% Define parameters of the LFM pulse.
sampleRate = 1e8;               % Define sample rate of baseband signal (Hz)
pulseWidth = 10e-6;             % Define pulse width (seconds)
pulseRepititionInterval = 50e-6;% Define pulse repetition interval (seconds)
bandWidth = 10e6;               % Bandwidth of the pulse (Hz)
IPhase = 0;                     % Initial phase in degrees of IComponent
QPhase = 90;                    % Initial phase in degrees of QComponent

tVector = 0:1/sampleRate:pulseWidth; % Vector to generate ideal pulse
IComponent = chirp(tVector,-bandWidth/2,tVector(end), bandWidth/2,'linear',IPhase);
QComponent = chirp(tVector,-bandWidth/2,tVector(end), bandWidth/2,'linear',QPhase);
IQData = IComponent + 1i*QComponent;

% Normalize amplitude.
scale = max(max(abs(real(IQData))), max(abs(imag(IQData))));
idealPulse = IQData / scale;

% Pad the pulse with zeros for the off cycle of the pulse.
offPulse = 0:1/sampleRate:((pulseRepititionInterval-pulseWidth)/2);
idealSpacedPulse = [offPulse idealPulse offPulse];

figure(1); hold on;
plot((1:length(idealSpacedPulse))/sampleRate, real(idealSpacedPulse),'b')
plot((1:length(idealSpacedPulse))/sampleRate, imag(idealSpacedPulse),'g')
plot((1:length(idealSpacedPulse))/sampleRate, abs(idealSpacedPulse),':r','linewidth',2)
title('One cycle of LFM pulse waveform')
xlabel('Time (s)')
ylabel('Magnitude (V)')
legend('I component','Q component','Envelope')
axis tight; axisLimits = axis; axis([axisLimits(1:2) 1.2*(axisLimits(3:4))])

% Define a filename for the data in the instrument.
ArbFileName = 'MATLAB_WFM';
% Define IP address of the instrument. This will need to be updated to
% execute this code on your instrument.
MXGIPAddress = '172.31.146.123';
% Create a VISA-TCPIP object to connect to the instrument.
signalGeneratorObject = visa('agilent',['TCPIP0::' MXGIPAddress '::inst0::INSTR']);
% Set up the output buffer size to hold at least the number of bytes we are
% transferring. Each point requires 4 bytes (since we are using UINT16
% format to transfer data to the instrument) - 2 bytes for I and 2 bytes
% for Q. An additional overhead for the binblock header is also included in
% the buffer.
signalGeneratorObject.OutputBufferSize = 4*numel(idealSpacedPulse) + 1024;
signalGeneratorObject.ByteOrder = 'bigEndian';
% Set the timeout to ensure the entire waveform is downloaded before a
% timeout occurs.
signalGeneratorObject.Timeout = 10.0;
% Set the terminator character to line feed, or LF (i.e., ASCII code 10).
signalGeneratorObject.EOSCharCode = 'LF';
% Open a connection to the instrument.
fopen(signalGeneratorObject);

% Ensure the waveform is a row vector.
if ~isequal(size(idealSpacedPulse,1),1)
    idealSpacedPulse = reshape(idealSpacedPulse,1,numel(idealSpacedPulse));
end

% Separate out the real and imaginary data in the baseband signal.
wave = [real(idealSpacedPulse);imag(idealSpacedPulse)];
% Transpose the waveform to interleave I & Q data.
wave = wave(:)';

% Scale the waveform. Be sure to prevent division by 0.
tmp = max(abs([max(wave) min(wave)]));
if (tmp == 0)
    tmp = 1;
end

scale = 2^15-1;
scale = scale/tmp;
wave = round(wave * scale);
modval = 2^16;

% Convert from double to unsigned int datatype.
wave = uint16(mod(modval + wave, modval));

% Empty instrument error queue and event registers and reset the instrument.
fprintf(signalGeneratorObject, '*CLS');
fprintf(signalGeneratorObject, '*RST');

% Query the instrument identity and display it.
instrumentInfo = query(signalGeneratorObject, '*IDN?');
fprintf('Instrument identification information: %s', instrumentInfo);

% Turn off instrument before downloading waveform.
fprintf(signalGeneratorObject,':OUTPut:STATe OFF');
fprintf(signalGeneratorObject,':SOURce:RADio:ARB:STATe OFF');
fprintf(signalGeneratorObject,':OUTPut:MODulation:STATe OFF');
% Set the sample rate of the ARB clock to the sample rate of the baseband
% signal.
fprintf(signalGeneratorObject,[':SOURce:RADio:ARB:CLOCk:SRATe ' num2str(sampleRate)]);

% Write the data to the unprotected non-volatile memory of the instrument.
n = size(wave);
fprintf('Starting Download of %d Points...',n(2)/2)
binblockwrite(signalGeneratorObject,wave,'uint16', [':MEM:DATA:UNProtected "WFM1:' ArbFileName '",']);
% The signal generator expects an LF character at the end of the binaryblock.
% By printing a null string with the EOS character set to LF, this byte will
% be sent to the signal generator.
fprintf(signalGeneratorObject,'');

% Wait for instrument to complete download.
% If you see a "Warning: A timeout occurred before the Terminator was reached."
% warning you will need to adjust the signalGeneratorObject.Timeout value
% appropriately.
commandCompleted = query(signalGeneratorObject,'*OPC?');
disp('...done');

% Set the carrier frequency of the upconverted signal.
fprintf(signalGeneratorObject, ':SOURce:FREQuency 3000000000');
% Set the source power to -30dBm.
fprintf(signalGeneratorObject, ':SOURce:POWer -30DBM');
% Select the waveform and initiate generation.
fprintf(signalGeneratorObject,[':SOURce:RADio:ARB:WAV "ARBI:' ArbFileName '"']);
fprintf(signalGeneratorObject,':SOURce:RADio:ARB:STATe ON');
fprintf(signalGeneratorObject,':OUTPut:MODulation:STATe ON');
fprintf(signalGeneratorObject,':OUTPut:STATe ON');

% Read back and display any instrument errors.
instrumentError = query(signalGeneratorObject,'SYST:ERR?');
while isempty(strfind(lower(instrumentError),'no error'))
    fprintf('\tINSTRUMENT ERROR: %s', instrumentError)
    instrumentError = query(signalGeneratorObject,'SYST:ERR?');
end

% Close the connection to the instrument and delete the object.
fclose(signalGeneratorObject); delete(signalGeneratorObject);
clear signalGeneratorObject