Voltech AT5600, Руководство пользователя

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C H A P T E R 7 – T E S T S A N D T E S T C O N D I T I O N S
AT5600 User Manual 98-119 issue 14
Page 95
7.3. Explanation of Integration
Integration is used during the Test Execution measurement process. The AT5600
allows a choice of three types of measurement Integration, Short, Medium, and
Long. The Integration type is selected when the Test Program is created using
the Editor Software.
Each measurement result from the AT5600 is derived by making a sequence of
consecutive sub-measurements and computing the mean of these sub-
measurements. For example, a resistance test of the 10 sub-measurements
below would report a mean value of 10.0 ohms: -
10.20 9.90 9.90 9.93 9.80 9.85 10.10 9.98 10.10 9.91
The key decision that the AT5600 must make is how many sub-measurements to
take to produce a result. This is done by using the mathematics of statistical
analysis.
The variation in the values of sub-measurements follows what is termed a "normal
distribution" in statistical analysis:
A plot of a normal distribution (or bell-shaped curve)
where each band has a width of 1 standard deviation.
As each sample is collected the AT5600 computes the standard error of the
mean (https://en.wikipedia.org/wiki/Standard_error):
Where:
s is the sample standard deviation (i.e., the sample-based estimate of the
standard deviation of the population), and
n is the size (number of observations) of the sample.
This value is used to compute the relative standard error which is the
standard error divided by the mean and expressed as a percentage.
https://en.wikipedia.org/wiki/Standard_error#Relative_standard_error
The larger the number of sub-measurements (n) the smaller will be the relative
standard error, but the greater the time to get a result. The AT5600 provides for