{TAIL ~ The system} 4 in which the means for providing {HEAD ~ a test signal} is a video signal storage and retrieval system 
{ TAIL ~ The system } 4 in which the means for providing { HEAD ~ a test signal } is a video signal storage and retrieval system
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH