Any engineers on board? Zero on the shot clock, no horn

[pizanno]

This has been bothering me for a week.

Had a dead ball situation with zero on the shot clock with no horn in a game last week. No biggie. We played on.
(NCAA 2-11-9) When the shot clock indicates zeros but the shot-clock horn has not sounded, the shot-clock time has not expired.

Until then, I didn't believe it was possible, as I always observed shot clocks delaying a bit before the display changing from 35 to 34 (or 30 to 29 for women) implying the display won't change until the internal timer gets to 34.0 or 29.0. I've since tested shot clocks myself to confirm there is, in fact, a "delay", in case we have an end of game situation where clock differential comes into play.

My question:

Any engineers here who can explain the mechanics of the shot clock? Not just theoretical, but someone with experience with the architecture of shot clocks.

My brain has me believing there's actually an extra 0.9 seconds coming into play on the clock.

Consider:

* Not an operator error or reaction time question.
* I realize the rule book doesn't cover (and thus, not allow) discussing tenths of seconds for shot clock. This is what's racking my brain.

Someone please help so I can get some sleep!