85 lines
2.4 KiB
Matlab
85 lines
2.4 KiB
Matlab
%% Clear Workspace and Close figures
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clear; close all; clc;
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%% Intialize Laplace variable
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s = zpk('s');
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% Load data
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% We load the data of the z axis of two geophones.
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sr_off = load('mat/data_008.mat', 'data'); sr_off = sr_off.data;
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sr_on = load('mat/data_009.mat', 'data'); sr_on = sr_on.data;
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sr_6r = load('mat/data_010.mat', 'data'); sr_6r = sr_6r.data;
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sr_60r = load('mat/data_011.mat', 'data'); sr_60r = sr_60r.data;
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% Time Domain
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% We plot the time domain data for the direct measurement (figure [[fig:sr_direct_time]]) and for the signal going through the slip-ring (figure [[fig:sr_slipring_time]]);
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figure;
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hold on;
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plot(sr_60r(:, 3), sr_60r(:, 1), 'DisplayName', '60rpm');
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plot(sr_6r(:, 3), sr_6r(:, 1), 'DisplayName', '6rpm');
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plot(sr_on(:, 3), sr_on(:, 1), 'DisplayName', 'ON');
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plot(sr_off(:, 3), sr_off(:, 1), 'DisplayName', 'OFF');
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hold off;
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xlabel('Time [s]'); ylabel('Voltage [V]');
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legend('Location', 'northeast');
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% #+NAME: fig:sr_direct_time
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% #+CAPTION: Direct measurement
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% #+RESULTS: fig:sr_direct_time
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% [[file:figs/sr_direct_time.png]]
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figure;
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hold on;
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plot(sr_60r(:, 3), sr_60r(:, 2), 'DisplayName', '60rpm');
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plot(sr_6r(:, 3), sr_6r(:, 2), 'DisplayName', '6rpm');
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plot(sr_on(:, 3), sr_on(:, 2), 'DisplayName', 'ON');
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plot(sr_off(:, 3), sr_off(:, 2), 'DisplayName', 'OFF');
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hold off;
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xlabel('Time [s]'); ylabel('Voltage [V]');
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legend('Location', 'northeast');
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% Frequency Domain
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% We first compute some parameters that will be used for the PSD computation.
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dt = sr_off(2, 3)-sr_off(1, 3);
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Fs = 1/dt; % [Hz]
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win = hanning(ceil(10*Fs));
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% Then we compute the Power Spectral Density using =pwelch= function.
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[pxdir, f] = pwelch(sr_off(:, 1), win, [], [], Fs);
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[pxoff, ~] = pwelch(sr_off(:, 2), win, [], [], Fs);
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[pxon, ~] = pwelch(sr_on(:, 2), win, [], [], Fs);
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[px6r, ~] = pwelch(sr_6r(:, 2), win, [], [], Fs);
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[px60r, ~] = pwelch(sr_60r(:, 2), win, [], [], Fs);
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% And we plot the ASD of the measured signals (figure [[fig:sr_psd_compare]]);
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figure;
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hold on;
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plot(f, sqrt(pxoff), 'DisplayName', 'OFF');
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plot(f, sqrt(pxon), 'DisplayName', 'ON');
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plot(f, sqrt(px6r), 'DisplayName', '6rpm');
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plot(f, sqrt(px60r), 'DisplayName', '60rpm');
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plot(f, sqrt(pxdir), 'k-', 'DisplayName', 'Direct');
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hold off;
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set(gca, 'xscale', 'log');
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set(gca, 'yscale', 'log');
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xlabel('Frequency [Hz]'); ylabel('ASD of the measured Voltage $\left[\frac{V}{\sqrt{Hz}}\right]$')
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legend('Location', 'northeast');
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xlim([0.1, 500]);
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