Agilent Technologies N5183A MXG, N5181A/82A, E8663B manual 256

Creating and Downloading Waveform Files

Programming Examples

phaseInc = 2*pi*cycles/points; phase = phaseInc * [0:points-1];

Iwave = cos(phase);

Qwave = 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.

%Interleave the IQ data

waveform(1:2:2*points) = Iwave; waveform(2:2:2*points) = Qwave; %[Iwave;Qwave];

%waveform = waveform(:)’;

% Normalize the data between +-1
waveform =	waveform / max(abs(waveform)); % Watch out for divide by zero.
% Scale to	use full range of the DAC
waveform =	round(waveform * 32767);	% Data is now effectively signed short integer values
% waveform	= round(waveform * (32767	/ max(abs(waveform))));	% More efficient than previous two
steps!

%PRESERVE THE BIT PATTERN but convert the waveform to

%unsigned short integers so the bytes can be swapped.

%Note: Can’t swap the bytes of signed short integers in MatLab. waveform = uint16(mod(65536 + waveform,65536)); %

%If on a PC swap the bytes to Big Endian

if strcmp( computer, ‘PCWIN’ )

waveform = bitor(bitshift(waveform,-8),bitshift(waveform,8));

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