Therefore this circuit produces {HEAD ~ a digital ramp signal} with a slope and frequency proportional to {TAIL ~ the numerical value} of the input digital word 
Therefore this circuit produces { HEAD ~ a digital ramp signal } with a slope and frequency proportional to { TAIL ~ the numerical value } of the input digital word
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH