StddevInTime('Expression','Interval',' Reset=0')

Arguments

'Expression'

Measured value, for which the standard deviation is formed

'Interval'

Specification of the length of the interval in seconds, over which the standard deviation should be calculated.

'Reset'

Optional parameter (default = 0) to stop and restart the calculation

'Reset' = 0

Perform calculation

'Reset' = 1

Stop calculation and set result to 0

'Reset' = 2

Stop calculation and keep result

'Reset' = 3

Calculate now and then stop calculation
Description

This function returns the standard deviation of 'Expression' over each time interval of the length 'Interval' as its result. The calculation can be stopped using the optional parameter, 'Reset.'

The standard deviation is calculated by the following formula:
Example

For a signal waveform, the standard deviation should be determined in time intervals of one second. A reset is not necessary.
Solution

In the figure below the blue curve shows the measured values and the red curve shows the standard deviation in the intervals of length of one second.