{HEAD ~ Substantially accurate calibration} of {TAIL ~ output impedance} of a device under test to within a predetermined range of allowable impedance 
{ HEAD ~ Substantially accurate calibration } of { TAIL ~ output impedance } of a device under test to within a predetermined range of allowable impedance
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH