Until now, {HEAD ~ the transmission power} has been controlled exclusively by varying the gain of {TAIL ~ the power amplifier} 
Until now , { HEAD ~ the transmission power } has been controlled exclusively by varying the gain of { TAIL ~ the power amplifier }
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL