   r: top-half of the auto-correlation coefficients</span>
<span class="comment">%      starts from 0th element to end of the auto-corelation</span>
<span class="comment">%      should be passed in as a column vector</span>
<span class="comment">% Output</span>
<span class="comment">%   h: impulse response that gives the desired auto-correlation</span>

<span class="keyword">function</span> h = spectral_fact(r)

<span class="comment">% length of the impulse response sequence</span>
n = length(r);

<span cla