How to get the time that a signal stays between certain values?

I have acquired diesel engine rpm measurement data from CAN bus. I have the rpm values with a timestamp with about 50Hz frequency. Now I need to be able to define the time the engine rpm stays between certain upper and lower boundaries (in other words, how long the rpm stays on a certain rpm band). How to do that?

Answer 1

[Walter Roberson]

logicalvec = rpm >= lowerbound & rpm <= upperbound;
times_in_range = timestamps(logicalvec);

If you need to look for transition times, you can search

[false, logicalvec, false]

using strfind, looking for [0 1] to find the times it turns on, and looking for [1 0] for the times it turns off. Although strfind is for "strings", it turns out to work for these cases too.