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61 lines
2.4 KiB
61 lines
2.4 KiB
<script type="text/x-red" data-help-name="AudioFilterStateVariable">
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<h3>Summary</h3>
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<div class=tooltipinfo>
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<p>A State Variable (Chamberlin) Filter with 12 dB/octave roll-off,
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adjustable resonance, and optional signal control of corner
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frequency.</p>
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</div>
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<h3>Audio Connections</h3>
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<table class=doc align=center cellpadding=3>
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<tr class=top><th>Port</th><th>Purpose</th></tr>
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<tr class=odd><td align=center>In 0</td><td>Signal to Filter</td></tr>
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<tr class=odd><td align=center>In 1</td><td>Frequency Control</td></tr>
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<tr class=odd><td align=center>Out 0</td><td>Low Pass Output</td></tr>
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<tr class=odd><td align=center>Out 1</td><td>Band Pass Output</td></tr>
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<tr class=odd><td align=center>Out 2</td><td>High Pass Output</td></tr>
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</table>
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<h3>Functions</h3>
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<p class=func><span class=keyword>frequency</span>(freq);</p>
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<p class=desc>Set the filter's corner frequency. When a signal is
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connected to the control input, the filter will implement this
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frequency when the signal is zero.
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</p>
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<p class=func><span class=keyword>resonance</span>(Q);</p>
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<p class=desc>Set the filter's resonance. Q ranges from 0.7 to 5.0.
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Resonance greater than 0.707 will amplify the signal near the
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corner frequency. You must attenuate the signal before input
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to this filter, to prevent clipping.
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</p>
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<p class=func><span class=keyword>octaveControl</span>(octaves);</p>
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<p class=desc>Set how much (in octaves) the control signal can alter
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the filter's corner freqency. Range is 0 to 7 octaves. For
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example, when set to 2.5, a full scale positive signal (1.0) will
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shift the filter frequency up 2.5 octaves, and a full scale negative
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signal will shift it down 2.5 octaves.
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</p>
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<!--
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<h3>Examples</h3>
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<p class=exam>File > Examples > Audio >
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</p>
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-->
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<h3>Notes</h3>
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<p>
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When controlled by a signal, the equation for the filter
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frequency is:
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</p>
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<p>
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F = Fcenter * 2^<sup>(signal * octaves)</sup>
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<br><small>If anyone knows how to do HTML equations, please
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help me improve this.....</small>
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</p>
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<p>When operating with signal control of corner frequency, this
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object uses approximately 4% of the CPU time on Teensy 3.1.
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</p>
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</script>
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<script type="text/x-red" data-template-name="AudioFilterFIR">
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<div class="form-row">
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<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>
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<input type="text" id="node-input-name" placeholder="Name">
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</div>
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</script>
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