Reference pulse, how to extract it?

I guess I've done a Bayesian architecture for a car... I drove a '68 T-Bird up 101 (BAY area :-) with a scope in the passenger seat, my boss in the back... me sitting cross-legged in the driver's seat, controlling speed and brakes with buttons on the steering wheel... at over 100MPH....

My boss refused to ever ride with me again ;-)

...Jim Thompson

"Jacques St-Pierre" skrev i en meddelelse news:TJ0Oj.129$XI1.109@edtnps91...

You could lock a PLL to the teeth and clock a state machine (modula 4 counter) with it and XOR the output from the state machine at State 0, where the normal teeth are, with the sensor signal. That way the reference slot should show up as a 1 every cycle.

Phase lock to a 300:1 speed variation? Bwahahahahahahaha ;-)

...Jim Thompson

You can do that. I built a lock-in once that used a VCO with an exponential frequency vs voltage curve, plus loop filters based on operational transconductance amps whose bias current came from a F-V converter. All the poles tracked the operating frequency, so the loop dynamics were very nearly constant over a 1000:1 frequency range.

You wouldn't do it that way nowadays, but it was fun at the time.

Cheers,

Phil Hobbs

If you compose them in a fixed-width font (either set your newsclient for "courier", or compose it in, say, Notepad and copy/paste it.

As far as sensing them, I"d be tempted to do a timer capture and simply count intervals - when you get 2x 1/2 time in a row, that's your syne pulse.

Or any one of a billion other ways. ;-)

Good Luck! Rich