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<div class="title">Variance Example</div>  </div>
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<dl class="section user"><dt>Description:</dt><dd></dd></dl>
<dl class="section user"><dt></dt><dd>Demonstrates the use of Basic Math and Support Functions to calculate the variance of an input sequence with N samples. Uniformly distributed white noise is taken as input.</dd></dl>
<dl class="section user"><dt>Algorithm:</dt><dd></dd></dl>
<dl class="section user"><dt></dt><dd>The variance of a sequence is the mean of the squared deviation of the sequence from its mean. </dd></dl>
<dl class="section user"><dt></dt><dd>This is denoted by the following equation: <pre> variance = ((x[0] - x') * (x[0] - x') + (x[1] - x') * (x[1] - x') + ... + * (x[n-1] - x') * (x[n-1] - x')) / (N-1)</pre> where, <code>x[n]</code> is the input sequence, <code>N</code> is the number of input samples, and <code>x'</code> is the mean value of the input sequence, <code>x[n]</code>. </dd></dl>
<dl class="section user"><dt></dt><dd>The mean value <code>x'</code> is defined as: <pre> x' = (x[0] + x[1] + ... + x[n-1]) / N</pre></dd></dl>
<dl class="section user"><dt>Block Diagram:</dt><dd></dd></dl>
<dl class="section user"><dt></dt><dd><div class="image">
<img src="Variance.gif" alt="Variance.gif"/>
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</dd></dl>
<dl class="section user"><dt>Variables Description:</dt><dd></dd></dl>
<dl class="section user"><dt></dt><dd><ul>
<li><code>testInput_f32</code> points to the input data </li>
<li><code>wire1</code>, <code>wir2</code>, <code>wire3</code> temporary buffers </li>
<li><code>blockSize</code> number of samples processed at a time </li>
<li><code>refVarianceOut</code> reference variance value</li>
</ul>
</dd></dl>
<dl class="section user"><dt>CMSIS DSP Software Library Functions Used:</dt><dd></dd></dl>
<dl class="section user"><dt></dt><dd><ul>
<li><a class="el" href="group__dot__prod.html#ga55418d4362f6ba84c327f9b4f089a8c3" title="Dot product of floating-point vectors.">arm_dot_prod_f32()</a></li>
<li><a class="el" href="group___basic_mult.html#gaca3f0b8227da431ab29225b88888aa32" title="Floating-point vector multiplication.">arm_mult_f32()</a></li>
<li><a class="el" href="group___basic_sub.html#ga7f975a472de286331134227c08aad826" title="Floating-point vector subtraction.">arm_sub_f32()</a></li>
<li><a class="el" href="group___fill.html#ga2248e8d3901b4afb7827163132baad94" title="Fills a constant value into a floating-point vector.">arm_fill_f32()</a></li>
<li><a class="el" href="group__copy.html#gadd1f737e677e0e6ca31767c7001417b3" title="Copies the elements of a floating-point vector.">arm_copy_f32()</a></li>
</ul>
</dd></dl>
<p><b> Refer </b> <a class="el" href="arm_variance_example_f32_8c-example.html">arm_variance_example_f32.c</a> </p>
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