In {TAIL ~ the present invention}, {HEAD ~ the signal} to be measured is not first converted to DC 
In { TAIL ~ the present invention } , { HEAD ~ the signal } to be measured is not first converted to DC
REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH