A comparator receives {TAIL ~ a threshold value} and compares {HEAD ~ each} of the intermediate amplitude values to the threshold value 
A comparator receives { TAIL ~ a threshold value } and compares { HEAD ~ each } of the intermediate amplitude values to the threshold value
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH