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<div class="refentry" title="lfo">
<a id="lfo"></a>
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<a id="Indexlfo" class="indexterm"></a>
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<h2>
<span class="refentrytitle">lfo</span>
</h2>
<p>lfo —
A low frequency oscillator of various shapes.
</p>
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<div class="refsect1" title="Description">
<a id="id2980579"></a>
<h2>Description</h2>
<p>
A low frequency oscillator of various shapes.
</p>
</div>
<div class="refsect1" title="Syntax">
<a id="id2980591"></a>
<h2>Syntax</h2>
<pre class="synopsis">kres <span class="command"><strong>lfo</strong></span> kamp, kcps [, itype]</pre>
<pre class="synopsis">ares <span class="command"><strong>lfo</strong></span> kamp, kcps [, itype]</pre>
</div>
<div class="refsect1" title="Initialization">
<a id="id2980927"></a>
<h2>Initialization</h2>
<p>
<span class="emphasis"><em>itype</em></span> (optional, default=0) -- determine the waveform of the oscillator. Default is 0.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" type="disc">
<li class="listitem">
<p><span class="emphasis"><em>itype</em></span> = 0 - sine</p>
</li>
<li class="listitem">
<p><span class="emphasis"><em>itype</em></span> = 1 - triangles</p>
</li>
<li class="listitem">
<p><span class="emphasis"><em>itype</em></span> = 2 - square (bipolar)</p>
</li>
<li class="listitem">
<p><span class="emphasis"><em>itype</em></span> = 3 - square (unipolar)</p>
</li>
<li class="listitem">
<p><span class="emphasis"><em>itype</em></span> = 4 - saw-tooth</p>
</li>
<li class="listitem">
<p><span class="emphasis"><em>itype</em></span> = 5 - saw-tooth(down)</p>
</li>
</ul>
</div>
<p>
</p>
<p>
The sine wave is implemented as a 4096 table and linear interpolation. The others are calculated.
</p>
</div>
<div class="refsect1" title="Performance">
<a id="id2981366"></a>
<h2>Performance</h2>
<p>
<span class="emphasis"><em>kamp</em></span> -- amplitude of output
</p>
<p>
<span class="emphasis"><em>kcps</em></span> -- frequency of oscillator
</p>
</div>
<div class="refsect1" title="Examples">
<a id="id2981389"></a>
<h2>Examples</h2>
<p>
Here is an example of the lfo opcode. It uses the file <a class="ulink" href="examples/lfo.csd" target="_top"><em class="citetitle">lfo.csd</em></a>.
</p>
<div class="example">
<a id="id2981405"></a>
<p class="title">
<b>Example 331. Example of the lfo opcode.</b>
</p>
<div class="example-contents">
<p>See the sections <a class="link" href="UsingRealTime.html" title="Real-Time Audio"><em class="citetitle">Real-time Audio</em></a> and <a class="link" href="CommandFlags.html" title="Csound command line"><em class="citetitle">Command Line Flags</em></a> for more information on using command line flags.</p>
<pre class="programlisting">
<span class="csdtag"><CsoundSynthesizer></span>
<span class="csdtag"><CsOptions></span>
<span class="comment">; Select audio/midi flags here according to platform</span>
<span class="comment">; Audio out Audio in No messages</span>
-odac -iadc -d <span class="comment">;;;RT audio I/O</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o lfo.wav -W ;;; for file output any platform</span>
<span class="csdtag"></CsOptions></span>
<span class="csdtag"><CsInstruments></span>
<span class="comment">; Initialize the global variables.</span>
<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">kr</span> <span class="op">=</span> 4410
<span class="ohdr">ksmps</span> <span class="op">=</span> 10
<span class="ohdr">nchnls</span> <span class="op">=</span> 1
<span class="comment">; Instrument #1.</span>
<span class="oblock">instr</span> 1
kamp <span class="op">=</span> 10
kcps <span class="op">=</span> 5
itype <span class="op">=</span> 4
k1 <span class="opc">lfo</span> kamp, kcps, itype
ar <span class="opc">oscil</span> p4, p5<span class="op">+</span>k1, 1
<span class="opc">out</span> ar
<span class="oblock">endin</span>
<span class="csdtag"></CsInstruments></span>
<span class="csdtag"><CsScore></span>
<span class="comment">; Table #1: an ordinary sine wave.</span>
<span class="stamnt">f</span> 1 0 32768 10 1
<span class="comment">; p4 = amplitude of the output signal.</span>
<span class="comment">; p5 = frequency (in cycles per second) of the output signal.</span>
<span class="comment">; Play Instrument #1 for two seconds.</span>
<span class="stamnt">i</span> 1 0 2 10000 220
<span class="stamnt">e</span>
<span class="csdtag"></CsScore></span>
<span class="csdtag"></CsoundSynthesizer></span>
</pre>
</div>
</div>
<p><br class="example-break" />
</p>
</div>
<div class="refsect1" title="Credits">
<a id="id2981443"></a>
<h2>Credits</h2>
<p>
</p>
<table border="0" summary="Simple list" class="simplelist">
<tr>
<td>Author: John ffitch</td>
</tr>
<tr>
<td>University of Bath/Codemist Ltd.</td>
</tr>
<tr>
<td>Bath, UK</td>
</tr>
<tr>
<td>November 1998</td>
</tr>
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<p>
</p>
<p>New in Csound version 3.491</p>
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