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<span class="path"><a href="index.html">FOSSEE Signal Processing Toolbox</a> >> <a href="section_e54aa8aac34aa55341e8b4b782fe1a74.html">FOSSEE Signal Processing Toolbox</a> > stft</span>
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<div class="refnamediv"><h1 class="refname">stft</h1>
<p class="refpurpose">Compute the short-time Fourier transform of the vector X</p></div>
<div class="refsynopsisdiv"><h3 class="title">Calling Sequence</h3>
<div class="synopsis"><pre><span class="default">Y</span><span class="default"> = </span><span class="functionid">stft</span><span class="default"> (</span><span class="default">X</span><span class="default">)</span>
<span class="default">Y</span><span class="default"> = </span><span class="functionid">stft</span><span class="default"> (</span><span class="default">X</span><span class="default">, </span><span class="default">WIN_SIZE</span><span class="default">)</span>
<span class="default">Y</span><span class="default"> = </span><span class="functionid">stft</span><span class="default"> (</span><span class="default">X</span><span class="default">, </span><span class="default">WIN_SIZE</span><span class="default">, </span><span class="default">INC</span><span class="default">)</span>
<span class="default">Y</span><span class="default"> = </span><span class="functionid">stft</span><span class="default"> (</span><span class="default">X</span><span class="default">, </span><span class="default">WIN_SIZE</span><span class="default">, </span><span class="default">INC</span><span class="default">, </span><span class="default">NUM_COEF</span><span class="default">)</span>
<span class="default">Y</span><span class="default"> = </span><span class="functionid">stft</span><span class="default"> (</span><span class="default">X</span><span class="default">, </span><span class="default">WIN_SIZE</span><span class="default">, </span><span class="default">INC</span><span class="default">, </span><span class="default">NUM_COEF</span><span class="default">, </span><span class="default">WIN_TYPE</span><span class="default">)</span>
<span class="default">[</span><span class="default">Y</span><span class="default">,</span><span class="default">C</span><span class="default">] = </span><span class="functionid">stft</span><span class="default"> (</span><span class="default">X</span><span class="default">)</span>
<span class="default">[</span><span class="default">Y</span><span class="default">,</span><span class="default">C</span><span class="default">] = </span><span class="functionid">stft</span><span class="default"> (</span><span class="default">X</span><span class="default">, </span><span class="default">WIN_SIZE</span><span class="default">)</span>
<span class="default">[</span><span class="default">Y</span><span class="default">,</span><span class="default">C</span><span class="default">] = </span><span class="functionid">stft</span><span class="default"> (</span><span class="default">X</span><span class="default">, </span><span class="default">WIN_SIZE</span><span class="default">, </span><span class="default">INC</span><span class="default">)</span>
<span class="default">[</span><span class="default">Y</span><span class="default">,</span><span class="default">C</span><span class="default">] = </span><span class="functionid">stft</span><span class="default"> (</span><span class="default">X</span><span class="default">, </span><span class="default">WIN_SIZE</span><span class="default">, </span><span class="default">INC</span><span class="default">, </span><span class="default">NUM_COEF</span><span class="default">)</span>
<span class="default">[</span><span class="default">Y</span><span class="default">,</span><span class="default">C</span><span class="default">] = </span><span class="functionid">stft</span><span class="default"> (</span><span class="default">X</span><span class="default">, </span><span class="default">WIN_SIZE</span><span class="default">, </span><span class="default">INC</span><span class="default">, </span><span class="default">NUM_COEF</span><span class="default">, </span><span class="default">WIN_TYPE</span><span class="default">)</span></pre></div></div>
<div class="refsection"><h3 class="title">Parameters</h3>
<dl><dt><span class="term">X:</span>
<dd><p class="para">Real scalar or vector</p></dd></dt>
<dt><span class="term">WIN_SIZE:</span>
<dd><p class="para">Size of the window used</p></dd></dt>
<dt><span class="term">INC:</span>
<dd><p class="para">Increment</p></dd></dt>
<dt><span class="term">WIN_TYPE:</span>
<dd><p class="para">Type of window</p></dd></dt></dl></div>
<div class="refsection"><h3 class="title">Description</h3>
<p class="para">Compute the short-time Fourier transform of the vector X with NUM_COEF coefficients by applying a window of WIN_SIZE data points and an increment of INC points.</p>
<p class="para">Before computing the Fourier transform, one of the following windows is applied:</p>
<p class="para">"hanning" -> win_type = 1</p>
<p class="para">"hamming" -> win_type = 2</p>
<p class="para">"rectangle" -> win_type = 3</p>
<p class="para">The window names can be passed as strings or by the WIN_TYPE number.</p>
<p class="para">The following defaults are used for unspecified arguments:WIN_SIZE= 80, INC = 24, NUM_COEF = 64, and WIN_TYPE = 1.</p>
<p class="para">Y = stft (X, ...)' returns the absolute values of the Fourier coefficients according to the NUM_COEF positive frequencies.</p>
<p class="para">'[Y, C] = stft (x, ...)' returns the entire STFT-matrix Y and a 3-element vector C containing the window size, increment, and window type, which is needed by the 'synthesis' function.</p></div>
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