The oscillating circuit 423 is used for creating oscillating signal and {HEAD ~ the variable resistor} 426 controls {TAIL ~ the oscillating frequency} 
The oscillating circuit 423 is used for creating oscillating signal and { HEAD ~ the variable resistor } 426 controls { TAIL ~ the oscillating frequency }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL