)] from F[x(n)], that is constructs the 
FFT of the sine tapered signal.</p>
<p>The FFT should be performed previous to the call.</p>
<p><strong>Parameters</strong></p>
<dl class="simple">
<dt>nptwo<span class="classifier">float</span></dt><dd><p>The twice signal length (2*npts)</p>
</dd>
<dt>fx<span class="classifier">ndarray, complex [nptwo,2]             </span></dt><dd><p>The FFT of the two signals (twice length)</p>
</dd>
<dt>nf<span class="classifier">int</span></dt><dd><p>Number of frequency points f