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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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
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