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Add data analysis of 03/05

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Thomas Dehaeze 2019-05-06 10:28:35 +02:00
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* TODO [#B] Find the documentation of the amplifier to know the order of the filters
* TODO [#A] Shake a little bit the geophones to see if we have better measurements on X and Y axis
* Measurements
| Filename | Description |
|--------------+-------------|
| data_001.mat | Z axis |
| data_002.mat | East |
| data_003.mat | North |

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"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"> <html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head> <head>
<!-- 2019-05-03 ven. 14:39 --> <!-- 2019-05-06 lun. 10:28 -->
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" /> <meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" /> <meta name="viewport" content="width=device-width, initial-scale=1" />
<title>Effect of the rotation of the Slip-Ring</title> <title>Measurements</title>
<meta name="generator" content="Org mode" /> <meta name="generator" content="Org mode" />
<meta name="author" content="Thomas Dehaeze" /> <meta name="author" content="Thomas Dehaeze" />
<style type="text/css"> <style type="text/css">
@ -249,23 +249,71 @@ for the JavaScript code in this tag.
</head> </head>
<body> <body>
<div id="content"> <div id="content">
<h1 class="title">Effect of the rotation of the Slip-Ring</h1> <h1 class="title">Measurements</h1>
<div id="table-of-contents"> <div id="table-of-contents">
<h2>Table of Contents</h2> <h2>Table of Contents</h2>
<div id="text-table-of-contents"> <div id="text-table-of-contents">
<ul> <ul>
<li><a href="#orgfad781f">1. Measurement Description</a></li> <li><a href="#org157e9c7">1. Effect of the rotation of the Slip-Ring</a>
<li><a href="#org15aab25">2. Load data</a></li> <ul>
<li><a href="#orgf84fddf">3. Analysis</a></li> <li><a href="#orgb6072a4">1.1. Measurement Description</a></li>
<li><a href="#org072e1d4">4. Conclusion</a></li> <li><a href="#orgecd569a">1.2. Load data</a></li>
<li><a href="#org3836a40">1.3. Analysis</a></li>
<li><a href="#orgc938992">1.4. Conclusion</a></li>
</ul>
</li>
<li><a href="#org64d6a43">2. Measure of the noise of the Voltage Amplifier</a>
<ul>
<li><a href="#org3cb5cbc">2.1. Measurement Description</a></li>
<li><a href="#org9a88df6">2.2. Load data</a></li>
<li><a href="#org9594967">2.3. Time Domain</a></li>
<li><a href="#orgb6ac137">2.4. Frequency Domain</a></li>
<li><a href="#org2bfd545">2.5. Conclusion</a></li>
</ul>
</li>
<li><a href="#orgd197020">3. Measure of the noise induced by the Slip-Ring</a>
<ul>
<li><a href="#org6be0417">3.1. Measurement Description</a></li>
<li><a href="#org894df46">3.2. Load data</a></li>
<li><a href="#orgfb5cd93">3.3. Time Domain</a></li>
<li><a href="#orge70b1cd">3.4. Frequency Domain</a></li>
<li><a href="#org1067ac0">3.5. Conclusion</a></li>
</ul>
</li>
<li><a href="#orga6075e6">4. Measure of the noise induced by the slip ring when using a geophone</a>
<ul>
<li><a href="#orga3d1fca">4.1. Measurement Description</a></li>
<li><a href="#org874ef1d">4.2. Load data</a></li>
<li><a href="#org3656f2f">4.3. Time Domain</a></li>
<li><a href="#orgf3c9d01">4.4. Frequency Domain</a></li>
<li><a href="#orgbee8de0">4.5. Conclusion</a></li>
</ul>
</li>
<li><a href="#org22d6637">5. Measure of the influence of the AC/DC option on the voltage amplifiers</a>
<ul>
<li><a href="#org947094c">5.1. Measurement Description</a></li>
<li><a href="#orgd3f6cb3">5.2. Load data</a></li>
<li><a href="#org85a856a">5.3. Time Domain</a></li>
<li><a href="#org18d9eca">5.4. Frequency Domain</a></li>
<li><a href="#org21d0038">5.5. Conclusion</a></li>
</ul>
</li>
</ul> </ul>
</div> </div>
</div> </div>
<div id="outline-container-orgfad781f" class="outline-2"> <div id="outline-container-org157e9c7" class="outline-2">
<h2 id="orgfad781f"><span class="section-number-2">1</span> Measurement Description</h2> <h2 id="org157e9c7"><span class="section-number-2">1</span> Effect of the rotation of the Slip-Ring</h2>
<div class="outline-text-2" id="text-1"> <div class="outline-text-2" id="text-1">
<p> <p>
The data and matlab files are accessible <a href="data/meas_effect_sr.zip">here</a>.
</p>
</div>
<div id="outline-container-orgb6072a4" class="outline-3">
<h3 id="orgb6072a4"><span class="section-number-3">1.1</span> Measurement Description</h3>
<div class="outline-text-3" id="text-1-1">
<p>
Random Signal is generated by one DAC of the SpeedGoat. Random Signal is generated by one DAC of the SpeedGoat.
</p> </p>
@ -352,9 +400,9 @@ Here, the rotation speed of the Slip-Ring is set to 1rpm.
</div> </div>
</div> </div>
<div id="outline-container-org15aab25" class="outline-2"> <div id="outline-container-orgecd569a" class="outline-3">
<h2 id="org15aab25"><span class="section-number-2">2</span> Load data</h2> <h3 id="orgecd569a"><span class="section-number-3">1.2</span> Load data</h3>
<div class="outline-text-2" id="text-2"> <div class="outline-text-3" id="text-1-2">
<p> <p>
We load the data of the z axis of two geophones. We load the data of the z axis of two geophones.
</p> </p>
@ -366,11 +414,11 @@ sr_on = load<span class="org-rainbow-delimiters-depth-1">(</span><span class="o
</div> </div>
</div> </div>
<div id="outline-container-orgf84fddf" class="outline-2"> <div id="outline-container-org3836a40" class="outline-3">
<h2 id="orgf84fddf"><span class="section-number-2">3</span> Analysis</h2> <h3 id="org3836a40"><span class="section-number-3">1.3</span> Analysis</h3>
<div class="outline-text-2" id="text-3"> <div class="outline-text-3" id="text-1-3">
<p> <p>
Let's first look at the signal produced by the DAC (figure <a href="#org36eec0a">1</a>). Let's first look at the signal produced by the DAC (figure <a href="#org9e05a67">1</a>).
</p> </p>
<div class="org-src-container"> <div class="org-src-container">
@ -384,14 +432,14 @@ xlim<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-rainbo
</div> </div>
<div id="org36eec0a" class="figure"> <div id="org9e05a67" class="figure">
<p><img src="figs/random_signal.png" alt="random_signal.png" /> <p><img src="figs/random_signal.png" alt="random_signal.png" />
</p> </p>
<p><span class="figure-number">Figure 1: </span>Random signal produced by the DAC</p> <p><span class="figure-number">Figure 1: </span>Random signal produced by the DAC</p>
</div> </div>
<p> <p>
We now look at the difference between the signal directly measured by the ADC and the signal that goes through the slip-ring (figure <a href="#orga6ca37c">2</a>). We now look at the difference between the signal directly measured by the ADC and the signal that goes through the slip-ring (figure <a href="#orgbaee8bd">2</a>).
</p> </p>
<div class="org-src-container"> <div class="org-src-container">
@ -407,7 +455,7 @@ legend<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-stri
</div> </div>
<div id="orga6ca37c" class="figure"> <div id="orgbaee8bd" class="figure">
<p><img src="figs/slipring_comp_signals.png" alt="slipring_comp_signals.png" /> <p><img src="figs/slipring_comp_signals.png" alt="slipring_comp_signals.png" />
</p> </p>
<p><span class="figure-number">Figure 2: </span>Alteration of the signal when the slip-ring is turning</p> <p><span class="figure-number">Figure 2: </span>Alteration of the signal when the slip-ring is turning</p>
@ -428,7 +476,7 @@ win = hanning<span class="org-rainbow-delimiters-depth-1">(</span>ceil<span clas
</div> </div>
<div id="orgc50d568" class="figure"> <div id="orgd69e796" class="figure">
<p><img src="figs/psd_noise.png" alt="psd_noise.png" /> <p><img src="figs/psd_noise.png" alt="psd_noise.png" />
</p> </p>
<p><span class="figure-number">Figure 3: </span>ASD of the measured noise</p> <p><span class="figure-number">Figure 3: </span>ASD of the measured noise</p>
@ -436,9 +484,9 @@ win = hanning<span class="org-rainbow-delimiters-depth-1">(</span>ceil<span clas
</div> </div>
</div> </div>
<div id="outline-container-org072e1d4" class="outline-2"> <div id="outline-container-orgc938992" class="outline-3">
<h2 id="org072e1d4"><span class="section-number-2">4</span> Conclusion</h2> <h3 id="orgc938992"><span class="section-number-3">1.4</span> Conclusion</h3>
<div class="outline-text-2" id="text-4"> <div class="outline-text-3" id="text-1-4">
<div class="note"> <div class="note">
<p> <p>
<b>Remaining questions</b>: <b>Remaining questions</b>:
@ -448,13 +496,647 @@ win = hanning<span class="org-rainbow-delimiters-depth-1">(</span>ceil<span clas
<li>Use higher rotation speed and measure for longer periods (to have multiple revolutions) ?</li> <li>Use higher rotation speed and measure for longer periods (to have multiple revolutions) ?</li>
</ul> </ul>
</div>
</div>
</div>
</div>
<div id="outline-container-org64d6a43" class="outline-2">
<h2 id="org64d6a43"><span class="section-number-2">2</span> Measure of the noise of the Voltage Amplifier</h2>
<div class="outline-text-2" id="text-2">
<p>
The data and matlab files are accessible <a href="data/meas_volt_amp.zip">here</a>.
</p>
</div>
<div id="outline-container-org3cb5cbc" class="outline-3">
<h3 id="org3cb5cbc"><span class="section-number-3">2.1</span> Measurement Description</h3>
<div class="outline-text-3" id="text-2-1">
<p>
<b>Goal</b>:
</p>
<ul class="org-ul">
<li>Determine the Voltage Amplifier noise</li>
</ul>
<p>
<b>Setup</b>:
</p>
<ul class="org-ul">
<li>The two inputs (differential) of the voltage amplifier are shunted with 50Ohms</li>
<li>The AC/DC option of the Voltage amplifier is on AC</li>
<li>The low pass filter is set to 1hHz</li>
<li>We measure the output of the voltage amplifier with a 16bits ADC of the Speedgoat</li>
</ul>
<p>
<b>Measurements</b>:
</p>
<ul class="org-ul">
<li><code>data_003</code>: Ampli OFF</li>
<li><code>data_004</code>: Ampli ON set to 20dB</li>
<li><code>data_005</code>: Ampli ON set to 40dB</li>
<li><code>data_006</code>: Ampli ON set to 60dB</li>
</ul>
</div>
</div>
<div id="outline-container-org9a88df6" class="outline-3">
<h3 id="org9a88df6"><span class="section-number-3">2.2</span> Load data</h3>
<div class="outline-text-3" id="text-2-2">
<div class="org-src-container">
<pre class="src src-matlab">amp_off = load<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'mat/data_003.mat', 'data'</span><span class="org-rainbow-delimiters-depth-1">)</span>; amp_off = amp_off.data<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-type">:</span>, <span class="org-rainbow-delimiters-depth-2">[</span><span class="org-highlight-numbers-number">1</span>,<span class="org-highlight-numbers-number">3</span><span class="org-rainbow-delimiters-depth-2">]</span><span class="org-rainbow-delimiters-depth-1">)</span>;
amp_20d = load<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'mat/data_004.mat', 'data'</span><span class="org-rainbow-delimiters-depth-1">)</span>; amp_20d = amp_20d.data<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-type">:</span>, <span class="org-rainbow-delimiters-depth-2">[</span><span class="org-highlight-numbers-number">1</span>,<span class="org-highlight-numbers-number">3</span><span class="org-rainbow-delimiters-depth-2">]</span><span class="org-rainbow-delimiters-depth-1">)</span>;
amp_40d = load<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'mat/data_005.mat', 'data'</span><span class="org-rainbow-delimiters-depth-1">)</span>; amp_40d = amp_40d.data<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-type">:</span>, <span class="org-rainbow-delimiters-depth-2">[</span><span class="org-highlight-numbers-number">1</span>,<span class="org-highlight-numbers-number">3</span><span class="org-rainbow-delimiters-depth-2">]</span><span class="org-rainbow-delimiters-depth-1">)</span>;
amp_60d = load<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'mat/data_006.mat', 'data'</span><span class="org-rainbow-delimiters-depth-1">)</span>; amp_60d = amp_60d.data<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-type">:</span>, <span class="org-rainbow-delimiters-depth-2">[</span><span class="org-highlight-numbers-number">1</span>,<span class="org-highlight-numbers-number">3</span><span class="org-rainbow-delimiters-depth-2">]</span><span class="org-rainbow-delimiters-depth-1">)</span>;
</pre>
</div>
</div>
</div>
<div id="outline-container-org9594967" class="outline-3">
<h3 id="org9594967"><span class="section-number-3">2.3</span> Time Domain</h3>
<div class="outline-text-3" id="text-2-3">
<p>
The time domain signals are shown on figure <a href="#orgcfdcbce">4</a>.
</p>
<div id="orgcfdcbce" class="figure">
<p><img src="figs/ampli_noise_time.png" alt="ampli_noise_time.png" />
</p>
<p><span class="figure-number">Figure 4: </span>Output of the amplifier</p>
</div>
</div>
</div>
<div id="outline-container-orgb6ac137" class="outline-3">
<h3 id="orgb6ac137"><span class="section-number-3">2.4</span> Frequency Domain</h3>
<div class="outline-text-3" id="text-2-4">
<p>
We first compute some parameters that will be used for the PSD computation.
</p>
<div class="org-src-container">
<pre class="src src-matlab">dt = amp_off<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlight-numbers-number">2</span>, <span class="org-highlight-numbers-number">2</span><span class="org-rainbow-delimiters-depth-1">)</span><span class="org-type">-</span>amp_off<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlight-numbers-number">1</span>, <span class="org-highlight-numbers-number">2</span><span class="org-rainbow-delimiters-depth-1">)</span>;
Fs = <span class="org-highlight-numbers-number">1</span><span class="org-type">/</span>dt; <span class="org-comment">% [Hz]</span>
win = hanning<span class="org-rainbow-delimiters-depth-1">(</span>ceil<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-highlight-numbers-number">10</span><span class="org-type">*</span>Fs<span class="org-rainbow-delimiters-depth-2">)</span><span class="org-rainbow-delimiters-depth-1">)</span>;
</pre>
</div>
<p>
Then we compute the Power Spectral Density using <code>pwelch</code> function.
</p>
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-rainbow-delimiters-depth-1">[</span>pxoff, f<span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>amp_off<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>,<span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-rainbow-delimiters-depth-1">[</span>px20d, <span class="org-type">~</span><span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>amp_20d<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>,<span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-rainbow-delimiters-depth-1">[</span>px40d, <span class="org-type">~</span><span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>amp_40d<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>,<span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-rainbow-delimiters-depth-1">[</span>px60d, <span class="org-type">~</span><span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>amp_60d<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>,<span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
</pre>
</div>
<p>
We compute the theoretical ADC noise.
</p>
<div class="org-src-container">
<pre class="src src-matlab">q = <span class="org-highlight-numbers-number">20</span><span class="org-type">/</span><span class="org-highlight-numbers-number">2</span><span class="org-type">^</span><span class="org-highlight-numbers-number">16</span>; <span class="org-comment">% quantization</span>
Sq = q<span class="org-type">^</span><span class="org-highlight-numbers-number">2</span><span class="org-type">/</span><span class="org-highlight-numbers-number">12</span><span class="org-type">/</span><span class="org-highlight-numbers-number">1000</span>; <span class="org-comment">% PSD of the ADC noise</span>
</pre>
</div>
<p>
Finally, the ASD is shown on figure <a href="#orgf5bb8f5">5</a>.
</p>
<div id="orgf5bb8f5" class="figure">
<p><img src="figs/ampli_noise_psd.png" alt="ampli_noise_psd.png" />
</p>
<p><span class="figure-number">Figure 5: </span>Amplitude Spectral Density of the measured voltage at the output of the voltage amplifier</p>
</div>
</div>
</div>
<div id="outline-container-org2bfd545" class="outline-3">
<h3 id="org2bfd545"><span class="section-number-3">2.5</span> Conclusion</h3>
<div class="outline-text-3" id="text-2-5">
<div class="important">
<p>
Noise induced by the voltage amplifiers is not a limiting factor.
</p>
</div>
</div>
</div>
</div>
<div id="outline-container-orgd197020" class="outline-2">
<h2 id="orgd197020"><span class="section-number-2">3</span> Measure of the noise induced by the Slip-Ring</h2>
<div class="outline-text-2" id="text-3">
<p>
The data and matlab files are accessible <a href="data/meas_slip_ring.zip">here</a>.
</p>
</div>
<div id="outline-container-org6be0417" class="outline-3">
<h3 id="org6be0417"><span class="section-number-3">3.1</span> Measurement Description</h3>
<div class="outline-text-3" id="text-3-1">
<p>
<b>Goal</b>:
</p>
<ul class="org-ul">
<li>Determine the noise induced by the slip-ring</li>
</ul>
<p>
<b>Setup</b>:
</p>
<ul class="org-ul">
<li>0V is generated by the DAC of the Speedgoat</li>
<li>Using a T, one part goes directly to the ADC</li>
<li>The other part goes to the slip-ring 2 times and then to the ADC</li>
<li>The parameters of the Voltage Amplifier are: 80dB, AC, 1kHz</li>
<li>Every stage of the station is OFF</li>
</ul>
<p>
First column: Direct measure
Second column: Slip-ring measure
</p>
<p>
<b>Measurements</b>:
</p>
<ul class="org-ul">
<li><code>data_008</code>: Slip-Ring OFF</li>
<li><code>data_009</code>: Slip-Ring ON</li>
<li><code>data_010</code>: Slip-Ring ON and omega=6rpm</li>
<li><code>data_011</code>: Slip-Ring ON and omega=60rpm</li>
</ul>
</div>
</div>
<div id="outline-container-org894df46" class="outline-3">
<h3 id="org894df46"><span class="section-number-3">3.2</span> Load data</h3>
<div class="outline-text-3" id="text-3-2">
<p>
We load the data of the z axis of two geophones.
</p>
<div class="org-src-container">
<pre class="src src-matlab">sr_off = load<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'mat/data_008.mat', 'data'</span><span class="org-rainbow-delimiters-depth-1">)</span>; sr_off = sr_off.data;
sr_on = load<span class="org-rainbow-delimiters-depth-1">(</span>'mat<span class="org-type">/</span>data_009.mat', <span class="org-string">'data'</span><span class="org-rainbow-delimiters-depth-1">)</span>; sr_on = sr_on.data;
sr_6r = load<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'mat/data_010.mat', 'data'</span><span class="org-rainbow-delimiters-depth-1">)</span>; sr_6r = sr_6r.data;
sr_60r = load<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'mat/data_011.mat', 'data'</span><span class="org-rainbow-delimiters-depth-1">)</span>; sr_60r = sr_60r.data;
</pre>
</div>
</div>
</div>
<div id="outline-container-orgfb5cd93" class="outline-3">
<h3 id="orgfb5cd93"><span class="section-number-3">3.3</span> Time Domain</h3>
<div class="outline-text-3" id="text-3-3">
<p>
We plot the time domain data for the direct measurement (figure <a href="#orgcff48af">6</a>) and for the signal going through the slip-ring (figure <a href="#orgfbc52db">7</a>);
</p>
<div id="orgcff48af" class="figure">
<p><img src="figs/sr_direct_time.png" alt="sr_direct_time.png" />
</p>
<p><span class="figure-number">Figure 6: </span>Direct measurement</p>
</div>
<div id="orgfbc52db" class="figure">
<p><img src="figs/sr_slipring_time.png" alt="sr_slipring_time.png" />
</p>
<p><span class="figure-number">Figure 7: </span>Measurement of the signal going through the Slip-Ring</p>
</div>
</div>
</div>
<div id="outline-container-orge70b1cd" class="outline-3">
<h3 id="orge70b1cd"><span class="section-number-3">3.4</span> Frequency Domain</h3>
<div class="outline-text-3" id="text-3-4">
<p>
We first compute some parameters that will be used for the PSD computation.
</p>
<div class="org-src-container">
<pre class="src src-matlab">dt = sr_off<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlight-numbers-number">2</span>, <span class="org-highlight-numbers-number">3</span><span class="org-rainbow-delimiters-depth-1">)</span><span class="org-type">-</span>sr_off<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlight-numbers-number">1</span>, <span class="org-highlight-numbers-number">3</span><span class="org-rainbow-delimiters-depth-1">)</span>;
Fs = <span class="org-highlight-numbers-number">1</span><span class="org-type">/</span>dt; <span class="org-comment">% [Hz]</span>
win = hanning<span class="org-rainbow-delimiters-depth-1">(</span>ceil<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-highlight-numbers-number">10</span><span class="org-type">*</span>Fs<span class="org-rainbow-delimiters-depth-2">)</span><span class="org-rainbow-delimiters-depth-1">)</span>;
</pre>
</div>
<p>
Then we compute the Power Spectral Density using <code>pwelch</code> function.
</p>
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-rainbow-delimiters-depth-1">[</span>pxdir, f<span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>sr_off<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-rainbow-delimiters-depth-1">[</span>pxoff, <span class="org-type">~</span><span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>sr_off<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">2</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-rainbow-delimiters-depth-1">[</span>pxon, <span class="org-type">~</span><span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>sr_on<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">2</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-rainbow-delimiters-depth-1">[</span>px6r, <span class="org-type">~</span><span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>sr_6r<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">2</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-rainbow-delimiters-depth-1">[</span>px60r, <span class="org-type">~</span><span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>sr_60r<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">2</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
</pre>
</div>
<p>
And we plot the ASD of the measured signals (figure <a href="#org16c9932">8</a>);
</p>
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-type">figure</span>;
hold on;
plot<span class="org-rainbow-delimiters-depth-1">(</span>f, sqrt<span class="org-rainbow-delimiters-depth-2">(</span>pxoff<span class="org-rainbow-delimiters-depth-2">)</span>, <span class="org-string">'DisplayName', 'OFF'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
plot<span class="org-rainbow-delimiters-depth-1">(</span>f, sqrt<span class="org-rainbow-delimiters-depth-2">(</span>pxon<span class="org-rainbow-delimiters-depth-2">)</span>, <span class="org-string">'DisplayName', 'ON'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
plot<span class="org-rainbow-delimiters-depth-1">(</span>f, sqrt<span class="org-rainbow-delimiters-depth-2">(</span>px6r<span class="org-rainbow-delimiters-depth-2">)</span>, 'DisplayName', '<span class="org-highlight-numbers-number">6rpm</span>'<span class="org-rainbow-delimiters-depth-1">)</span>;
plot<span class="org-rainbow-delimiters-depth-1">(</span>f, sqrt<span class="org-rainbow-delimiters-depth-2">(</span>px60r<span class="org-rainbow-delimiters-depth-2">)</span>, 'DisplayName', '<span class="org-highlight-numbers-number">60rpm</span>'<span class="org-rainbow-delimiters-depth-1">)</span>;
plot<span class="org-rainbow-delimiters-depth-1">(</span>f, sqrt<span class="org-rainbow-delimiters-depth-2">(</span>pxdir<span class="org-rainbow-delimiters-depth-2">)</span>, <span class="org-string">'k-', 'DisplayName', 'Direct'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
hold off;
<span class="org-type">set</span><span class="org-rainbow-delimiters-depth-1">(</span><span class="org-variable-name">gca</span>, <span class="org-string">'xscale', 'log'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-type">set</span><span class="org-rainbow-delimiters-depth-1">(</span><span class="org-variable-name">gca</span>, <span class="org-string">'yscale', 'log'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
xlabel<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'Frequency </span><span class="org-string"><span class="org-rainbow-delimiters-depth-2">[</span></span><span class="org-string">Hz</span><span class="org-string"><span class="org-rainbow-delimiters-depth-2">]</span></span><span class="org-string">'</span><span class="org-string"><span class="org-rainbow-delimiters-depth-1">)</span></span><span class="org-string">; ylabel</span><span class="org-string"><span class="org-rainbow-delimiters-depth-1">(</span></span><span class="org-string">'</span>ASD of the measured Voltage $<span class="org-type">\</span>left<span class="org-rainbow-delimiters-depth-2">[</span><span class="org-type">\</span>frac<span class="org-rainbow-delimiters-depth-3">{</span>V<span class="org-rainbow-delimiters-depth-3">}{</span><span class="org-type">\</span>sqrt<span class="org-rainbow-delimiters-depth-4">{</span>Hz<span class="org-rainbow-delimiters-depth-4">}</span><span class="org-rainbow-delimiters-depth-3">}</span><span class="org-type">\</span>right<span class="org-rainbow-delimiters-depth-2">]</span>$'<span class="org-rainbow-delimiters-depth-1">)</span>
legend<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'Location', 'northeast'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
xlim<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-rainbow-delimiters-depth-2">[</span><span class="org-highlight-numbers-number">0</span>.<span class="org-highlight-numbers-number">1</span>, <span class="org-highlight-numbers-number">500</span><span class="org-rainbow-delimiters-depth-2">]</span><span class="org-rainbow-delimiters-depth-1">)</span>;
</pre>
</div>
<div id="org16c9932" class="figure">
<p><img src="figs/sr_psd_compare.png" alt="sr_psd_compare.png" />
</p>
<p><span class="figure-number">Figure 8: </span>Comparison of the ASD of the measured signals when the slip-ring is ON, OFF and turning</p>
</div>
</div>
</div>
<div id="outline-container-org1067ac0" class="outline-3">
<h3 id="org1067ac0"><span class="section-number-3">3.5</span> Conclusion</h3>
<div class="outline-text-3" id="text-3-5">
<div class="important">
<p>
</p>
</div>
</div>
</div>
</div>
<div id="outline-container-orga6075e6" class="outline-2">
<h2 id="orga6075e6"><span class="section-number-2">4</span> Measure of the noise induced by the slip ring when using a geophone</h2>
<div class="outline-text-2" id="text-4">
<p>
The data and matlab files are accessible <a href="data/meas_sr_geophone.zip">here</a>.
</p>
</div>
<div id="outline-container-orga3d1fca" class="outline-3">
<h3 id="orga3d1fca"><span class="section-number-3">4.1</span> Measurement Description</h3>
<div class="outline-text-3" id="text-4-1">
<p>
<b>Goal</b>:
</p>
<ul class="org-ul">
<li>Determine if the noise induced by the slip-ring is a limiting factor when measuring the signal coming from a geophone</li>
</ul>
<p>
<b>Setup</b>:
</p>
<ul class="org-ul">
<li>The geophone is located at the sample location</li>
<li>The two Voltage amplifiers have the following settings:
<ul class="org-ul">
<li>AC</li>
<li>60dB</li>
<li>1kHz</li>
</ul></li>
<li>The signal from the geophone is split into two using a T-BNC:
<ul class="org-ul">
<li>One part goes directly to the voltage amplifier and then to the ADC.</li>
<li>The other part goes to the slip-ring=&gt;voltage amplifier=&gt;ADC.</li>
</ul></li>
</ul>
<p>
First column: Direct measure
Second column: Slip-ring measure
</p>
<p>
<b>Measurements</b>:
</p>
<ul class="org-ul">
<li><code>data_012</code>: Slip-Ring OFF</li>
<li><code>data_013</code>: Slip-Ring ON</li>
</ul>
</div>
</div>
<div id="outline-container-org874ef1d" class="outline-3">
<h3 id="org874ef1d"><span class="section-number-3">4.2</span> Load data</h3>
<div class="outline-text-3" id="text-4-2">
<p>
We load the data of the z axis of two geophones.
</p>
<div class="org-src-container">
<pre class="src src-matlab">sr_off = load<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'mat/data_012.mat', 'data'</span><span class="org-rainbow-delimiters-depth-1">)</span>; sr_off = sr_off.data;
sr_on = load<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'mat/data_013.mat', 'data'</span><span class="org-rainbow-delimiters-depth-1">)</span>; sr_on = sr_on.data;
</pre>
</div>
</div>
</div>
<div id="outline-container-org3656f2f" class="outline-3">
<h3 id="org3656f2f"><span class="section-number-3">4.3</span> Time Domain</h3>
<div class="outline-text-3" id="text-4-3">
<p>
We compare the signal when the Slip-Ring is OFF (figure <a href="#orge33756c">9</a>) and when it is ON (figure <a href="#orgb36b65d">10</a>).
</p>
<div id="orge33756c" class="figure">
<p><img src="figs/sr_geophone_time_off.png" alt="sr_geophone_time_off.png" />
</p>
<p><span class="figure-number">Figure 9: </span>Comparison of the time domain signals when the slip-ring is OFF</p>
</div>
<div id="orgb36b65d" class="figure">
<p><img src="figs/sr_geophone_time_on.png" alt="sr_geophone_time_on.png" />
</p>
<p><span class="figure-number">Figure 10: </span>Comparison of the time domain signals when the slip-ring is ON</p>
</div>
</div>
</div>
<div id="outline-container-orgf3c9d01" class="outline-3">
<h3 id="orgf3c9d01"><span class="section-number-3">4.4</span> Frequency Domain</h3>
<div class="outline-text-3" id="text-4-4">
<p>
We first compute some parameters that will be used for the PSD computation.
</p>
<div class="org-src-container">
<pre class="src src-matlab">dt = sr_off<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlight-numbers-number">2</span>, <span class="org-highlight-numbers-number">3</span><span class="org-rainbow-delimiters-depth-1">)</span><span class="org-type">-</span>sr_off<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlight-numbers-number">1</span>, <span class="org-highlight-numbers-number">3</span><span class="org-rainbow-delimiters-depth-1">)</span>;
Fs = <span class="org-highlight-numbers-number">1</span><span class="org-type">/</span>dt; <span class="org-comment">% [Hz]</span>
win = hanning<span class="org-rainbow-delimiters-depth-1">(</span>ceil<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-highlight-numbers-number">10</span><span class="org-type">*</span>Fs<span class="org-rainbow-delimiters-depth-2">)</span><span class="org-rainbow-delimiters-depth-1">)</span>;
</pre>
</div>
<p>
Then we compute the Power Spectral Density using <code>pwelch</code> function.
</p>
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-comment">% Direct measure</span>
<span class="org-rainbow-delimiters-depth-1">[</span>pxdoff, <span class="org-type">~</span><span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>sr_off<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-rainbow-delimiters-depth-1">[</span>pxdon, <span class="org-type">~</span><span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>sr_on<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-comment">% Slip-Ring measure</span>
<span class="org-rainbow-delimiters-depth-1">[</span>pxsroff, f<span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>sr_off<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">2</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-rainbow-delimiters-depth-1">[</span>pxsron, <span class="org-type">~</span><span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>sr_on<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">2</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
</pre>
</div>
<p>
Finally, we compare the Amplitude Spectral Density of the signals (figure [[]]);
</p>
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-type">figure</span>;
hold on;
plot<span class="org-rainbow-delimiters-depth-1">(</span>f, sqrt<span class="org-rainbow-delimiters-depth-2">(</span>pxdoff<span class="org-rainbow-delimiters-depth-2">)</span>, <span class="org-string">'DisplayName', 'Direct - OFF'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
plot<span class="org-rainbow-delimiters-depth-1">(</span>f, sqrt<span class="org-rainbow-delimiters-depth-2">(</span>pxsroff<span class="org-rainbow-delimiters-depth-2">)</span>, <span class="org-string">'DisplayName', 'Slip-Ring - OFF'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
plot<span class="org-rainbow-delimiters-depth-1">(</span>f, sqrt<span class="org-rainbow-delimiters-depth-2">(</span>pxdon<span class="org-rainbow-delimiters-depth-2">)</span>, <span class="org-string">'DisplayName', 'Direct - ON'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
plot<span class="org-rainbow-delimiters-depth-1">(</span>f, sqrt<span class="org-rainbow-delimiters-depth-2">(</span>pxsron<span class="org-rainbow-delimiters-depth-2">)</span>, <span class="org-string">'DisplayName', 'Slip-Ring - ON'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
hold off;
<span class="org-type">set</span><span class="org-rainbow-delimiters-depth-1">(</span><span class="org-variable-name">gca</span>, <span class="org-string">'xscale', 'log'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-type">set</span><span class="org-rainbow-delimiters-depth-1">(</span><span class="org-variable-name">gca</span>, <span class="org-string">'yscale', 'log'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
xlabel<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'Frequency </span><span class="org-string"><span class="org-rainbow-delimiters-depth-2">[</span></span><span class="org-string">Hz</span><span class="org-string"><span class="org-rainbow-delimiters-depth-2">]</span></span><span class="org-string">'</span><span class="org-string"><span class="org-rainbow-delimiters-depth-1">)</span></span><span class="org-string">; ylabel</span><span class="org-string"><span class="org-rainbow-delimiters-depth-1">(</span></span><span class="org-string">'</span>ASD of the measured Voltage $<span class="org-type">\</span>left<span class="org-rainbow-delimiters-depth-2">[</span><span class="org-type">\</span>frac<span class="org-rainbow-delimiters-depth-3">{</span>V<span class="org-rainbow-delimiters-depth-3">}{</span><span class="org-type">\</span>sqrt<span class="org-rainbow-delimiters-depth-4">{</span>Hz<span class="org-rainbow-delimiters-depth-4">}</span><span class="org-rainbow-delimiters-depth-3">}</span><span class="org-type">\</span>right<span class="org-rainbow-delimiters-depth-2">]</span>$'<span class="org-rainbow-delimiters-depth-1">)</span>
legend<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'Location', 'northeast'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
xlim<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-rainbow-delimiters-depth-2">[</span><span class="org-highlight-numbers-number">0</span>.<span class="org-highlight-numbers-number">1</span>, <span class="org-highlight-numbers-number">500</span><span class="org-rainbow-delimiters-depth-2">]</span><span class="org-rainbow-delimiters-depth-1">)</span>;
</pre>
</div>
<div id="org574455b" class="figure">
<p><img src="figs/sr_geophone_asd.png" alt="sr_geophone_asd.png" />
</p>
<p><span class="figure-number">Figure 11: </span>Comparison of the Amplitude Spectral Sensity</p>
</div>
<div id="org7c2558c" class="figure">
<p><img src="figs/sr_geophone_asd_zoom.png" alt="sr_geophone_asd_zoom.png" />
</p>
<p><span class="figure-number">Figure 12: </span>Comparison of the Amplitude Spectral Sensity - Zoom</p>
</div>
</div>
</div>
<div id="outline-container-orgbee8de0" class="outline-3">
<h3 id="orgbee8de0"><span class="section-number-3">4.5</span> Conclusion</h3>
<div class="outline-text-3" id="text-4-5">
<div class="important">
<ul class="org-ul">
<li>When the slip-ring is OFF, it does not add any noise to the measurement</li>
<li>When the slip-ring is ON, it adds significant noise to the signal</li>
</ul>
</div>
</div>
</div>
</div>
<div id="outline-container-org22d6637" class="outline-2">
<h2 id="org22d6637"><span class="section-number-2">5</span> Measure of the influence of the AC/DC option on the voltage amplifiers</h2>
<div class="outline-text-2" id="text-5">
<p>
The data and matlab files are accessible <a href="data/meas_noise_ac_dc.zip">here</a>.
</p>
</div>
<div id="outline-container-org947094c" class="outline-3">
<h3 id="org947094c"><span class="section-number-3">5.1</span> Measurement Description</h3>
<div class="outline-text-3" id="text-5-1">
<p>
<b>Goal</b>:
</p>
<ul class="org-ul">
<li>Measure the influence of the high-pass filter option of the voltage amplifiers</li>
</ul>
<p>
<b>Setup</b>:
</p>
<ul class="org-ul">
<li>One geophone is located on the marble.</li>
<li>It's signal goes to two voltage amplifiers with a gain of 60dB.</li>
<li>One voltage amplifier is on the AC option, the other is on the DC option.</li>
</ul>
<p>
<b>Measurements</b>:
First measurement (<code>mat/data_014.mat</code> file):
</p>
<table border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<colgroup>
<col class="org-right" />
<col class="org-left" />
</colgroup>
<thead>
<tr>
<th scope="col" class="org-right">Column</th>
<th scope="col" class="org-left">Signal</th>
</tr>
</thead>
<tbody>
<tr>
<td class="org-right">1</td>
<td class="org-left">Amplifier 1 with AC option</td>
</tr>
<tr>
<td class="org-right">2</td>
<td class="org-left">Amplifier 2 with DC option</td>
</tr>
<tr>
<td class="org-right">3</td>
<td class="org-left">Time</td>
</tr>
</tbody>
</table>
<p>
Second measurement (<code>mat/data_015.mat</code> file):
</p>
<table border="2" cellspacing="0" cellpadding="6" rules="groups" frame="hsides">
<colgroup>
<col class="org-right" />
<col class="org-left" />
</colgroup>
<thead>
<tr>
<th scope="col" class="org-right">Column</th>
<th scope="col" class="org-left">Signal</th>
</tr>
</thead>
<tbody>
<tr>
<td class="org-right">1</td>
<td class="org-left">Amplifier 1 with DC option</td>
</tr>
<tr>
<td class="org-right">2</td>
<td class="org-left">Amplifier 2 with AC option</td>
</tr>
<tr>
<td class="org-right">3</td>
<td class="org-left">Time</td>
</tr>
</tbody>
</table>
</div>
</div>
<div id="outline-container-orgd3f6cb3" class="outline-3">
<h3 id="orgd3f6cb3"><span class="section-number-3">5.2</span> Load data</h3>
<div class="outline-text-3" id="text-5-2">
<p>
We load the data of the z axis of two geophones.
</p>
<div class="org-src-container">
<pre class="src src-matlab">meas14 = load<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'mat/data_014.mat', 'data'</span><span class="org-rainbow-delimiters-depth-1">)</span>; meas14 = meas14.data;
meas15 = load<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-string">'mat/data_015.mat', 'data'</span><span class="org-rainbow-delimiters-depth-1">)</span>; meas15 = meas15.data;
</pre>
</div>
</div>
</div>
<div id="outline-container-org85a856a" class="outline-3">
<h3 id="org85a856a"><span class="section-number-3">5.3</span> Time Domain</h3>
<div class="outline-text-3" id="text-5-3">
<p>
The signals are shown on figure <a href="#org5f9a2bc">13</a>.
</p>
<div id="org5f9a2bc" class="figure">
<p><img src="figs/ac_dc_option_time.png" alt="ac_dc_option_time.png" />
</p>
<p><span class="figure-number">Figure 13: </span>Comparison of the signals going through the Voltage amplifiers</p>
</div>
</div>
</div>
<div id="outline-container-org18d9eca" class="outline-3">
<h3 id="org18d9eca"><span class="section-number-3">5.4</span> Frequency Domain</h3>
<div class="outline-text-3" id="text-5-4">
<p>
We first compute some parameters that will be used for the PSD computation.
</p>
<div class="org-src-container">
<pre class="src src-matlab">dt = meas14<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlight-numbers-number">2</span>, <span class="org-highlight-numbers-number">3</span><span class="org-rainbow-delimiters-depth-1">)</span><span class="org-type">-</span>meas14<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-highlight-numbers-number">1</span>, <span class="org-highlight-numbers-number">3</span><span class="org-rainbow-delimiters-depth-1">)</span>;
Fs = <span class="org-highlight-numbers-number">1</span><span class="org-type">/</span>dt; <span class="org-comment">% [Hz]</span>
win = hanning<span class="org-rainbow-delimiters-depth-1">(</span>ceil<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-highlight-numbers-number">10</span><span class="org-type">*</span>Fs<span class="org-rainbow-delimiters-depth-2">)</span><span class="org-rainbow-delimiters-depth-1">)</span>;
</pre>
</div>
<p>
Then we compute the Power Spectral Density using <code>pwelch</code> function.
</p>
<div class="org-src-container">
<pre class="src src-matlab"><span class="org-rainbow-delimiters-depth-1">[</span>pxamp1ac, f<span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>meas14<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-rainbow-delimiters-depth-1">[</span>pxamp2dc, <span class="org-type">~</span><span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>meas14<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">2</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-rainbow-delimiters-depth-1">[</span>pxamp1dc, <span class="org-type">~</span><span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>meas15<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
<span class="org-rainbow-delimiters-depth-1">[</span>pxamp2ac, <span class="org-type">~</span><span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>meas15<span class="org-rainbow-delimiters-depth-2">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">2</span><span class="org-rainbow-delimiters-depth-2">)</span>, win, <span class="org-rainbow-delimiters-depth-2">[]</span>, <span class="org-rainbow-delimiters-depth-2">[]</span>, Fs<span class="org-rainbow-delimiters-depth-1">)</span>;
</pre>
</div>
<p>
The ASD of the signals are compare on figure <a href="#org86218d3">14</a>.
</p>
<div id="org86218d3" class="figure">
<p><img src="figs/ac_dc_option_asd.png" alt="ac_dc_option_asd.png" />
</p>
<p><span class="figure-number">Figure 14: </span>Amplitude Spectral Density of the measured signals</p>
</div>
</div>
</div>
<div id="outline-container-org21d0038" class="outline-3">
<h3 id="org21d0038"><span class="section-number-3">5.5</span> Conclusion</h3>
<div class="outline-text-3" id="text-5-5">
<div class="important">
<p>
</p>
</div>
</div> </div>
</div> </div>
</div> </div>
</div> </div>
<div id="postamble" class="status"> <div id="postamble" class="status">
<p class="author">Author: Thomas Dehaeze</p> <p class="author">Author: Thomas Dehaeze</p>
<p class="date">Created: 2019-05-03 ven. 14:39</p> <p class="date">Created: 2019-05-06 lun. 10:28</p>
<p class="validation"><a href="http://validator.w3.org/check?uri=referer">Validate</a></p> <p class="validation"><a href="http://validator.w3.org/check?uri=referer">Validate</a></p>
</div> </div>
</body> </body>

607
slip-ring-test/index.org
View File

@ -1,4 +1,4 @@
#+TITLE:Effect of the rotation of the Slip-Ring #+TITLE: Measurements
:DRAWER: :DRAWER:
#+STARTUP: overview #+STARTUP: overview
@ -18,7 +18,22 @@
#+PROPERTY: header-args:matlab+ :output-dir figs #+PROPERTY: header-args:matlab+ :output-dir figs
:END: :END:
* Measurement Description * Effect of the rotation of the Slip-Ring
:PROPERTIES:
:header-args:matlab+: :tangle meas_effect_sr.m
:header-args:matlab+: :comments org :mkdirp yes
:END:
#+begin_src bash :exports none :results none
zip data/meas_effect_sr \
mat/data_001.mat \
mat/data_002.mat \
meas_effect_sr.m
#+end_src
The data and matlab files are accessible [[file:data/meas_effect_sr.zip][here]].
** Measurement Description
Random Signal is generated by one DAC of the SpeedGoat. Random Signal is generated by one DAC of the SpeedGoat.
The signal going out of the DAC is split into two: The signal going out of the DAC is split into two:
@ -42,19 +57,19 @@ The goal is to determine is the signal is altered when the spindle is rotating.
Here, the rotation speed of the Slip-Ring is set to 1rpm. Here, the rotation speed of the Slip-Ring is set to 1rpm.
* Matlab Init :noexport:ignore: ** Matlab Init :noexport:ignore:
#+begin_src matlab :exports none :results silent :noweb yes #+begin_src matlab :exports none :results silent :noweb yes
<<matlab-init>> <<matlab-init>>
#+end_src #+end_src
* Load data ** Load data
We load the data of the z axis of two geophones. We load the data of the z axis of two geophones.
#+begin_src matlab :results none #+begin_src matlab :results none
sr_off = load('mat/data_001.mat', 't', 'x1', 'x2'); sr_off = load('mat/data_001.mat', 't', 'x1', 'x2');
sr_on = load('mat/data_002.mat', 't', 'x1', 'x2'); sr_on = load('mat/data_002.mat', 't', 'x1', 'x2');
#+end_src #+end_src
* Analysis ** Analysis
Let's first look at the signal produced by the DAC (figure [[fig:random_signal]]). Let's first look at the signal produced by the DAC (figure [[fig:random_signal]]).
#+begin_src matlab :results none #+begin_src matlab :results none
@ -122,7 +137,7 @@ We now look at the difference between the signal directly measured by the ADC an
set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log'); set(gca, 'xscale', 'log'); set(gca, 'yscale', 'log');
xlabel('Frequency [Hz]'); ylabel('PSD $\left[\frac{V}{\sqrt{Hz}}\right]$'); xlabel('Frequency [Hz]'); ylabel('PSD $\left[\frac{V}{\sqrt{Hz}}\right]$');
legend('Location', 'northeast'); legend('Location', 'northeast');
xlim([1, 500]); xlim([1, 500]); ylim([1e-5, 1e-3])
#+end_src #+end_src
#+NAME: fig:psd_noise #+NAME: fig:psd_noise
@ -136,9 +151,587 @@ We now look at the difference between the signal directly measured by the ADC an
#+RESULTS: fig:psd_noise #+RESULTS: fig:psd_noise
[[file:figs/psd_noise.png]] [[file:figs/psd_noise.png]]
* Conclusion ** Conclusion
#+begin_note #+begin_note
*Remaining questions*: *Remaining questions*:
- Should the measurement be redone using voltage amplifiers? - Should the measurement be redone using voltage amplifiers?
- Use higher rotation speed and measure for longer periods (to have multiple revolutions) ? - Use higher rotation speed and measure for longer periods (to have multiple revolutions) ?
#+end_note #+end_note
* Measure of the noise of the Voltage Amplifier
:PROPERTIES:
:header-args:matlab+: :tangle meas_volt_amp.m
:header-args:matlab+: :comments org :mkdirp yes
:END:
#+begin_src bash :exports none :results none
zip data/meas_volt_amp \
mat/data_003.mat \
mat/data_004.mat \
mat/data_005.mat \
mat/data_006.mat \
meas_volt_amp.m
#+end_src
The data and matlab files are accessible [[file:data/meas_volt_amp.zip][here]].
** Measurement Description
*Goal*:
- Determine the Voltage Amplifier noise
*Setup*:
- The two inputs (differential) of the voltage amplifier are shunted with 50Ohms
- The AC/DC option of the Voltage amplifier is on AC
- The low pass filter is set to 1hHz
- We measure the output of the voltage amplifier with a 16bits ADC of the Speedgoat
*Measurements*:
- =data_003=: Ampli OFF
- =data_004=: Ampli ON set to 20dB
- =data_005=: Ampli ON set to 40dB
- =data_006=: Ampli ON set to 60dB
** Matlab Init :noexport:ignore:
#+begin_src matlab :exports none :results silent :noweb yes
<<matlab-init>>
#+end_src
** Load data
#+begin_src matlab :results none
amp_off = load('mat/data_003.mat', 'data'); amp_off = amp_off.data(:, [1,3]);
amp_20d = load('mat/data_004.mat', 'data'); amp_20d = amp_20d.data(:, [1,3]);
amp_40d = load('mat/data_005.mat', 'data'); amp_40d = amp_40d.data(:, [1,3]);
amp_60d = load('mat/data_006.mat', 'data'); amp_60d = amp_60d.data(:, [1,3]);
#+end_src
** Time Domain
The time domain signals are shown on figure [[fig:ampli_noise_time]].
#+begin_src matlab :results none :exports none
figure;
hold on;
plot(amp_off(:, 2), amp_off(:, 1), 'DisplayName', 'OFF');
plot(amp_20d(:, 2), amp_20d(:, 1), 'DisplayName', '20dB');
plot(amp_40d(:, 2), amp_40d(:, 1), 'DisplayName', '40dB');
plot(amp_60d(:, 2), amp_60d(:, 1), 'DisplayName', '60dB');
hold off;
legend('Location', 'northeast');
xlabel('Time [s]');
ylabel('Voltage [V]');
#+end_src
#+NAME: fig:ampli_noise_time
#+HEADER: :tangle no :exports results :results value raw replace :noweb yes
#+begin_src matlab :var filepath="figs/ampli_noise_time.pdf" :var figsize="wide-normal" :post pdf2svg(file=*this*, ext="png")
<<plt-matlab>>
#+end_src
#+NAME: fig:ampli_noise_time
#+CAPTION: Output of the amplifier
#+RESULTS: fig:ampli_noise_time
[[file:figs/ampli_noise_time.png]]
** Frequency Domain
We first compute some parameters that will be used for the PSD computation.
#+begin_src matlab :results none
dt = amp_off(2, 2)-amp_off(1, 2);
Fs = 1/dt; % [Hz]
win = hanning(ceil(10*Fs));
#+end_src
Then we compute the Power Spectral Density using =pwelch= function.
#+begin_src matlab :results none
[pxoff, f] = pwelch(amp_off(:,1), win, [], [], Fs);
[px20d, ~] = pwelch(amp_20d(:,1), win, [], [], Fs);
[px40d, ~] = pwelch(amp_40d(:,1), win, [], [], Fs);
[px60d, ~] = pwelch(amp_60d(:,1), win, [], [], Fs);
#+end_src
We compute the theoretical ADC noise.
#+begin_src matlab :results none
q = 20/2^16; % quantization
Sq = q^2/12/1000; % PSD of the ADC noise
#+end_src
Finally, the ASD is shown on figure [[fig:ampli_noise_psd]].
#+begin_src matlab :results none :exports none
figure;
hold on;
plot(f, sqrt(pxoff), 'DisplayName', 'OFF');
plot(f, sqrt(px20d), 'DisplayName', '20dB');
plot(f, sqrt(px40d), 'DisplayName', '40dB');
plot(f, sqrt(px60d), 'DisplayName', '60dB');
plot([0.1, 500], [sqrt(Sq), sqrt(Sq)], 'k--');
hold off;
set(gca, 'xscale', 'log');
set(gca, 'yscale', 'log');
xlabel('Frequency [Hz]'); ylabel('ASD of the measured Voltage $\left[\frac{V}{\sqrt{Hz}}\right]$')
legend('Location', 'northeast');
xlim([0.1, 500]);
#+end_src
#+NAME: fig:ampli_noise_psd
#+HEADER: :tangle no :exports results :results value raw replace :noweb yes
#+begin_src matlab :var filepath="figs/ampli_noise_psd.pdf" :var figsize="full-tall" :post pdf2svg(file=*this*, ext="png")
<<plt-matlab>>
#+end_src
#+NAME: fig:ampli_noise_psd
#+CAPTION: Amplitude Spectral Density of the measured voltage at the output of the voltage amplifier
#+RESULTS: fig:ampli_noise_psd
[[file:figs/ampli_noise_psd.png]]
** Conclusion
#+begin_important
Noise induced by the voltage amplifiers is not a limiting factor.
#+end_important
* Measure of the noise induced by the Slip-Ring
:PROPERTIES:
:header-args:matlab+: :tangle meas_slip_ring.m
:header-args:matlab+: :comments org :mkdirp yes
:END:
#+begin_src bash :exports none :results none
zip data/meas_slip_ring \
mat/data_008.mat \
mat/data_009.mat \
mat/data_010.mat \
mat/data_011.mat \
meas_slip_ring.m
#+end_src
The data and matlab files are accessible [[file:data/meas_slip_ring.zip][here]].
** Measurement Description
*Goal*:
- Determine the noise induced by the slip-ring
*Setup*:
- 0V is generated by the DAC of the Speedgoat
- Using a T, one part goes directly to the ADC
- The other part goes to the slip-ring 2 times and then to the ADC
- The parameters of the Voltage Amplifier are: 80dB, AC, 1kHz
- Every stage of the station is OFF
First column: Direct measure
Second column: Slip-ring measure
*Measurements*:
- =data_008=: Slip-Ring OFF
- =data_009=: Slip-Ring ON
- =data_010=: Slip-Ring ON and omega=6rpm
- =data_011=: Slip-Ring ON and omega=60rpm
** Matlab Init :noexport:ignore:
#+begin_src matlab :exports none :results silent :noweb yes
<<matlab-init>>
#+end_src
** Load data
We load the data of the z axis of two geophones.
#+begin_src matlab :results none
sr_off = load('mat/data_008.mat', 'data'); sr_off = sr_off.data;
sr_on = load('mat/data_009.mat', 'data'); sr_on = sr_on.data;
sr_6r = load('mat/data_010.mat', 'data'); sr_6r = sr_6r.data;
sr_60r = load('mat/data_011.mat', 'data'); sr_60r = sr_60r.data;
#+end_src
** Time Domain
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]]);
#+begin_src matlab :results none :exports none
figure;
hold on;
plot(sr_60r(:, 3), sr_60r(:, 1), 'DisplayName', '60rpm');
plot(sr_6r(:, 3), sr_6r(:, 1), 'DisplayName', '6rpm');
plot(sr_on(:, 3), sr_on(:, 1), 'DisplayName', 'ON');
plot(sr_off(:, 3), sr_off(:, 1), 'DisplayName', 'OFF');
hold off;
xlabel('Time [s]'); ylabel('Voltage [V]');
legend('Location', 'northeast');
#+end_src
#+NAME: fig:sr_direct_time
#+HEADER: :tangle no :exports results :results value raw replace :noweb yes
#+begin_src matlab :var filepath="figs/sr_direct_time.pdf" :var figsize="wide-normal" :post pdf2svg(file=*this*, ext="png")
<<plt-matlab>>
#+end_src
#+NAME: fig:sr_direct_time
#+CAPTION: Direct measurement
#+RESULTS: fig:sr_direct_time
[[file:figs/sr_direct_time.png]]
#+begin_src matlab :results none :exports none
figure;
hold on;
plot(sr_60r(:, 3), sr_60r(:, 2), 'DisplayName', '60rpm');
plot(sr_6r(:, 3), sr_6r(:, 2), 'DisplayName', '6rpm');
plot(sr_on(:, 3), sr_on(:, 2), 'DisplayName', 'ON');
plot(sr_off(:, 3), sr_off(:, 2), 'DisplayName', 'OFF');
hold off;
xlabel('Time [s]'); ylabel('Voltage [V]');
legend('Location', 'northeast');
#+end_src
#+NAME: fig:sr_slipring_time
#+HEADER: :tangle no :exports results :results value raw replace :noweb yes
#+begin_src matlab :var filepath="figs/sr_slipring_time.pdf" :var figsize="wide-normal" :post pdf2svg(file=*this*, ext="png")
<<plt-matlab>>
#+end_src
#+NAME: fig:sr_slipring_time
#+CAPTION: Measurement of the signal going through the Slip-Ring
#+RESULTS: fig:sr_slipring_time
[[file:figs/sr_slipring_time.png]]
** Frequency Domain
We first compute some parameters that will be used for the PSD computation.
#+begin_src matlab :results none
dt = sr_off(2, 3)-sr_off(1, 3);
Fs = 1/dt; % [Hz]
win = hanning(ceil(10*Fs));
#+end_src
Then we compute the Power Spectral Density using =pwelch= function.
#+begin_src matlab :results none
[pxdir, f] = pwelch(sr_off(:, 1), win, [], [], Fs);
[pxoff, ~] = pwelch(sr_off(:, 2), win, [], [], Fs);
[pxon, ~] = pwelch(sr_on(:, 2), win, [], [], Fs);
[px6r, ~] = pwelch(sr_6r(:, 2), win, [], [], Fs);
[px60r, ~] = pwelch(sr_60r(:, 2), win, [], [], Fs);
#+end_src
And we plot the ASD of the measured signals (figure [[fig:sr_psd_compare]]);
#+begin_src matlab :results none
figure;
hold on;
plot(f, sqrt(pxoff), 'DisplayName', 'OFF');
plot(f, sqrt(pxon), 'DisplayName', 'ON');
plot(f, sqrt(px6r), 'DisplayName', '6rpm');
plot(f, sqrt(px60r), 'DisplayName', '60rpm');
plot(f, sqrt(pxdir), 'k-', 'DisplayName', 'Direct');
hold off;
set(gca, 'xscale', 'log');
set(gca, 'yscale', 'log');
xlabel('Frequency [Hz]'); ylabel('ASD of the measured Voltage $\left[\frac{V}{\sqrt{Hz}}\right]$')
legend('Location', 'northeast');
xlim([0.1, 500]);
#+end_src
#+NAME: fig:sr_psd_compare
#+HEADER: :tangle no :exports results :results value raw replace :noweb yes
#+begin_src matlab :var filepath="figs/sr_psd_compare.pdf" :var figsize="full-tall" :post pdf2svg(file=*this*, ext="png")
<<plt-matlab>>
#+end_src
#+NAME: fig:sr_psd_compare
#+CAPTION: Comparison of the ASD of the measured signals when the slip-ring is ON, OFF and turning
#+RESULTS: fig:sr_psd_compare
[[file:figs/sr_psd_compare.png]]
** Conclusion
#+begin_important
#+end_important
* Measure of the noise induced by the slip ring when using a geophone
:PROPERTIES:
:header-args:matlab+: :tangle meas_sr_geophone.m
:header-args:matlab+: :comments org :mkdirp yes
:END:
#+begin_src bash :exports none :results none
zip data/meas_sr_geophone \
mat/data_012.mat \
mat/data_013.mat \
meas_sr_geophone.m
#+end_src
The data and matlab files are accessible [[file:data/meas_sr_geophone.zip][here]].
** Measurement Description
*Goal*:
- Determine if the noise induced by the slip-ring is a limiting factor when measuring the signal coming from a geophone
*Setup*:
- The geophone is located at the sample location
- The two Voltage amplifiers have the following settings:
- AC
- 60dB
- 1kHz
- The signal from the geophone is split into two using a T-BNC:
- One part goes directly to the voltage amplifier and then to the ADC.
- The other part goes to the slip-ring=>voltage amplifier=>ADC.
First column: Direct measure
Second column: Slip-ring measure
*Measurements*:
- =data_012=: Slip-Ring OFF
- =data_013=: Slip-Ring ON
** Matlab Init :noexport:ignore:
#+begin_src matlab :exports none :results silent :noweb yes
<<matlab-init>>
#+end_src
** Load data
We load the data of the z axis of two geophones.
#+begin_src matlab :results none
sr_off = load('mat/data_012.mat', 'data'); sr_off = sr_off.data;
sr_on = load('mat/data_013.mat', 'data'); sr_on = sr_on.data;
#+end_src
** Time Domain
We compare the signal when the Slip-Ring is OFF (figure [[fig:sr_geophone_time_off]]) and when it is ON (figure [[fig:sr_geophone_time_on]]).
#+begin_src matlab :results none :exports none
figure;
hold on;
plot(sr_off(:, 3), sr_off(:, 1), 'DisplayName', 'Direct');
plot(sr_off(:, 3), sr_off(:, 2), 'DisplayName', 'Slip-Ring');
hold off;
legend('Location', 'northeast');
xlabel('Time [s]');
ylabel('Voltage [V]');
#+end_src
#+NAME: fig:sr_geophone_time_off
#+HEADER: :tangle no :exports results :results value raw replace :noweb yes
#+begin_src matlab :var filepath="figs/sr_geophone_time_off.pdf" :var figsize="wide-normal" :post pdf2svg(file=*this*, ext="png")
<<plt-matlab>>
#+end_src
#+NAME: fig:sr_geophone_time_off
#+CAPTION: Comparison of the time domain signals when the slip-ring is OFF
#+RESULTS: fig:sr_geophone_time_off
[[file:figs/sr_geophone_time_off.png]]
#+begin_src matlab :results none :exports none
figure;
hold on;
plot(sr_on(:, 3), sr_on(:, 1), 'DisplayName', 'Direct');
plot(sr_on(:, 3), sr_on(:, 2), 'DisplayName', 'Slip-Ring');
hold off;
legend('Location', 'northeast');
xlabel('Time [s]');
ylabel('Voltage [V]');
#+end_src
#+NAME: fig:sr_geophone_time_on
#+HEADER: :tangle no :exports results :results value raw replace :noweb yes
#+begin_src matlab :var filepath="figs/sr_geophone_time_on.pdf" :var figsize="wide-normal" :post pdf2svg(file=*this*, ext="png")
<<plt-matlab>>
#+end_src
#+NAME: fig:sr_geophone_time_on
#+CAPTION: Comparison of the time domain signals when the slip-ring is ON
#+RESULTS: fig:sr_geophone_time_on
[[file:figs/sr_geophone_time_on.png]]
** Frequency Domain
We first compute some parameters that will be used for the PSD computation.
#+begin_src matlab :results none
dt = sr_off(2, 3)-sr_off(1, 3);
Fs = 1/dt; % [Hz]
win = hanning(ceil(10*Fs));
#+end_src
Then we compute the Power Spectral Density using =pwelch= function.
#+begin_src matlab :results none
% Direct measure
[pxdoff, ~] = pwelch(sr_off(:, 1), win, [], [], Fs);
[pxdon, ~] = pwelch(sr_on(:, 1), win, [], [], Fs);
% Slip-Ring measure
[pxsroff, f] = pwelch(sr_off(:, 2), win, [], [], Fs);
[pxsron, ~] = pwelch(sr_on(:, 2), win, [], [], Fs);
#+end_src
Finally, we compare the Amplitude Spectral Density of the signals (figure [[]]);
#+begin_src matlab :results none
figure;
hold on;
plot(f, sqrt(pxdoff), 'DisplayName', 'Direct - OFF');
plot(f, sqrt(pxsroff), 'DisplayName', 'Slip-Ring - OFF');
plot(f, sqrt(pxdon), 'DisplayName', 'Direct - ON');
plot(f, sqrt(pxsron), 'DisplayName', 'Slip-Ring - ON');
hold off;
set(gca, 'xscale', 'log');
set(gca, 'yscale', 'log');
xlabel('Frequency [Hz]'); ylabel('ASD of the measured Voltage $\left[\frac{V}{\sqrt{Hz}}\right]$')
legend('Location', 'northeast');
xlim([0.1, 500]);
#+end_src
#+NAME: fig:sr_geophone_asd
#+HEADER: :tangle no :exports results :results value raw replace :noweb yes
#+begin_src matlab :var filepath="figs/sr_geophone_asd.pdf" :var figsize="full-tall" :post pdf2svg(file=*this*, ext="png")
<<plt-matlab>>
#+end_src
#+NAME: fig:sr_geophone_asd
#+CAPTION: Comparison of the Amplitude Spectral Sensity
#+RESULTS: fig:sr_geophone_asd
[[file:figs/sr_geophone_asd.png]]
#+begin_src matlab :results none :exports none
xlim([100, 500]);
#+end_src
#+NAME: fig:sr_geophone_asd_zoom
#+HEADER: :tangle no :exports results :results value raw replace :noweb yes
#+begin_src matlab :var filepath="figs/sr_geophone_asd_zoom.pdf" :var figsize="full-tall" :post pdf2svg(file=*this*, ext="png")
<<plt-matlab>>
#+end_src
#+NAME: fig:sr_geophone_asd_zoom
#+CAPTION: Comparison of the Amplitude Spectral Sensity - Zoom
#+RESULTS: fig:sr_geophone_asd_zoom
[[file:figs/sr_geophone_asd_zoom.png]]
** Conclusion
#+begin_important
- When the slip-ring is OFF, it does not add any noise to the measurement
- When the slip-ring is ON, it adds significant noise to the signal
#+end_important
* Measure of the influence of the AC/DC option on the voltage amplifiers
:PROPERTIES:
:header-args:matlab+: :tangle meas_noise_ac_dc.m
:header-args:matlab+: :comments org :mkdirp yes
:END:
#+begin_src bash :exports none :results none
zip data/meas_noise_ac_dc \
mat/data_012.mat \
mat/data_013.mat \
meas_noise_ac_dc.m
#+end_src
The data and matlab files are accessible [[file:data/meas_noise_ac_dc.zip][here]].
** Measurement Description
*Goal*:
- Measure the influence of the high-pass filter option of the voltage amplifiers
*Setup*:
- One geophone is located on the marble.
- It's signal goes to two voltage amplifiers with a gain of 60dB.
- One voltage amplifier is on the AC option, the other is on the DC option.
*Measurements*:
First measurement (=mat/data_014.mat= file):
| Column | Signal |
|--------+----------------------------|
| 1 | Amplifier 1 with AC option |
| 2 | Amplifier 2 with DC option |
| 3 | Time |
Second measurement (=mat/data_015.mat= file):
| Column | Signal |
|--------+----------------------------|
| 1 | Amplifier 1 with DC option |
| 2 | Amplifier 2 with AC option |
| 3 | Time |
** Matlab Init :noexport:ignore:
#+begin_src matlab :exports none :results silent :noweb yes
<<matlab-init>>
#+end_src
** Load data
We load the data of the z axis of two geophones.
#+begin_src matlab :results none
meas14 = load('mat/data_014.mat', 'data'); meas14 = meas14.data;
meas15 = load('mat/data_015.mat', 'data'); meas15 = meas15.data;
#+end_src
** Time Domain
The signals are shown on figure [[fig:ac_dc_option_time]].
#+begin_src matlab :results none :exports none
figure;
hold on;
plot(meas14(:, 3), meas14(:, 1), 'DisplayName', 'Amp1 - AC');
plot(meas14(:, 3), meas14(:, 2), 'DisplayName', 'Amp2 - DC');
plot(meas15(:, 3), meas15(:, 1), 'DisplayName', 'Amp1 - DC');
plot(meas15(:, 3), meas15(:, 2), 'DisplayName', 'Amp2 - AC');
hold off;
legend('Location', 'northeast');
xlabel('Time [s]');
ylabel('Voltage [V]');
xlim([0, 100]);
#+end_src
#+NAME: fig:ac_dc_option_time
#+HEADER: :tangle no :exports results :results value raw replace :noweb yes
#+begin_src matlab :var filepath="figs/ac_dc_option_time.pdf" :var figsize="wide-normal" :post pdf2svg(file=*this*, ext="png")
<<plt-matlab>>
#+end_src
#+NAME: fig:ac_dc_option_time
#+CAPTION: Comparison of the signals going through the Voltage amplifiers
#+RESULTS: fig:ac_dc_option_time
[[file:figs/ac_dc_option_time.png]]
** Frequency Domain
We first compute some parameters that will be used for the PSD computation.
#+begin_src matlab :results none
dt = meas14(2, 3)-meas14(1, 3);
Fs = 1/dt; % [Hz]
win = hanning(ceil(10*Fs));
#+end_src
Then we compute the Power Spectral Density using =pwelch= function.
#+begin_src matlab :results none
[pxamp1ac, f] = pwelch(meas14(:, 1), win, [], [], Fs);
[pxamp2dc, ~] = pwelch(meas14(:, 2), win, [], [], Fs);
[pxamp1dc, ~] = pwelch(meas15(:, 1), win, [], [], Fs);
[pxamp2ac, ~] = pwelch(meas15(:, 2), win, [], [], Fs);
#+end_src
The ASD of the signals are compare on figure [[fig:ac_dc_option_asd]].
#+begin_src matlab :results none :exports none
figure;
hold on;
plot(f, sqrt(pxamp1ac), 'DisplayName', 'Amp1 - AC');
plot(f, sqrt(pxamp2dc), 'DisplayName', 'Amp2 - DC');
plot(f, sqrt(pxamp1dc), 'DisplayName', 'Amp1 - DC');
plot(f, sqrt(pxamp2ac), 'DisplayName', 'Amp2 - AC');
hold off;
set(gca, 'xscale', 'log');
set(gca, 'yscale', 'log');
xlabel('Frequency [Hz]'); ylabel('ASD of the measured Voltage $\left[\frac{V}{\sqrt{Hz}}\right]$')
legend('Location', 'northeast');
xlim([0.1, 500]);
#+end_src
#+NAME: fig:ac_dc_option_asd
#+HEADER: :tangle no :exports results :results value raw replace :noweb yes
#+begin_src matlab :var filepath="figs/ac_dc_option_asd.pdf" :var figsize="full-tall" :post pdf2svg(file=*this*, ext="png")
<<plt-matlab>>
#+end_src
#+NAME: fig:ac_dc_option_asd
#+CAPTION: Amplitude Spectral Density of the measured signals
#+RESULTS: fig:ac_dc_option_asd
[[file:figs/ac_dc_option_asd.png]]
** Conclusion
#+begin_important
#+end_important

15
slip-ring-test/readme.org
View File

@ -1,4 +1,5 @@
* Measure of the noise of the Voltage Amplifier * DONE Measure of the noise of the Voltage Amplifier
CLOSED: [2019-05-06 lun. 09:00]
- The two inputs (differential) of the voltage amplifier are shunted with 50Ohms - The two inputs (differential) of the voltage amplifier are shunted with 50Ohms
- The AC/DC option of the Voltage amplifier is on AC - The AC/DC option of the Voltage amplifier is on AC
- The low pass filter is set to 1hHz - The low pass filter is set to 1hHz
@ -11,7 +12,8 @@ meas5: Ampli ON 40dB
meas6: Ampli ON 60dB meas6: Ampli ON 60dB
meas7: Ampli ON 80dB meas7: Ampli ON 80dB
* Measure of the noise induced by the Slip-Ring * DONE Measure of the noise induced by the Slip-Ring
CLOSED: [2019-05-06 lun. 09:28]
Setup: Setup:
- 0V is generated by the DAC of the Speedgoat - 0V is generated by the DAC of the Speedgoat
- Using a T, one part goes to ADC - Using a T, one part goes to ADC
@ -30,8 +32,8 @@ Measurements:
- meas10: Slip-Ring ON and omega=6rpm - meas10: Slip-Ring ON and omega=6rpm
- meas11: Slip-Ring ON and omega=60rpm - meas11: Slip-Ring ON and omega=60rpm
* Measure of the noise induced by the slip ring when using a geophone * DONE Measure of the noise induced by the slip ring when using a geophone
CLOSED: [2019-05-06 lun. 09:28]
The geophone is located at the sample location The geophone is located at the sample location
The two Voltage amplifiers have the following settings: The two Voltage amplifiers have the following settings:
- AC - AC
@ -51,8 +53,8 @@ Second column: Slip-ring measure
- meas12: Slip-Ring OFF - meas12: Slip-Ring OFF
- meas13: Slip-Ring ON - meas13: Slip-Ring ON
* Measure of the influence of the AC/DC option on the voltage amplifiers * DONE Measure of the influence of the AC/DC option on the voltage amplifiers
CLOSED: [2019-05-06 lun. 09:28]
One geophone is located on the marble. One geophone is located on the marble.
It's signal goes to two voltage amplifiers with a gain of 60dB. It's signal goes to two voltage amplifiers with a gain of 60dB.
On voltage amplifier is on the AC option, the other on the DC option. On voltage amplifier is on the AC option, the other on the DC option.
@ -62,4 +64,3 @@ Second column: DC
- meas14: col-1 = amp1+AC. col-2 = amp2+DC. - meas14: col-1 = amp1+AC. col-2 = amp2+DC.
- meas15: col-1 = amp1+DC. col-2 = amp2+AC. - meas15: col-1 = amp1+DC. col-2 = amp2+AC.