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"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<!-- 2019-05-16 jeu. 13:39 -->
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<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<title>Measurements On the Slip-Ring - Electrical Noise</title>
@@ -280,49 +280,51 @@ for the JavaScript code in this tag.
<h2>Table of Contents</h2>
<div id="text-table-of-contents">
<ul>
<li><a href="#org705b8cd">1. Effect of the Slip-Ring on the signal when turned ON - Geophone measurement</a>
<li><a href="#orgd65df36">1. Effect of the Slip-Ring on the signal when turned ON - Geophone measurement</a>
<ul>
<li><a href="#org27dcdf9">1.1. Experimental Setup</a></li>
<li><a href="#orgba60edf">1.2. Load data</a></li>
<li><a href="#orgbf72b36">1.3. Analysis - Time Domain</a></li>
<li><a href="#org71bcce4">1.4. Analysis - Frequency Domain</a></li>
<li><a href="#orge2e072d">1.5. Conclusion</a></li>
<li><a href="#org452b75e">1.1. Experimental Setup</a></li>
<li><a href="#org022d10a">1.2. Load data</a></li>
<li><a href="#org0e16286">1.3. Analysis - Time Domain</a></li>
<li><a href="#org56d1423">1.4. Analysis - Frequency Domain</a></li>
<li><a href="#org0148c7b">1.5. Conclusion</a></li>
</ul>
</li>
<li><a href="#org3ccfaf0">2. Measure of the noise induced by the Slip-Ring using voltage amplifiers - Geophone</a>
<li><a href="#orgc83e3c2">2. Measure of the noise induced by the Slip-Ring using voltage amplifiers - Geophone</a>
<ul>
<li><a href="#org6a0af97">2.1. First Measurement without LPF</a>
<li><a href="#org4234d00">2.1. First Measurement without LPF</a>
<ul>
<li><a href="#org8149c88">2.1.1. Measurement Description</a></li>
<li><a href="#orgb24a472">2.1.2. Load data</a></li>
<li><a href="#org1ed7f66">2.1.3. Time Domain</a></li>
<li><a href="#orgfb4b1b3">2.1.4. Frequency Domain</a></li>
<li><a href="#org8df486d">2.1.5. Conclusion</a></li>
<li><a href="#orgb3448f0">2.1.1. Measurement Description</a></li>
<li><a href="#org769f767">2.1.2. Load data</a></li>
<li><a href="#orgab936f6">2.1.3. Time Domain</a></li>
<li><a href="#orga860ebc">2.1.4. Frequency Domain</a></li>
<li><a href="#org2f13e1b">2.1.5. Conclusion</a></li>
</ul>
</li>
<li><a href="#org5a500b8">2.2. Measurement using an oscilloscope</a>
<li><a href="#org09f7fe0">2.2. Measurement using an oscilloscope</a>
<ul>
<li><a href="#orgb213fc5">2.2.1. Measurement Setup</a></li>
<li><a href="#orgc19f828">2.2.2. Observations</a></li>
<li><a href="#org61930e6">2.2.3. Conclusion</a></li>
<li><a href="#org05d3686">2.2.1. Measurement Setup</a></li>
<li><a href="#org31ccfad">2.2.2. Observations</a></li>
<li><a href="#org6b078b2">2.2.3. Conclusion</a></li>
</ul>
</li>
<li><a href="#orgb00f95d">2.3. New measurements with a LPF before the Voltage Amplifiers</a>
<li><a href="#org70c9bc1">2.3. New measurements with a LPF before the Voltage Amplifiers</a>
<ul>
<li><a href="#org9fa4c9c">2.3.1. Setup description</a></li>
<li><a href="#org56ffeb4">2.3.2. Load data</a></li>
<li><a href="#orgcabd836">2.3.3. Time Domain</a></li>
<li><a href="#org50b3d2c">2.3.4. Frequency Domain</a></li>
<li><a href="#org2a4f07d">2.3.5. Conclusion</a></li>
<li><a href="#org64b7d09">2.3.1. Setup description</a></li>
<li><a href="#org5426009">2.3.2. Load data</a></li>
<li><a href="#orgb76acbe">2.3.3. Time Domain</a></li>
<li><a href="#orgbef3f23">2.3.4. Frequency Domain</a></li>
<li><a href="#orgc1fcca7">2.3.5. Conclusion</a></li>
</ul>
</li>
<li><a href="#orgd55b3f8">2.4. Measurement of the noise induced by the slip-ring with additional LPF at 1kHz</a>
<li><a href="#orga70c2df">2.4. Measurement of the noise induced by the slip-ring with additional LPF at 1kHz</a>
<ul>
<li><a href="#org469d03f">2.4.1. Measurement description</a></li>
<li><a href="#org6bf316b">2.4.2. Load data</a></li>
<li><a href="#orga099a0e">2.4.3. Time Domain</a></li>
<li><a href="#org879b6b3">2.4.4. Frequency Domain</a></li>
<li><a href="#orgc1bf114">2.4.5. Conclusion</a></li>
<li><a href="#orgc629012">2.4.1. Measurement description</a></li>
<li><a href="#org04e8d20">2.4.2. Load data</a></li>
<li><a href="#org8394ea8">2.4.3. Pre-processing</a></li>
<li><a href="#orgd37877e">2.4.4. Time Domain</a></li>
<li><a href="#orgc77f23c">2.4.5. Frequency Domain</a></li>
<li><a href="#org92d0230">2.4.6. Difference between the direct signal and the signal going through the slip-ring</a></li>
<li><a href="#orga9ca1a2">2.4.7. Conclusion</a></li>
</ul>
</li>
</ul>
@@ -335,12 +337,12 @@ for the JavaScript code in this tag.
The noise induced by the slip-ring is measured when using geophones:
</p>
<ul class="org-ul">
<li>Section <a href="#org6429a42">1</a>:
<li>Section <a href="#org3ad3d26">1</a>:
<ul class="org-ul">
<li>A geophone located at the sample location is measured with its signal going directly to the ADC and going through the slip-ring</li>
<li>The voltage amplifiers where saturating due to high frequency noise</li>
</ul></li>
<li>Section <a href="#org76451eb">2</a>:
<li>Section <a href="#orgd23ef9b">2</a>:
<ul class="org-ul">
<li>A Low Pass Filter is added before the voltage amplifiers</li>
<li>Using a Oscilloscope, high frequency noise at 40kHz generated by the slip-ring has been identified</li>
@@ -348,11 +350,11 @@ The noise induced by the slip-ring is measured when using geophones:
</ul></li>
</ul>
<div id="outline-container-org705b8cd" class="outline-2">
<h2 id="org705b8cd"><span class="section-number-2">1</span> Effect of the Slip-Ring on the signal when turned ON - Geophone measurement</h2>
<div id="outline-container-orgd65df36" class="outline-2">
<h2 id="orgd65df36"><span class="section-number-2">1</span> Effect of the Slip-Ring on the signal when turned ON - Geophone measurement</h2>
<div class="outline-text-2" id="text-1">
<p>
<a id="org6429a42"></a>
<a id="org3ad3d26"></a>
</p>
<div class="note">
<p>
@@ -362,8 +364,8 @@ All the files (data and Matlab scripts) are accessible <a href="data/meas_slip_r
</div>
</div>
<div id="outline-container-org27dcdf9" class="outline-3">
<h3 id="org27dcdf9"><span class="section-number-3">1.1</span> Experimental Setup</h3>
<div id="outline-container-org452b75e" class="outline-3">
<h3 id="org452b75e"><span class="section-number-3">1.1</span> Experimental Setup</h3>
<div class="outline-text-3" id="text-1-1">
<p>
<b>Goal</b>:
@@ -377,7 +379,7 @@ Two measurements are made with the control systems of all the stages turned OFF.
</p>
<p>
One geophone is located on the marble while the other is located at the sample location (figure <a href="#org8bb3417">1</a>).
One geophone is located on the marble while the other is located at the sample location (figure <a href="#org37037f9">1</a>).
</p>
<p>
@@ -390,7 +392,7 @@ The two signals from the geophones are amplified with voltage amplifiers with th
</ul>
<div id="org8bb3417" class="figure">
<div id="org37037f9" class="figure">
<p><img src="./img/IMG_20190430_112615.jpg" alt="IMG_20190430_112615.jpg" width="500px" />
</p>
<p><span class="figure-number">Figure 1: </span>Experimental Setup</p>
@@ -465,8 +467,8 @@ Each of the measurement <code>mat</code> file contains one <code>data</code> arr
</div>
</div>
<div id="outline-container-orgba60edf" class="outline-3">
<h3 id="orgba60edf"><span class="section-number-3">1.2</span> Load data</h3>
<div id="outline-container-org022d10a" class="outline-3">
<h3 id="org022d10a"><span class="section-number-3">1.2</span> Load data</h3>
<div class="outline-text-3" id="text-1-2">
<p>
We load the data of the z axis of two geophones.
@@ -480,11 +482,11 @@ meas_di = load<span class="org-rainbow-delimiters-depth-1">(</span>'mat<span cla
</div>
</div>
<div id="outline-container-orgbf72b36" class="outline-3">
<h3 id="orgbf72b36"><span class="section-number-3">1.3</span> Analysis - Time Domain</h3>
<div id="outline-container-org0e16286" class="outline-3">
<h3 id="org0e16286"><span class="section-number-3">1.3</span> Analysis - Time Domain</h3>
<div class="outline-text-3" id="text-1-3">
<p>
First, we compare the time domain signals for the two experiments (figure <a href="#org3f972d3">2</a>).
First, we compare the time domain signals for the two experiments (figure <a href="#org5c6d734">2</a>).
</p>
<div class="org-src-container">
@@ -500,7 +502,7 @@ legend<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-stri
</div>
<div id="org3f972d3" class="figure">
<div id="org5c6d734" class="figure">
<p><img src="figs/slipring_time.png" alt="slipring_time.png" />
</p>
<p><span class="figure-number">Figure 2: </span>Effect of the Slip-Ring on the measured signal of the geophone at the sample location - Time domain</p>
@@ -508,11 +510,11 @@ legend<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-stri
</div>
</div>
<div id="outline-container-org71bcce4" class="outline-3">
<h3 id="org71bcce4"><span class="section-number-3">1.4</span> Analysis - Frequency Domain</h3>
<div id="outline-container-org56d1423" class="outline-3">
<h3 id="org56d1423"><span class="section-number-3">1.4</span> Analysis - Frequency Domain</h3>
<div class="outline-text-3" id="text-1-4">
<p>
We then compute the Power Spectral Density of the two signals and we compare them (figure <a href="#orgf7500fb">3</a>).
We then compute the Power Spectral Density of the two signals and we compare them (figure <a href="#org50a7973">3</a>).
</p>
<div class="org-src-container">
@@ -544,7 +546,7 @@ legend<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-stri
</div>
<div id="orgf7500fb" class="figure">
<div id="org50a7973" class="figure">
<p><img src="figs/slipring_asd.png" alt="slipring_asd.png" />
</p>
<p><span class="figure-number">Figure 3: </span>Effect of the Slip-Ring on the measured signal of the geophone at the sample location - Frequency domain</p>
@@ -552,12 +554,12 @@ legend<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-stri
</div>
</div>
<div id="outline-container-orge2e072d" class="outline-3">
<h3 id="orge2e072d"><span class="section-number-3">1.5</span> Conclusion</h3>
<div id="outline-container-org0148c7b" class="outline-3">
<h3 id="org0148c7b"><span class="section-number-3">1.5</span> Conclusion</h3>
<div class="outline-text-3" id="text-1-5">
<div class="important">
<ul class="org-ul">
<li>The voltage amplifiers are saturating during the measurements (as shown by the LED on figure <a href="#org8bb3417">1</a>)</li>
<li>The voltage amplifiers are saturating during the measurements (as shown by the LED on figure <a href="#org37037f9">1</a>)</li>
<li>This saturation is mainly due to high frequency noise =&gt; a LPF will be added at the input of the voltage amplifiers in the further measurements</li>
<li>The measurements will be redone</li>
</ul>
@@ -567,11 +569,11 @@ legend<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-stri
</div>
</div>
<div id="outline-container-org3ccfaf0" class="outline-2">
<h2 id="org3ccfaf0"><span class="section-number-2">2</span> Measure of the noise induced by the Slip-Ring using voltage amplifiers - Geophone</h2>
<div id="outline-container-orgc83e3c2" class="outline-2">
<h2 id="orgc83e3c2"><span class="section-number-2">2</span> Measure of the noise induced by the Slip-Ring using voltage amplifiers - Geophone</h2>
<div class="outline-text-2" id="text-2">
<p>
<a id="org76451eb"></a>
<a id="orgd23ef9b"></a>
</p>
<div class="note">
<p>
@@ -581,12 +583,12 @@ All the files (data and Matlab scripts) are accessible <a href="data/meas_sr_geo
</div>
</div>
<div id="outline-container-org6a0af97" class="outline-3">
<h3 id="org6a0af97"><span class="section-number-3">2.1</span> First Measurement without LPF</h3>
<div id="outline-container-org4234d00" class="outline-3">
<h3 id="org4234d00"><span class="section-number-3">2.1</span> First Measurement without LPF</h3>
<div class="outline-text-3" id="text-2-1">
</div>
<div id="outline-container-org8149c88" class="outline-4">
<h4 id="org8149c88"><span class="section-number-4">2.1.1</span> Measurement Description</h4>
<div id="outline-container-orgb3448f0" class="outline-4">
<h4 id="orgb3448f0"><span class="section-number-4">2.1.1</span> Measurement Description</h4>
<div class="outline-text-4" id="text-2-1-1">
<p>
<b>Goal</b>:
@@ -679,8 +681,8 @@ Each of the measurement <code>mat</code> file contains one <code>data</code> arr
</div>
</div>
<div id="outline-container-orgb24a472" class="outline-4">
<h4 id="orgb24a472"><span class="section-number-4">2.1.2</span> Load data</h4>
<div id="outline-container-org769f767" class="outline-4">
<h4 id="org769f767"><span class="section-number-4">2.1.2</span> Load data</h4>
<div class="outline-text-4" id="text-2-1-2">
<p>
We load the data of the z axis of two geophones.
@@ -693,22 +695,22 @@ sr_on = load<span class="org-rainbow-delimiters-depth-1">(</span><span class="o
</div>
</div>
<div id="outline-container-org1ed7f66" class="outline-4">
<h4 id="org1ed7f66"><span class="section-number-4">2.1.3</span> Time Domain</h4>
<div id="outline-container-orgab936f6" class="outline-4">
<h4 id="orgab936f6"><span class="section-number-4">2.1.3</span> Time Domain</h4>
<div class="outline-text-4" id="text-2-1-3">
<p>
We compare the signal when the Slip-Ring is OFF (figure <a href="#org441e74d">4</a>) and when it is ON (figure <a href="#org3a186ee">5</a>).
We compare the signal when the Slip-Ring is OFF (figure <a href="#org85ec7c3">4</a>) and when it is ON (figure <a href="#orgbd68395">5</a>).
</p>
<div id="org441e74d" class="figure">
<div id="org85ec7c3" class="figure">
<p><img src="figs/sr_geophone_time_off.png" alt="sr_geophone_time_off.png" />
</p>
<p><span class="figure-number">Figure 4: </span>Comparison of the time domain signals when the slip-ring is OFF</p>
</div>
<div id="org3a186ee" class="figure">
<div id="orgbd68395" class="figure">
<p><img src="figs/sr_geophone_time_on.png" alt="sr_geophone_time_on.png" />
</p>
<p><span class="figure-number">Figure 5: </span>Comparison of the time domain signals when the slip-ring is ON</p>
@@ -716,8 +718,8 @@ We compare the signal when the Slip-Ring is OFF (figure <a href="#org441e74d">4<
</div>
</div>
<div id="outline-container-orgfb4b1b3" class="outline-4">
<h4 id="orgfb4b1b3"><span class="section-number-4">2.1.4</span> Frequency Domain</h4>
<div id="outline-container-orga860ebc" class="outline-4">
<h4 id="orga860ebc"><span class="section-number-4">2.1.4</span> Frequency Domain</h4>
<div class="outline-text-4" id="text-2-1-4">
<p>
We first compute some parameters that will be used for the PSD computation.
@@ -746,7 +748,7 @@ Then we compute the Power Spectral Density using <code>pwelch</code> function.
</div>
<p>
Finally, we compare the Amplitude Spectral Density of the signals (figure <a href="#org95029b1">6</a>);
Finally, we compare the Amplitude Spectral Density of the signals (figure <a href="#org5744581">6</a>);
</p>
<div class="org-src-container">
@@ -766,14 +768,14 @@ xlim<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-rainbo
</div>
<div id="org95029b1" class="figure">
<div id="org5744581" class="figure">
<p><img src="figs/sr_geophone_asd.png" alt="sr_geophone_asd.png" />
</p>
<p><span class="figure-number">Figure 6: </span>Comparison of the Amplitude Spectral Sensity</p>
</div>
<div id="org1cbbe97" class="figure">
<div id="org61603cc" class="figure">
<p><img src="figs/sr_geophone_asd_zoom.png" alt="sr_geophone_asd_zoom.png" />
</p>
<p><span class="figure-number">Figure 7: </span>Comparison of the Amplitude Spectral Sensity - Zoom</p>
@@ -781,8 +783,8 @@ xlim<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-rainbo
</div>
</div>
<div id="outline-container-org8df486d" class="outline-4">
<h4 id="org8df486d"><span class="section-number-4">2.1.5</span> Conclusion</h4>
<div id="outline-container-org2f13e1b" class="outline-4">
<h4 id="org2f13e1b"><span class="section-number-4">2.1.5</span> Conclusion</h4>
<div class="outline-text-4" id="text-2-1-5">
<div class="important">
<ul class="org-ul">
@@ -795,7 +797,7 @@ xlim<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-rainbo
<b>Questions</b>:
</p>
<ul class="org-ul">
<li>Can the sharp peak on figure <a href="#org1cbbe97">7</a> be due to the Aliasing?</li>
<li>Can the sharp peak on figure <a href="#org61603cc">7</a> be due to the Aliasing?</li>
</ul>
</div>
@@ -803,12 +805,12 @@ xlim<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-rainbo
</div>
</div>
<div id="outline-container-org5a500b8" class="outline-3">
<h3 id="org5a500b8"><span class="section-number-3">2.2</span> Measurement using an oscilloscope</h3>
<div id="outline-container-org09f7fe0" class="outline-3">
<h3 id="org09f7fe0"><span class="section-number-3">2.2</span> Measurement using an oscilloscope</h3>
<div class="outline-text-3" id="text-2-2">
</div>
<div id="outline-container-orgb213fc5" class="outline-4">
<h4 id="orgb213fc5"><span class="section-number-4">2.2.1</span> Measurement Setup</h4>
<div id="outline-container-org05d3686" class="outline-4">
<h4 id="org05d3686"><span class="section-number-4">2.2.1</span> Measurement Setup</h4>
<div class="outline-text-4" id="text-2-2-1">
<p>
We are now measuring the same signals than in the previous section, but with an oscilloscope instead of with the Speedgoat ADC.
@@ -816,26 +818,26 @@ We are now measuring the same signals than in the previous section, but with an
</div>
</div>
<div id="outline-container-orgc19f828" class="outline-4">
<h4 id="orgc19f828"><span class="section-number-4">2.2.2</span> Observations</h4>
<div id="outline-container-org31ccfad" class="outline-4">
<h4 id="org31ccfad"><span class="section-number-4">2.2.2</span> Observations</h4>
<div class="outline-text-4" id="text-2-2-2">
<p>
Then the Slip-Ring is ON (figure <a href="#org6d55390">8</a>), we observe a signal at 40kHz with a peak-to-peak amplitude of 200mV for the direct measure and 100mV for the signal going through the Slip-Ring.
Then the Slip-Ring is ON (figure <a href="#org233fc3b">8</a>), we observe a signal at 40kHz with a peak-to-peak amplitude of 200mV for the direct measure and 100mV for the signal going through the Slip-Ring.
</p>
<p>
Then the Slip-Ring is OFF, we don't observe this noise at 40kHz anymore (figure <a href="#org4e31dbe">9</a>).
Then the Slip-Ring is OFF, we don't observe this noise at 40kHz anymore (figure <a href="#org69c8279">9</a>).
</p>
<div id="org6d55390" class="figure">
<div id="org233fc3b" class="figure">
<p><img src="./img/IMG_20190506_160420.jpg" alt="IMG_20190506_160420.jpg" width="500px" />
</p>
<p><span class="figure-number">Figure 8: </span>Signals measured by the oscilloscope - Slip-Ring ON - Yellow: Direct measure - Blue: Through Slip-Ring</p>
</div>
<div id="org4e31dbe" class="figure">
<div id="org69c8279" class="figure">
<p><img src="./img/IMG_20190506_160438.jpg" alt="IMG_20190506_160438.jpg" width="500px" />
</p>
<p><span class="figure-number">Figure 9: </span>Signals measured by the oscilloscope - Slip-Ring OFF - Yellow: Direct measure - Blue: Through Slip-Ring</p>
@@ -843,8 +845,8 @@ Then the Slip-Ring is OFF, we don't observe this noise at 40kHz anymore (figure
</div>
</div>
<div id="outline-container-org61930e6" class="outline-4">
<h4 id="org61930e6"><span class="section-number-4">2.2.3</span> Conclusion</h4>
<div id="outline-container-org6b078b2" class="outline-4">
<h4 id="org6b078b2"><span class="section-number-4">2.2.3</span> Conclusion</h4>
<div class="outline-text-4" id="text-2-2-3">
<div class="important">
<ul class="org-ul">
@@ -858,12 +860,12 @@ Then the Slip-Ring is OFF, we don't observe this noise at 40kHz anymore (figure
</div>
</div>
<div id="outline-container-orgb00f95d" class="outline-3">
<h3 id="orgb00f95d"><span class="section-number-3">2.3</span> New measurements with a LPF before the Voltage Amplifiers</h3>
<div id="outline-container-org70c9bc1" class="outline-3">
<h3 id="org70c9bc1"><span class="section-number-3">2.3</span> New measurements with a LPF before the Voltage Amplifiers</h3>
<div class="outline-text-3" id="text-2-3">
</div>
<div id="outline-container-org9fa4c9c" class="outline-4">
<h4 id="org9fa4c9c"><span class="section-number-4">2.3.1</span> Setup description</h4>
<div id="outline-container-org64b7d09" class="outline-4">
<h4 id="org64b7d09"><span class="section-number-4">2.3.1</span> Setup description</h4>
<div class="outline-text-4" id="text-2-3-1">
<p>
<b>Goal</b>:
@@ -963,8 +965,8 @@ Each of the measurement <code>mat</code> file contains one <code>data</code> arr
</div>
</div>
<div id="outline-container-org56ffeb4" class="outline-4">
<h4 id="org56ffeb4"><span class="section-number-4">2.3.2</span> Load data</h4>
<div id="outline-container-org5426009" class="outline-4">
<h4 id="org5426009"><span class="section-number-4">2.3.2</span> Load data</h4>
<div class="outline-text-4" id="text-2-3-2">
<p>
We load the data of the z axis of two geophones.
@@ -977,22 +979,22 @@ sr_lpf_on = load<span class="org-rainbow-delimiters-depth-1">(</span><span clas
</div>
</div>
<div id="outline-container-orgcabd836" class="outline-4">
<h4 id="orgcabd836"><span class="section-number-4">2.3.3</span> Time Domain</h4>
<div id="outline-container-orgb76acbe" class="outline-4">
<h4 id="orgb76acbe"><span class="section-number-4">2.3.3</span> Time Domain</h4>
<div class="outline-text-4" id="text-2-3-3">
<p>
We compare the signal when the Slip-Ring is OFF (figure <a href="#org81b0ec6">10</a>) and when it is ON (figure <a href="#org677a685">11</a>).
We compare the signal when the Slip-Ring is OFF (figure <a href="#orge5ff08d">10</a>) and when it is ON (figure <a href="#org1ea0e78">11</a>).
</p>
<div id="org81b0ec6" class="figure">
<div id="orge5ff08d" class="figure">
<p><img src="figs/sr_lpf_geophone_time_off.png" alt="sr_lpf_geophone_time_off.png" />
</p>
<p><span class="figure-number">Figure 10: </span>Comparison of the time domain signals when the slip-ring is OFF</p>
</div>
<div id="org677a685" class="figure">
<div id="org1ea0e78" class="figure">
<p><img src="figs/sr_lpf_geophone_time_on.png" alt="sr_lpf_geophone_time_on.png" />
</p>
<p><span class="figure-number">Figure 11: </span>Comparison of the time domain signals when the slip-ring is ON</p>
@@ -1000,8 +1002,8 @@ We compare the signal when the Slip-Ring is OFF (figure <a href="#org81b0ec6">10
</div>
</div>
<div id="outline-container-org50b3d2c" class="outline-4">
<h4 id="org50b3d2c"><span class="section-number-4">2.3.4</span> Frequency Domain</h4>
<div id="outline-container-orgbef3f23" class="outline-4">
<h4 id="orgbef3f23"><span class="section-number-4">2.3.4</span> Frequency Domain</h4>
<div class="outline-text-4" id="text-2-3-4">
<p>
We first compute some parameters that will be used for the PSD computation.
@@ -1030,7 +1032,7 @@ Then we compute the Power Spectral Density using <code>pwelch</code> function.
</div>
<p>
Finally, we compare the Amplitude Spectral Density of the signals (figure <a href="#org3d43bfc">12</a>);
Finally, we compare the Amplitude Spectral Density of the signals (figure <a href="#org90a80c6">12</a>);
</p>
<div class="org-src-container">
@@ -1049,14 +1051,14 @@ legend<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-stri
</div>
<div id="org3d43bfc" class="figure">
<div id="org90a80c6" class="figure">
<p><img src="figs/sr_lpf_geophone_asd.png" alt="sr_lpf_geophone_asd.png" />
</p>
<p><span class="figure-number">Figure 12: </span>Comparison of the Amplitude Spectral Sensity</p>
</div>
<div id="org10ad34a" class="figure">
<div id="org98cd9ed" class="figure">
<p><img src="figs/sr_lpf_geophone_asd_zoom.png" alt="sr_lpf_geophone_asd_zoom.png" />
</p>
<p><span class="figure-number">Figure 13: </span>Comparison of the Amplitude Spectral Sensity - Zoom</p>
@@ -1064,8 +1066,8 @@ legend<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-stri
</div>
</div>
<div id="outline-container-org2a4f07d" class="outline-4">
<h4 id="org2a4f07d"><span class="section-number-4">2.3.5</span> Conclusion</h4>
<div id="outline-container-orgc1fcca7" class="outline-4">
<h4 id="orgc1fcca7"><span class="section-number-4">2.3.5</span> Conclusion</h4>
<div class="outline-text-4" id="text-2-3-5">
<div class="important">
<ul class="org-ul">
@@ -1079,12 +1081,12 @@ legend<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-stri
</div>
</div>
<div id="outline-container-orgd55b3f8" class="outline-3">
<h3 id="orgd55b3f8"><span class="section-number-3">2.4</span> Measurement of the noise induced by the slip-ring with additional LPF at 1kHz</h3>
<div id="outline-container-orga70c2df" class="outline-3">
<h3 id="orga70c2df"><span class="section-number-3">2.4</span> Measurement of the noise induced by the slip-ring with additional LPF at 1kHz</h3>
<div class="outline-text-3" id="text-2-4">
</div>
<div id="outline-container-org469d03f" class="outline-4">
<h4 id="org469d03f"><span class="section-number-4">2.4.1</span> Measurement description</h4>
<div id="outline-container-orgc629012" class="outline-4">
<h4 id="orgc629012"><span class="section-number-4">2.4.1</span> Measurement description</h4>
<div class="outline-text-4" id="text-2-4-1">
<p>
<b>Setup</b>:
@@ -1186,8 +1188,8 @@ Each of the measurement <code>mat</code> file contains one <code>data</code> arr
</div>
</div>
<div id="outline-container-org6bf316b" class="outline-4">
<h4 id="org6bf316b"><span class="section-number-4">2.4.2</span> Load data</h4>
<div id="outline-container-org04e8d20" class="outline-4">
<h4 id="org04e8d20"><span class="section-number-4">2.4.2</span> Load data</h4>
<div class="outline-text-4" id="text-2-4-2">
<p>
We load the data of the z axis of two geophones.
@@ -1200,22 +1202,44 @@ sr_lpf_1khz_on = load<span class="org-rainbow-delimiters-depth-1">(</span><span
</div>
</div>
<div id="outline-container-orga099a0e" class="outline-4">
<h4 id="orga099a0e"><span class="section-number-4">2.4.3</span> Time Domain</h4>
<div id="outline-container-org8394ea8" class="outline-4">
<h4 id="org8394ea8"><span class="section-number-4">2.4.3</span> Pre-processing</h4>
<div class="outline-text-4" id="text-2-4-3">
<p>
We compare the signal when the Slip-Ring is OFF (figure <a href="#orga7f22df">14</a>) and when it is ON (figure <a href="#org33a10ec">15</a>).
There is a sign difference between the signal going directly to the ADC and the signal going through the slip-ring. We add a minus sign on the signal going through the slip-ring.
</p>
<p>
We also subtract the mean value as the voltage amplifiers were on the DC option.
</p>
<div class="org-src-container">
<pre class="src src-matlab">sr_lpf_1khz_of<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-1">)</span> = sr_lpf_1khz_of<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-1">)</span><span class="org-type">-</span>mean<span class="org-rainbow-delimiters-depth-1">(</span>sr_lpf_1khz_of<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><span class="org-rainbow-delimiters-depth-1">)</span>;
sr_lpf_1khz_of<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">2</span><span class="org-rainbow-delimiters-depth-1">)</span> = <span class="org-type">-</span><span class="org-rainbow-delimiters-depth-1">(</span>sr_lpf_1khz_of<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><span class="org-type">-</span>mean<span class="org-rainbow-delimiters-depth-2">(</span>sr_lpf_1khz_of<span class="org-rainbow-delimiters-depth-3">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">2</span><span class="org-rainbow-delimiters-depth-3">)</span><span class="org-rainbow-delimiters-depth-2">)</span><span class="org-rainbow-delimiters-depth-1">)</span>;
sr_lpf_1khz_on<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-1">)</span> = sr_lpf_1khz_on<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">1</span><span class="org-rainbow-delimiters-depth-1">)</span><span class="org-type">-</span>mean<span class="org-rainbow-delimiters-depth-1">(</span>sr_lpf_1khz_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><span class="org-rainbow-delimiters-depth-1">)</span>;
sr_lpf_1khz_on<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">2</span><span class="org-rainbow-delimiters-depth-1">)</span> = <span class="org-type">-</span><span class="org-rainbow-delimiters-depth-1">(</span>sr_lpf_1khz_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><span class="org-type">-</span>mean<span class="org-rainbow-delimiters-depth-2">(</span>sr_lpf_1khz_on<span class="org-rainbow-delimiters-depth-3">(</span><span class="org-type">:</span>, <span class="org-highlight-numbers-number">2</span><span class="org-rainbow-delimiters-depth-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-orgd37877e" class="outline-4">
<h4 id="orgd37877e"><span class="section-number-4">2.4.4</span> Time Domain</h4>
<div class="outline-text-4" id="text-2-4-4">
<p>
We compare the signal when the Slip-Ring is OFF (figure <a href="#orga139aa7">14</a>) and when it is ON (figure <a href="#orgd1e1d23">15</a>).
</p>
<div id="orga7f22df" class="figure">
<div id="orga139aa7" class="figure">
<p><img src="figs/sr_lpf_1khz_geophone_time_off.png" alt="sr_lpf_1khz_geophone_time_off.png" />
</p>
<p><span class="figure-number">Figure 14: </span>Comparison of the time domain signals when the slip-ring is OFF</p>
</div>
<div id="org33a10ec" class="figure">
<div id="orgd1e1d23" class="figure">
<p><img src="figs/sr_lpf_1khz_geophone_time_on.png" alt="sr_lpf_1khz_geophone_time_on.png" />
</p>
<p><span class="figure-number">Figure 15: </span>Comparison of the time domain signals when the slip-ring is ON</p>
@@ -1223,9 +1247,9 @@ We compare the signal when the Slip-Ring is OFF (figure <a href="#orga7f22df">14
</div>
</div>
<div id="outline-container-org879b6b3" class="outline-4">
<h4 id="org879b6b3"><span class="section-number-4">2.4.4</span> Frequency Domain</h4>
<div class="outline-text-4" id="text-2-4-4">
<div id="outline-container-orgc77f23c" class="outline-4">
<h4 id="orgc77f23c"><span class="section-number-4">2.4.5</span> Frequency Domain</h4>
<div class="outline-text-4" id="text-2-4-5">
<p>
We first compute some parameters that will be used for the PSD computation.
</p>
@@ -1253,7 +1277,7 @@ Then we compute the Power Spectral Density using <code>pwelch</code> function.
</div>
<p>
Finally, we compare the Amplitude Spectral Density of the signals (figure <a href="#orgb2f9278">16</a>);
Finally, we compare the Amplitude Spectral Density of the signals (figure <a href="#org5c47e51">16</a>);
</p>
<div class="org-src-container">
@@ -1264,7 +1288,7 @@ plot<span class="org-rainbow-delimiters-depth-1">(</span>f, sqrt<span class="org
plot<span class="org-rainbow-delimiters-depth-1">(</span>f, sqrt<span class="org-rainbow-delimiters-depth-2">(</span>pxdi_lpf_1khz_on<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>pxsr_lpf_1khz_on<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;
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>;
xlim<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-rainbow-delimiters-depth-2">[</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>;
<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-string"><span class="org-rainbow-delimiters-depth-1">)</span></span><span class="org-string">; set</span><span class="org-string"><span class="org-rainbow-delimiters-depth-1">(</span></span><span class="org-string">gca, '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', 'southwest'</span><span class="org-rainbow-delimiters-depth-1">)</span>;
@@ -1272,7 +1296,7 @@ legend<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-stri
</div>
<div id="orgb2f9278" class="figure">
<div id="org5c47e51" class="figure">
<p><img src="figs/sr_lpf_1khz_geophone_asd.png" alt="sr_lpf_1khz_geophone_asd.png" />
</p>
<p><span class="figure-number">Figure 16: </span>Comparison of the Amplitude Spectral Sensity</p>
@@ -1280,13 +1304,46 @@ legend<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-stri
</div>
</div>
<div id="outline-container-orgc1bf114" class="outline-4">
<h4 id="orgc1bf114"><span class="section-number-4">2.4.5</span> Conclusion</h4>
<div class="outline-text-4" id="text-2-4-5">
<div id="outline-container-org92d0230" class="outline-4">
<h4 id="org92d0230"><span class="section-number-4">2.4.6</span> Difference between the direct signal and the signal going through the slip-ring</h4>
<div class="outline-text-4" id="text-2-4-6">
<p>
We subtract the signal coming from the direct wire to the signal going through the slip-ring when the slip-ring is ON and when it is OFF (figure <a href="#org5cffaa8">17</a>).
</p>
<div id="org5cffaa8" class="figure">
<p><img src="figs/diff_sr_direct.png" alt="diff_sr_direct.png" />
</p>
<p><span class="figure-number">Figure 17: </span>Difference between the signal going directly to the ADC and the signal going through the slip-ring before the ADC</p>
</div>
<p>
Then we compute the Power Spectral Density using <code>pwelch</code> function (figure <a href="#orgc534526">18</a>).
</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>px_diff_lpf_1khz_of, f<span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>sr_lpf_1khz_of<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><span class="org-type">-</span>sr_lpf_1khz_of<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>px_diff_lpf_1khz_on, <span class="org-type">~</span><span class="org-rainbow-delimiters-depth-1">]</span> = pwelch<span class="org-rainbow-delimiters-depth-1">(</span>sr_lpf_1khz_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><span class="org-type">-</span>sr_lpf_1khz_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>
<div id="orgc534526" class="figure">
<p><img src="figs/diff_sr_direct_psd.png" alt="diff_sr_direct_psd.png" />
</p>
<p><span class="figure-number">Figure 18: </span>Amplitude Spectral Density of the difference between the signal going directly to the ADC and the signal going through the slip-ring before the ADC</p>
</div>
</div>
</div>
<div id="outline-container-orga9ca1a2" class="outline-4">
<h4 id="orga9ca1a2"><span class="section-number-4">2.4.7</span> Conclusion</h4>
<div class="outline-text-4" id="text-2-4-7">
<div class="important">
<ul class="org-ul">
<li>Using the LPF, we don't see any additional noise coming from the slip-ring when it is turned ON</li>
<li>We here observe a signal at \(50Hz\) and its harmonics</li>
<li>The signal going through the slip-ring only differs from the direct signal by some 50Hz and its harmonics</li>
</ul>
</div>
@@ -1297,7 +1354,7 @@ legend<span class="org-rainbow-delimiters-depth-1">(</span><span class="org-stri
</div>
<div id="postamble" class="status">
<p class="author">Author: Dehaeze Thomas</p>
<p class="date">Created: 2019-05-16 jeu. 13:39</p>
<p class="date">Created: 2019-05-17 ven. 10:04</p>
<p class="validation"><a href="http://validator.w3.org/check?uri=referer">Validate</a></p>
</div>
</body>