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