There is a new video in F1TV about how timing works:
https://f1tv.formula1.com/detail/100000 ... tech-works
OK but not great, IMO.
It doesn't directly address your question, but they mention a "quality indicator" on "timing loop passes", perhaps those are the low quality signals that require some extra processing or even checking to produce the official time? Say, if a car passes over he loop while bouncing on the kerb or any other physical disturbance.
It is surprising how manual they describe the system as being, loops, transponders and all that, but also a guy with paper and pen noting the car numbers as they pass the finish line and a 2-lap response time to check, analyze, then write a report on a "possible" jump start which then needs to be manually re-analyzed.
Another interesting tidbit: they are working on bringing timing to the 1/10000th of a second. 0.00001 seconds, at 300 km/h, is 8.3 cm. Better cut those loop grooves straight!
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