Locate Starting Point of Signal in Time Series

made by halleyhit in about 2013 and published in 2018
Email: halleyhit@sjtu.edu.cn or halley-at-hit@163.com

When receiving time series in experiments, we often find some zeros before wanted signal. Also, it is difficult to locate the starting point with noise pollution. e.g. when locating partial discharge by ultra high frequency sensor, the first step is to locate starting time of each PD pulse.

This function uses ENERGY CRITERION algorithm, which can be found in "Sacha M. Markalous, Stefan Tenbohlen and Kurt Feser, Detection and Location of Partial Discharges in Power Transformers using Acoustic and Electromagnetic Signals. IEEE Transactions on Dielectrics and Electrical Insulation Vol. 15, No. 6; December 2008"

HOW to use
StartingPoint=userstart(TimeSeries)
TimeSeries is a double vector
StartingPoint is the order number of starting point

EXAMPLE
a=[zeros(1,20) ones(1,20)]+rand(1,40);% Step signal with noise
S=userstart(a) % Starting point