Agilent Technologies N5183A MXG, N5181A/82A, E8663B manual 216

Creating and Downloading Waveform Files

Creating Waveform Data

Line Code—Interleaving and Byte Swapping for Little Endian Order

20char iqbuffer[NUMSAMPLES*4];

21for(index=0; index<numsamples; index++)

22{

23short ivalue = idata[index];

24short qvalue = qdata[index];

25 iqbuffer[index*4] = (ivalue >> 8) & 0xFF;

26iqbuffer[index*4+1] = ivalue & 0xFF;

27iqbuffer[index*4+2] = (qvalue >> 8) & 0xFF;

28iqbuffer[index*4+3] = qvalue & 0xFF;

29}

30return 0;

Line	Code Description—Interleaving and Byte Swapping for Little Endian Order
20	Define a character array to store the interleaved I and Q data. The character array makes byte swapping
		easier, since each array location accepts only 8 bits (1 byte). The array size increases by four times to
		accommodate two bytes of I data and two bytes of Q data.
21–29		Create a loop to do the following:
		• Save the current I data array value to a variable.
		NOTE	In rare instances, a compiler may define short as larger than 16 bits. If this condition exists,
			replace short with the appropriate object or label that defines a 16- bit integer.
		• Save the current Q data array value to a variable.
		• Swap the low bytes (bits 0–7) of the data with the high bytes of the data (done for both

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