Add PicoVNA108_S_Parameter_Example.m to show how to use PicoVNA 108 in MATLAB

Author: neil-hamilton

examples/PicoVNA108_S_Parameter_Example.m

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+%% PicoVNA108 S-Parameter Example
+%
+% This is an example of setting up the connection with the Pico Technology
+% PicoVNA Vector Network Analyzer, loading calibration data, making measurements and collecting
+% the log magnitude data for S11, S12, S21 and S22 parameters.
+%
+% To run this example session, type the name of the file,
+% |PicoVNA_S_Parameter_Example|, in the MATLAB Command Window.
+%
+% The file, |PicoVNA108_S_Parameter_Example.m| must be on your MATLAB Path. For
+% additional information on setting your MATLAB path, see
+% <matlab:doc('addpath') addpath>.
+%
+% Additionally you must have the |.cal| file for your device in the current
+% folder.
+%
+% *Example:*
+%   PicoVNA108_S-Parameter_Example;
+%
+% *Description:*
+% Demonstrates how to connect to the VNA108, load in a calibration, make
+% measurements and collect data for S11, S12, S21 and S22 parameters.  The
+% S-parameters are plotted onto auto-scaled plots.  The measurement and
+% data collection is looped until the user stops the process.
+%
+% *Copyright:* © 2017-2020 Pico Technology Ltd. See LICENSE file for terms.
+
+%% Clear workspace, command window and close figures
+
+clear;
+clc;
+close all;
+
+%% Connect to VNA
+
+picoVNACOMObj = connectVNA108;
+
+%% Load Calibration
+% Load a calibration and settings file.
+% This needs to be generated and saved using the PicoVNA2 software.
+
+% Replace DefCal.cal with the correct calibration for your device, 'Pico TD
+% demo with limits [Serial#].cal'.
+picoVNACOMObj.LoadCal('?');
+
+%%
+% This needs to be generated and saved using the PicoVNA 2 software.
+%
+% Replace |DefCal.cal| with the correct calibration for your device, |Pico TD
+% demo with limits [Serial#].cal|.
+picoVNACOMObj.LoadCal('DefCal.cal');
+
+%% Stop button for exiting loop
+% Create a stop button for exiting rapid block capture and for displaying
+% the data in.
+[stopFig.f, stopFig.h] = stopButtonVNA(0, 50, 1350,1000);   
+
+flag = 1; % Use flag variable to indicate if stop button has been clicked (0)
+setappdata(gcf, 'run', flag);
+
+%% Capture and plot data
+
+n = 0; % Number of Loops
+go = 1; % While loop condition (1 = run, 0 = stop)
+
+while go == 1
+    
+    % Instruct VNA do make a sweep measurement
+    picoVNACOMObj.Measure('Raw');
+    
+    % Get Log magnitude data for all S-Parameters 
+    [s11.freq, s11.logmagDataPoints] = getBlockDataVNA(picoVNACOMObj,'S11','logmag');
+    [s22.freq, s22.logmagDataPoints] = getBlockDataVNA(picoVNACOMObj,'S22','logmag'); 
+    [s12.freq, s12.logmagDataPoints] = getBlockDataVNA(picoVNACOMObj,'S12','logmag');
+    [s21.freq, s21.logmagDataPoints] = getBlockDataVNA(picoVNACOMObj,'S21','logmag');
+    
+    % Get values for y-axes limits
+    maxS11c = max(s11.logmagDataPoints);
+    
+    if n == 0
+        maxS11 = maxS11c;
+    end
+    
+    if maxS11c > maxS11
+        maxS11 = maxS11c;
+    end
+    
+    minS11c = min(s11.logmagDataPoints);
+    
+    if n == 0
+        minS11 = minS11c;
+    end
+    
+    if minS11c < minS11
+        minS11 = minS11c;
+    end
+    
+    maxS22c = max(s22.logmagDataPoints);
+    
+    if n == 0
+        maxS22 = maxS22c;
+    end
+    
+    if maxS22c > maxS22
+        maxS22 = maxS22c;
+    end
+    
+    minS22c = min(s22.logmagDataPoints);
+    
+    if n == 0
+        minS22 = minS22c;
+    end
+    
+    if minS22c < minS22
+        minS22 = minS22c;
+    end
+    
+    maxS12c = max(s12.logmagDataPoints);
+    
+    if n == 0
+        maxS12 = maxS12c;
+    end
+    
+    if maxS12c > maxS12
+        maxS12 = maxS12c;
+    end
+    
+    minS12c = min(s12.logmagDataPoints);
+    
+    if n == 0
+        minS12 = minS12c;
+    end
+    
+    if minS12c < minS12
+        minS12 = minS12c;
+    end
+    
+    maxS21c = max(s21.logmagDataPoints);
+    
+    if n == 0
+        maxS21 = maxS21c;
+    end
+    
+    if maxS21c > maxS21
+        maxS21 = maxS21c;
+    end
+    
+    minS21c = min(s21.logmagDataPoints);
+    
+    if n == 0
+        minS21 = minS21c;
+    end
+    
+    if minS21c < minS21
+        minS21 = minS21c;
+    end
+    
+    
+    % Plot Data for all S-parameters
+    subplot(2,2,1);
+    plot(s11.freq, s11.logmagDataPoints);
+    xlabel('Frequency (Hz)');
+    ylabel('Magnitude (dB)');
+    ylim([minS11 maxS11]);
+    title('S11')
+    
+    subplot(2,2,2);
+    plot(s12.freq, s12.logmagDataPoints);
+    xlabel('Frequency (Hz)');
+    ylabel('Magnitude (dB)');
+    ylim([minS12 maxS12]);
+    title('S12');
+    
+    subplot(2,2,3);
+    plot(s21.freq, s21.logmagDataPoints);
+    xlabel('Frequency (Hz)');
+    ylabel('Magnitude (dB)');
+    ylim([minS21 maxS21]);
+    title('S21');
+    
+    subplot(2,2,4);
+    plot(s22.freq, s22.logmagDataPoints);
+    xlabel('Frequency (Hz)');
+    ylabel('Magnitude (dB)');
+    ylim([minS22 maxS22]);
+    title('S22');
+    
+    drawnow
+    
+    n = n+1 % Current Loop Number
+       
+    % Check if stop button has been pressed
+    flag = getappdata(gcf, 'run');
+    if flag == 0
+        go = 0;
+    end
+    clear maxS11c minS11c maxS12c minS12c maxS21c minS21c maxS22c minS22c
+end
+%% Disconnect VNA
+
+disconnectVNA(picoVNACOMObj)
+
+% Tidy workspace
+clear ans flag go maxS11 minS11 maxS12 minS12 maxS21 minS21 maxS22 minS22 picoVNACOMObj