The H countdown circuit 14 counts clocks of the internal clock, and generates an H reset signal which is {HEAD ~ a pulse} indicating {TAIL ~ one horizontal period} 
indicating
The H countdown circuit 14 counts clocks of the internal clock , and generates an H reset signal which is { HEAD ~ a pulse } indicating { TAIL ~ one horizontal period }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL