Agilent - Messignal über GPIB auslesen

Code:
% Specify data from Channel 1

fprintf(visaObj,':WAVEFORM:SOURCE CHAN1'); 

% Specify 1000 points at a time by :WAV:DATA?

fprintf(visaObj,':WAVEFORM:POINTS 1000');

% Get the data back as a WORD (i.e., INT16), other options are ASCII and BYTE

fprintf(visaObj,':WAVEFORM:FORMAT WORD');

% Set the byte order on the instrument as well

fprintf(visaObj,':WAVEFORM:BYTEORDER LSBFirst');

% Get the preamble block

preambleBlock = query(visaObj,':WAVEFORM:PREAMBLE?');

% The preamble block contains all of the current WAVEFORM settings.  

% It is returned in the form <preamble_block><NL> where <preamble_block> is:

%    FORMAT        : int16 - 0 = BYTE, 1 = WORD, 2 = ASCII.

%    TYPE          : int16 - 0 = NORMAL, 1 = PEAK DETECT, 2 = AVERAGE

%    POINTS        : int32 - number of data points transferred.

%    COUNT         : int32 - 1 and is always 1.

%    XINCREMENT    : float64 - time difference between data points.

%    XORIGIN       : float64 - always the first data point in memory.

%    XREFERENCE    : int32 - specifies the data point associated with

%                            x-origin.

%    YINCREMENT    : float32 - voltage diff between data points.

%    YORIGIN       : float32 - value is the voltage at center screen.

%    YREFERENCE    : int32 - specifies the data point where y-origin

%                            occurs.



% Now send commmand to read data

fprintf(visaObj,':WAV:DATA?');

% read back the BINBLOCK with the data in specified format and store it in

% the waveform structure

waveform.RawData = binblockread(visaObj,'uint16');



%% Data processing: Post process the data retreived from the scope

% Extract the X, Y data and plot it 



% Maximum value storable in a INT16

maxVal = 2^16; 



%  split the preambleBlock into individual pieces of info

preambleBlock = regexp(preambleBlock,',','split');



% store all this information into a waveform structure for later use

waveform.Format = str2double(preambleBlock{1});     % This should be 1, since we're specifying INT16 output

waveform.Type = str2double(preambleBlock{2});

waveform.Points = str2double(preambleBlock{3});

waveform.Count = str2double(preambleBlock{4});      % This is always 1

waveform.XIncrement = str2double(preambleBlock{5}); % in seconds

waveform.XOrigin = str2double(preambleBlock{6});    % in seconds

waveform.XReference = str2double(preambleBlock{7});

waveform.YIncrement = str2double(preambleBlock{8}); % V

waveform.YOrigin = str2double(preambleBlock{9});

waveform.YReference = str2double(preambleBlock{10});

waveform.VoltsPerDiv = (maxVal * waveform.YIncrement / 8);      % V

waveform.Offset = ((maxVal/2 - waveform.YReference) * waveform.YIncrement + waveform.YOrigin);         % V

waveform.SecPerDiv = waveform.Points * waveform.XIncrement/10 ; % seconds

waveform.Delay = ((waveform.Points/2 - waveform.XReference) * waveform.XIncrement + waveform.XOrigin); % seconds



% Generate X & Y Data

waveform.XData = (waveform.XIncrement.*(1:length(waveform.RawData))) - waveform.XIncrement;

waveform.YData = (waveform.RawData - waveform.YReference) .* waveform.YIncrement + waveform.YOrigin; 



% Plot it

plot(waveform.XData,waveform.YData);

set(gca,'XTick',(min(waveform.XData):waveform.SecPerDiv:max(waveform.XData)))

xlabel('Time (s)');

ylabel('Volts (V)');

title('Oscilloscope Data');

grid on;