pan class="keyword">if</span> acq.deriv
0149       [s, t, f] = mtspecgramc(abs(diff(data)), acq.moving_window, acq.params );
0150     <span class="keyword">else</span>
0151       [s, t, f] = mtspecgramc(diff(data), acq.moving_window, acq.params );
0152     <span class="keyword">end</span>
0153     
0154     <span class="comment">% Add new spectra to that already calculated</span>
0155     acq.times = [acq.times t+calctime];
0156     <span class="keyword">if</span> acq.log
0157         acq.spectra = [acq.spe