Hioki IM7580, Инструкция по эксплуатации

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Equivalent Circuit Analysis Function
Differences between observed values and simulated values
The difference between observed values and simulated values is calculated for each measurement
parameter in order to judge the suitability of equivalent circuit analysis results. The range for
calculating this difference is the frequency range that is analyzed or the frequency range for the
segment No. that is analyzed. The difference is calculated using the following procedure:
(1) The squares of the difference between each observed and simulated value pair for the
frequency sweep count are added together.
(2) The result is divided by the frequency sweep count to obtain the mean residual sum of
squares.
(3) The square root is calculated.
This can be specifically expressed with the following formula (A).
Σ
(observed value - simulated value)
2
/ n
n: sweep count
A =
However, when using this method with circuits whose impedance frequency characteristics exhibit
local extreme values (local maximum or local minimum values), difference values for frequency ranges
that do not contain local extreme values will be less than difference values for frequency ranges near
local extreme values, as shown in the figure below. Consequently, the area enclosed with the dotted
line in the figure is excluded when calculating the difference between observed and simulated values.
The following calculation procedure is used for the area enclosed with the dotted line.
(1) The difference value calculated by adding quantity A to the observed value for the measurement
frequency that generated the local extreme value is used as the upper limit value, and the
difference calculated by subtracting the quantity A from the observed value for the measurement
frequency that generated the local extreme value is used as the lower limit value.
(2) If the simulated value for the measurement frequency that generated the local extreme value
falls outside the range defined by the upper and lower limit values calculated in (1) above, the
upper and lower limit values for the observed values before and after the local extreme value
are calculated as in (1) above and repeatedly compared to the simulated values.
(3) If the simulated value falls inside the range defined by the upper and lower limit values for
the measurement frequencies before and after the local extreme value, the area is used to
calculate the difference, and the areas used in (1) and (2) above become the area shown with
the dotted line.
Z
Frequency
: Observed value
: Simulated value