I've not used it, but doc (and error message) indicate that the time pulse input is either a fixed scalar or increasing time for the pulses--
tp — Pulse times
scalar | vector
Pulse times, specified as a scalar or a vector.
- Scalar — a constant time interval over which rotations occur.
- Vector — nonnegative, strictly increasing instants that define constant rotational phase.
It appears maybe from your description and the error you have an actual tachometer input signal, not the pulse times; for starters try the hint above with
tsa(data(:,1), fs, tachorpm(tach));
as a guess without seeinng the data or knowing for sure what your variable tach is -- I'm presuming it is data(:,3) from the description.
