# How to detect trigger point of signal rising

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Kanakaiah Jakkula on 19 Jan 2018
Answered: Fatih Erden on 28 Aug 2018
Hi,
I have below time series data(one data per seconds), each column is one variable. I want to know which variable triggers to rise or fall the signal in last column(Meaning: after which variable's signal rise or fall will triggers the last column signal start changing from zeor to 0.1).
0 0 0 0 0 12 0
0 0 0 3 3 12 0
0 0 0 3 3 12 0
0 0 0 3 3 12 0
0 0 0 3 3 12 0
0 0 0 3 3 12 0
0 0 3 3 3 12 0
0.3 0 3 3 3 12 0.1
0.3 0 3 3 3 12 0.1
0.3 1 3 3 3 12 0.1
0.3 1 3 3 3 12 0
0.3 1 3 3 3 12 0.2
0.3 1 3 3 3 12 0.2
0.3 1 3 3 3 12 0.2

Bernhard Suhm on 23 Jan 2018
You could apply the CUSUM algorithm. You can find an example with code at https://dsp.stackexchange.com/questions/30039/detect-to-rising-stable-and-falling-point-in-non-smooth-rectangular-wave
Kanakaiah Jakkula on 24 Jan 2018
Sir,
I know the point (in last column) where it is changed its direction for first time, and so on. But I want to detect after which column(column1~6) data fall or raise or settled, then column7 (last column) data chage its direction(rise or fall)for first time.

Fatih Erden on 28 Aug 2018
This may be thought of as a change point detection problem. Depending on the type of your signal, you can use many techniques including Bayesian change point detection, fractal dimension or variance analysis. There is also a new function called findchangepts(x). Using this function you can find the change points (specified by the user) where the mean/rms/std values change the most (at https://www.mathworks.com/help/signal/ref/findchangepts.html).