Depending on the nature of the signals of interest, the signals detected may be reflected signals generated in {HEAD ~ response} to {TAIL ~ a carrier signal} produced by the communication device, or active signals produced by active sources 
Depending on the nature of the signals of interest , the signals detected may be reflected signals generated in { HEAD ~ response } to { TAIL ~ a carrier signal } produced by the communication device , or active signals produced by active sources
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH