Agilent Technologies N5183A MXG - Manual (Page 226)

216 Agilent N518xA, E8663B, E44x8C, and E82x7D Signal Generators Programming Guide
Creating and Downloading Waveform Files
Creating Waveform Data
Line Code—Interleaving and Byte Swapping for Little Endian Order
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30 char iqbuffer[NUMSAMPLES*4];
for(index=0; index<numsamples; index++)
{
short ivalue = idata[index];
short qvalue = qdata[index];
iqbuffer[index*4] = (ivalue >> 8) & 0xFF;
iqbuffer[index*4+1] = ivalue & 0xFF;
iqbuffer[index*4+2] = (qvalue >> 8) & 0xFF;
iqbuffer[index*4+3] = qvalue & 0xFF;
}
return 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