title: plot rectangular pulse in matlab
body: <p>I'm trying to plot rectangular pulse in matlab but unfortunately I receive this message error:</p>
  
  <pre><code>T=sym('T','real');
  &gt;&gt; t=-5*T:1/2*T:5*T; 
  &gt;&gt; y=5*rectpuls(t,T);
  ??? Error using ==&gt; sym.sym&gt;notimplemented at 2621
      Function 'lt' is not implemented for MuPAD symbolic objects.
  
      Error in ==&gt; sym.sym&gt;sym.lt at 812
          notimplemented('lt');
  
      Error in ==&gt; rectpuls at 22
      y = abs(t)&lt;Tw/2-eps;
  </code></pre>
  
  <p>which could be the mistake?</p>