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Menu: Logarithmic KramersKronig Test
Analysis / LogKK Check.
Generates a plot of residuals between modulus of impedance of
calculated spectra based on LogKK approach and modulus of impedance of
experimental spectra.
Logarithmic KramersKronig test procedure implemented in EIS Spectrum Analyser is based on approximations presented in [C.A.Schiller et al. Phys. Chem. Chem. Phys., 3 (2001) 374].
Logarithmic KramersKronig test is based on interrelation between the logarithm of the impedance modulus Z and the phase angle shift φ
for twopole transfer functions. The validation of data can be
performed through inspection of the relative residual plot between
measured impedance modulus dependence on angular frequency and another
one calculated from experimental dependence of phase shift on the
frequency:
Normally, the lower the peaktopeak amplitude in the residuals plots the better is quality of experimental impedance data.
Note 1: depending on properties of the dependence of the
phase shift on frequency, the procedure sometimes can give large
residuals even for neartoperfect data due to limitations of LogKK
approach itself and a straight numerical integration/differentiation
realized in this routine. Practically, residuals less than 2% may
indicate ‘good’ quality of data. For more comprehensive validation of a
spectrum, use this test in a combination with Linear KramersKronig test
Note 2: Large peaktopeak amplitude of the residuals may be caused by noisy data.
EIS Spectrum Analyser, 2008

