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