG - Manual (Page 243)

Agilent N518xA, E8663B, E44x8C, and E82x7D Signal Generators Programming Guide 233
Creating and Downloading Waveform Files
Programming Examples
// 1.) Create Simple IQ Signal *****************************************
// This signal is a single tone on the upper
// side of the carrier and is usually refered to as
// a Single Side Band Suppressed Carrier (SSBSC) signal.
// It is nothing more than a cosine wavefomm in I
// and a sine waveform in Q.
int points = POINTS; // Number of points in the waveform
int cycles = 101; // Determines the frequency offset from the carrier
double Iwave[POINTS]; // I waveform
double Qwave[POINTS]; // Q waveform
short int waveform[2*POINTS]; // Holds interleaved I/Q data
double maxAmp = 0; // Used to Normalize waveform data
double minAmp = 0; // Used to Normalize waveform data
double scale = 1;
char buf; // Used for byte swapping
char *pChar; // Used for byte swapping
bool PC = true; // Set flag as appropriate
double phaseInc = 2.0 * 3.141592654 * cycles / points;
double phase = 0;
int i = 0;
for( i=0; i<points; i++ )
{
phase = i * phaseInc;
Iwave[i] = cos(phase);
Qwave[i] = sin(phase);
}
// 2.) Save waveform in internal format *********************************
// Convert the I and Q data into the internal arb format
// The internal arb format is a single waveform containing interleaved IQ
// data. The I/Q data is signed short integers (16 bits).
// The data has values scaled between +-32767 where
// DAC Value Description
// 32767 Maximum positive value of the DAC
// 0 Zero out of the DAC
// -32767 Maximum negative value of the DAC
// The internal arb expects the data bytes to be in Big Endian format.
// This is opposite of how short integers are saved on a PC (Little Endian).
// For this reason the data bytes are swapped before being saved.