History of InputTrigger/RunOut
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2018-02-12 06:25:33 . . . . catv-86-101-250-44.catv.broadband.hu [noise suppression adaptive hysteresis vs. naiv signal detection]
2018-02-12 06:23:04 . . . . catv-86-101-250-44.catv.broadband.hu [noise suppression adaptive hysteresis vs. naiv signal detection]
2018-02-12 06:13:25 . . . . catv-86-101-250-44.catv.broadband.hu [generated severe runout png, and wav]
2018-02-12 05:02:54 . . . . catv-86-101-250-44.catv.broadband.hu [lower R37 for serious wheel runout]
2006-03-15 21:43:08 . . . . MembersPage/MarcellGal [new waveform]
2006-03-15 21:43:08 . . . . MembersPage/MarcellGal [fixed missing tooth shape]
2006-03-15 21:43:08 . . . . 1-1-1-39a.gam.gbg.bostream.se [Explained the amplitude diff over rpm.]
2006-03-15 21:43:08 . . . . MembersPage/MarcellGal [perfect example; cleanup; note on polarity]
See complete list (16 entries)


Changes by last author:

Changed:
triggerwheel is not centered on the shaft
Triggerwheel NOT perfectly centered on the shaft
Changed:
If in doubt, record VR signal with scope or your notebook soundcard.
If in doubt, record VR signal with scope or your notebook soundcard.

m582_400-9999_120_99_1000_800.runout.png

Unzip and play: [generated soundfile with severe runout illness] (also another abnormality: slightly greater missing tooth amplitude).

Added:
* in case of "serious wheel runout" (systematic amplitude variations within 1 rotation), eg. at 2300 RPM R37=100k..270k (or 150..360k in parallel with the 1M) instead of the 1M resistor can help the LM1815pin7 "forget the amplitude" faster. (so the primtrig VR R37*C38 gets shorter, C38=220nF)

Noise suppression: Adaptive hysteresis is designed to suppress eg. 1000mV noise at 1500mV signal amplitude, but still allow sensing a 240mV signal during cranking (yes, smaller than the suppressed noise at higher RPM).

* Easy to see that the otherwise awesome adaptive hysteresis does not work well with severe runout problem

* this is one case where a naiv trigger detection without noise suppression works better (although more sensitive to noise from other sources)

** or the adaptive hysteresis needs to be (at least partially) suppressed, eg. with lower R37 (and/or higher R181) resistance

Changed:
** Is the sensor mounting bracket firm ?
** Is the sensor mounting bracket so firm that we could lift the engine with it ?