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