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<div class="refentry" title="poscil">
<a id="poscil"></a>
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<h2>
<span class="refentrytitle">poscil</span>
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<p>poscil —
High precision oscillator.
</p>
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<div class="refsect1" title="Description">
<a id="id3109841"></a>
<h2>Description</h2>
<p>
High precision oscillator.
</p>
</div>
<div class="refsect1" title="Syntax">
<a id="id3109853"></a>
<h2>Syntax</h2>
<pre class="synopsis">ares <span class="command"><strong>poscil</strong></span> aamp, acps, ifn [, iphs]</pre>
<pre class="synopsis">ares <span class="command"><strong>poscil</strong></span> aamp, kcps, ifn [, iphs]</pre>
<pre class="synopsis">ares <span class="command"><strong>poscil</strong></span> kamp, acps, ifn [, iphs]</pre>
<pre class="synopsis">ares <span class="command"><strong>poscil</strong></span> kamp, kcps, ifn [, iphs]</pre>
<pre class="synopsis">ires <span class="command"><strong>poscil</strong></span> kamp, kcps, ifn [, iphs]</pre>
<pre class="synopsis">kres <span class="command"><strong>poscil</strong></span> kamp, kcps, ifn [, iphs]</pre>
</div>
<div class="refsect1" title="Initialization">
<a id="id3110779"></a>
<h2>Initialization</h2>
<p>
<span class="emphasis"><em>ifn</em></span> -- function table number
</p>
<p>
<span class="emphasis"><em>iphs</em></span> (optional, default=0) -- initial phase (normalized table index 0-1)
</p>
</div>
<div class="refsect1" title="Performance">
<a id="id3110803"></a>
<h2>Performance</h2>
<p>
<span class="emphasis"><em>ares</em></span> -- output signal
</p>
<p>
<span class="emphasis"><em>kamp</em></span>, <span class="emphasis"><em>aamp</em></span> -- the amplitude of the output signal.
</p>
<p>
<span class="emphasis"><em>kcps</em></span>, <span class="emphasis"><em>acps</em></span> -- the frequency of the output signal in cycles per second.
</p>
<p>
<span class="emphasis"><em>poscil</em></span> (precise oscillator) is the same as <a class="link" href="oscili.html" title="oscili"><em class="citetitle">oscili</em></a>, but allows much more precise frequency control, especially when using long tables and low frequency values. It uses floating-point table indexing, instead of integer math, like <span class="emphasis"><em>oscil</em></span> and <span class="emphasis"><em>oscili</em></span>. It is only a bit slower than <span class="emphasis"><em>oscili</em></span>.
</p>
<p>
Since Csound 4.22, <span class="emphasis"><em>poscil</em></span> can accept also negative frequency values and use a-rate values both for amplitude and frequency. So both AM and FM are allowed using this opcode.
</p>
<p>The opcode <a class="link" href="poscil3.html" title="poscil3"><em class="citetitle">poscil3</em></a> is the same as <span class="emphasis"><em>poscil</em></span>, but uses cubic interpolation.</p>
<p>Note that <span class="emphasis"><em>poscil</em></span> can use deffered (non-power of two) length tables.</p>
</div>
<div class="refsect1" title="Examples">
<a id="id3110908"></a>
<h2>Examples</h2>
<p>
Here is an example of the poscil opcode. It uses the file <a class="ulink" href="examples/poscil.csd" target="_top"><em class="citetitle">poscil.csd</em></a>.
</p>
<div class="example">
<a id="id3110924"></a>
<p class="title">
<b>Example 447. Example of the poscil 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 poscil.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 - a basic oscillator.</span>
<span class="oblock">instr</span> 1
kamp <span class="op">=</span> 10000
kcps <span class="op">=</span> 440
ifn <span class="op">=</span> 1
a1 <span class="opc">poscil</span> kamp, kcps, ifn
<span class="opc">out</span> a1
<span class="oblock">endin</span>
<span class="csdtag"></CsInstruments></span>
<span class="csdtag"><CsScore></span>
<span class="comment">; Table #1, a sine wave.</span>
<span class="stamnt">f</span> 1 0 16384 10 1
<span class="comment">; Play Instrument #1 for 2 seconds.</span>
<span class="stamnt">i</span> 1 0 2
<span class="stamnt">e</span>
<span class="csdtag"></CsScore></span>
<span class="csdtag"></CsoundSynthesizer></span>
</pre>
</div>
</div>
<p><br class="example-break" />
</p>
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<div class="refsect1" title="See Also">
<a id="id3110962"></a>
<h2>See Also</h2>
<p>
<a class="link" href="poscil3.html" title="poscil3"><em class="citetitle">poscil3</em></a>
</p>
</div>
<div class="refsect1" title="Credits">
<a id="id3110979"></a>
<h2>Credits</h2>
<p>
</p>
<table border="0" summary="Simple list" class="simplelist">
<tr>
<td>Author: Gabriel Maldonado</td>
</tr>
<tr>
<td>Italy</td>
</tr>
<tr>
<td>1998</td>
</tr>
</table>
<p>
</p>
<p>Example written by Kevin Conder.</p>
<p>November 2002. Added a note about the changes to Csound version 4.22, thanks to Rasmus Ekman.</p>
<p>New in Csound version 3.52</p>
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