&gt;P),  error(<span class="string">'Requested start frame does not exist.'</span>);  <span class="keyword">end</span>;
0075 <span class="keyword">if</span> (Fs&lt;=0),               error(<span class="string">'Sampling rate must be positive.'</span>); <span class="keyword">end</span>;
0076 
0077 <span class="keyword">if</span> (~isreal(data)),  error(<span class="string">'DATA must be real'</span>);   <span class="comment">% get data limits</span>
0078 <span class="keyword">elseif</span>  (isa(data, <span 