{HEAD ~ This jitter device} allows {TAIL ~ any test or sample signal} to be used for testing such equipment 
allows
{ HEAD ~ This jitter device } allows { TAIL ~ any test or sample signal } to be used for testing such equipment
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH