{HEAD ~ The squared signal} is integrated over a period related to the frequency fm to provide {TAIL ~ a dc signal} 
{ HEAD ~ The squared signal } is integrated over a period related to the frequency fm to provide { TAIL ~ a dc signal }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL