{HEAD ~ The spectrum} is measured over a time period of 1 to 1000 seconds, at {TAIL ~ intervals} of 5 to 10 milliseconds or less 
{ HEAD ~ The spectrum } is measured over a time period of 1 to 1000 seconds , at { TAIL ~ intervals } of 5 to 10 milliseconds or less
HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH