First, {HEAD ~ the video signals} pass through the video operational amplifier and {TAIL ~ video buffer} 312 and the video switch circuit 306 
pass through
First , { HEAD ~ the video signals } pass through the video operational amplifier and { TAIL ~ video buffer } 312 and the video switch circuit 306
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH