On 25/06/2018 15:05, NY wrote:

It *has* to integrate over a fairly long time and number of rotations to
avoid it being triggered every time the car turns a corner and the outer
wheel rotates faster than the inner wheel.

Or, given that it knows the steering wheel angle, it might chose to
ignore readings during turns.

I would imagine (and I've not
done the calculations) that the difference in rotational speed between
inner and outer wheel on a bend will be significantly more than the
difference in rotational speed between a correctly-inflated and an
under-inflated wheel

I'd say much greater

so any TPMS has to average out this large
difference in order to be able to detect a much smaller one.