72 lines
1.9 KiB
Mathematica
72 lines
1.9 KiB
Mathematica
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% Matlab Init :noexport:ignore:
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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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%% Initialize ans with org-babel
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ans = 0;
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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_001.mat', 't', 'x1', 'x2');
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sr_on = load('mat/data_002.mat', 't', 'x1', 'x2');
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% Analysis
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% Let's first look at the signal produced by the DAC (figure [[fig:random_signal]]).
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figure;
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hold on;
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plot(sr_on.t, sr_on.x1);
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hold off;
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xlabel('Time [s]'); ylabel('Voltage [V]');
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xlim([0 10]);
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% #+NAME: fig:random_signal
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% #+CAPTION: Random signal produced by the DAC
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% #+RESULTS: fig:random_signal
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% [[file:figs/random_signal.png]]
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% We now look at the difference between the signal directly measured by the ADC and the signal that goes through the slip-ring (figure [[fig:slipring_comp_signals]]).
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figure;
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hold on;
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plot(sr_on.t, sr_on.x1 - sr_on.x2, 'DisplayName', 'Slip-Ring - $\omega = 1rpm$');
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plot(sr_off.t, sr_off.x1 - sr_off.x2,'DisplayName', 'Slip-Ring off');
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hold off;
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xlabel('Time [s]'); ylabel('Voltage [V]');
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xlim([0 10]);
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legend('Location', 'northeast');
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% #+NAME: fig:slipring_comp_signals
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% #+CAPTION: Alteration of the signal when the slip-ring is turning
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% #+RESULTS: fig:slipring_comp_signals
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% [[file:figs/slipring_comp_signals.png]]
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dt = sr_on.t(2) - sr_on.t(1);
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Fs = 1/dt; % [Hz]
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win = hanning(ceil(1*Fs));
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[pxx_on, f] = pwelch(sr_on.x1 - sr_on.x2, win, [], [], Fs);
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[pxx_off, ~] = pwelch(sr_off.x1 - sr_off.x2, win, [], [], Fs);
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figure;
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hold on;
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plot(f, sqrt(pxx_on), 'DisplayName', 'Slip-Ring - $\omega = 1rpm$');
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plot(f, sqrt(pxx_off),'DisplayName', 'Slip-Ring off');
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hold off;
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set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log');
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xlabel('Frequency [Hz]'); ylabel('PSD $\left[\frac{V}{\sqrt{Hz}}\right]$');
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legend('Location', 'northeast');
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xlim([1, 500]); ylim([1e-5, 1e-3])
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