In accordance with another feature of the invention, a Schmitt trigger can be used to generate {HEAD ~ pulses} from {TAIL ~ the alternating current control voltage} 
from
In accordance with another feature of the invention , a Schmitt trigger can be used to generate { HEAD ~ pulses } from { TAIL ~ the alternating current control voltage }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL