A first stage of the interpolation circuit calculates a one half amplitude value; {HEAD ~ a second stage} calculates {TAIL ~ one fourth and three fourths amplitude values}, and a third stage calculates one eighth, three eighths, five eighths, and seven eighths amplitude values 
calculates
A first stage of the interpolation circuit calculates a one half amplitude value ; { HEAD ~ a second stage } calculates { TAIL ~ one fourth and three fourths amplitude values } , and a third stage calculates one eighth , three eighths , five eighths , and seven eighths amplitude values
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH