A decoder output signal is provided, however, only if {HEAD ~ a second output signal} from the comparator is provided within a predetermined period of time following the provision of {TAIL ~ the first output signal} therefrom 
A decoder output signal is provided , however , only if { HEAD ~ a second output signal } from the comparator is provided within a predetermined period of time following the provision of { TAIL ~ the first output signal } therefrom
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH