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Asked by Lisa Justin on 21 Aug 2012

i need the sampling frequenccy of a give time series data. it is a 1x31225 time data if i choose any two point say x(:,1) and x(:,2)

1/x(:,2)-x(:,1) does not give a likely sampling frequency, it gives about 0.2144 for instance. please help out

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Answer by Star Strider on 21 Aug 2012

Edited by Star Strider on 21 Aug 2012

Accepted answer

All may not be lost. When I searched for information on `.sif` files, I came up with a number of different definitions, including Andor Scan Information File (there are at least two TMW File Exchange entries for those), and Cytoscape Simple Interaction Format. (They are also Windows Setup Information Files, but those likely aren't the ones you are interested in.)

What generated your `.sif` file, and what does it contain? How many rows and columns should it have? If it is supposed to be a matrix rather than a vector, it may be possible to get the time data (if there is a time vector in the matrix) by doing `reshape` on it.

Answer by Azzi Abdelmalek on 21 Aug 2012

if x(:,1) is time and x(:,2) is your signal

then, if the sample frequency is constante

f=1/((x(2,1)-x(1,1))

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Lisa Justin on 21 Aug 2012

i guess it was lost from conversion from a SIF file. but i have only the converted file, any ideas

Azzi Abdelmalek on 19 Oct 2012

Without a vector time, we can't find your sample frequency. I can't guess what happens to your file.

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