Spectrum analysis can be used to create {TAIL ~ a profile} of an active signal source that can be analyzed to identify the type of source producing {HEAD ~ the signal} 
Spectrum analysis can be used to create { TAIL ~ a profile } of an active signal source that can be analyzed to identify the type of source producing { HEAD ~ the signal }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD