1-st i attempted to make sense of
this beast (src.) . . . is the T3 right polarity? coz i couldn't get this thing to generate any useful output that way ... anyway there's what it end up :
and it's damn slow for dif. input stage -- where the good point is it's having a high impedance input
2-nd we got something called CURRENT-MODE SCHMITT TRIGGER
if it's an OE output -- then here some more realistic boundary for it :
it appears fast and even faster - but input seems to be very low impedance???
next i should try some j-Fet 1-s ...