To provide a mask circuit in {HEAD ~ a control device} which controls {TAIL ~ each signal}, enables the timing system to exactly perceive a swimmers touch 
controls
To provide a mask circuit in { HEAD ~ a control device } which controls { TAIL ~ each signal } , enables the timing system to exactly perceive a swimmers touch
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH