> Bad idea. =A0Count every pulse, and you get 4x more resolution or update =
rate,
> or some combination of the two.
>
> Keep in mind that signals in cars can be noisy. =A0Even if the 0 and 1 le=
vels
> are fine, the noise will cause jitter on the edges. =A0Pulses within a si=
ngle
> revolution may not all be symmetric or spaced exactly evenly. =A0Always d=
o a
> little low pass filtering on the period in these cases. =A0Fortunately th=
is is
> easy to do with a reasonable time constant since you get a new measuremen=
t
> every pulse, and usually you don't need to update the speed anywhere near
> that fast.

Very much in agreement.
You can also "sanity-check" your data, knowing that the engine can't
instantly change its speed by a large amount.  If the input has
changed more than is reasonable, you can make a decision on whether or
not to ignore it.

--=20
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