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<h2>
<span class="refentrytitle">trfilter</span>
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<p>trfilter —
Streaming partial track filtering.
</p>
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<div class="refsect1" title="Description">
<a id="id3300354"></a>
<h2>Description</h2>
<p>
The trfilter opcode takes an input containg a TRACKS pv streaming signal (as generated,
for instance by partials) and filters it using an amplitude response curve stored in
a function table. The function table can have any size (no restriction to powers-of-two).
The table lookup is done by linear-interpolation. It is possible to create time-varying
filter curves by updating the amlitude response table with a table-writing opcode.
</p>
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<div class="refsect1" title="Syntax">
<a id="id3300372"></a>
<h2>Syntax</h2>
<pre class="synopsis">fsig <span class="command"><strong>trfilter</strong></span> fin, kamnt, ifn</pre>
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<div class="refsect1" title="Performance">
<a id="id3300389"></a>
<h2>Performance</h2>
<p>
<span class="emphasis"><em>fsig</em></span> -- output pv stream in TRACKS format
</p>
<p>
<span class="emphasis"><em>fin</em></span> -- input pv stream in TRACKS format
</p>
<p>
<span class="emphasis"><em>kamnt</em></span> -- amount of filtering (0-1)
</p>
<p>
<span class="emphasis"><em>ifn</em></span> -- function table number. This will contain an
amplitude response curve, from 0 Hz to the Nyquist (table indexes 0 to N). Any size is
allowed. Larger tables will provide a smoother amplitude response curve. Table reading uses
linear interpolation.
</p>
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<div class="refsect1" title="Examples">
<a id="id3301223"></a>
<h2>Examples</h2>
<p>
</p>
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<a id="id3301231"></a>
<p class="title">
<b>Example 633. Example</b>
</p>
<div class="example-contents">
<pre class="programlisting">
gifn ftgen 2, 0, -22050, 5 1 1000 1 4000 0.000001 17050 0.000001 ; low-pass filter curve of 22050 points
instr 1
ain inch 1 ; input signal
fs1,fsi2 pvsifd ain,2048,512,1 ; ifd analysis
fst partials fs1,fsi2,.003,1,3,500 ; partial tracking
fscl trfilter fst, 1, gifn ; filtering using function table 2
aout tradsyn fscl, 1, 1, 500, 1 ; resynthesis
out aout
endin
</pre>
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</div>
<p><br class="example-break" />
</p>
<p>
The example above shows partial tracking of an ifd-analysis signal and
linear additive resynthesis with low-pass filtering.
</p>
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<div class="refsect1" title="Credits">
<a id="id3301258"></a>
<h2>Credits</h2>
<p>
</p>
<table border="0" summary="Simple list" class="simplelist">
<tr>
<td>Author: Victor Lazzarini;</td>
</tr>
<tr>
<td>February 2006 </td>
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<p>New in Csound5.01</p>
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