p>A CLM instrument to produce this is:
</p>

<!-- CLM CASE
<pre class="indented">
(definstrument fm (beg end freq amp mc-ratios indexes carrier-phase mod-phases)
  (let* ((cr (make-oscil freq carrier-phase))
         (n (length mc-ratios))
         (md-arr (make-array n :element-type 'osc))
         (fm-index-arr (make-array n :element-type 'short-float)))
    (loop for i from 0 below n do
      (setf (aref md-arr i)
        (make-oscil (* freq (aref mc-ratios i)) 
                    (aref mod-phases i)))
