Please watch the video from ~ 0:45 to fully understand what i mean . Wad this a rough guess from the tv broadcast or was this actual telemetry data back then ?
In 2000, the FIA race control was receiving onboard telemetry from cars in real time through a system that combined radio waves and IR signals, allowing for continuous data transmission during a race. This data which included speed, engine data, and other metrix, was then processed and displayed on screens in race control for analysis. Broadcast teams would also tap into this data, often with some delay, to show it on TV for viewers.
Looking at the extreme responsiveness of the analog display (eg during downshifting), we are looking at either: a) good quality telemetry or b)very clever frequency analysis from the audio.
So yes ... thats the question ! Did tv broadcasters get the revs from an audio frequency analysis or were they provided with live telemetry data from FIA ?
The rev data is interesting when you watch different teams in 2001 with the knowledge of engine details today
I'm guessing they used telemetry, DSP would introduce too much lag. Say 100 rpm resolution, then 2 Hz, so 0.5 seconds lag.1000 rpm res would be 50 ms lag which is probably fast enough.