EIS Spectrum Analyser
Menu: Logarithmic Kramers-Kronig Test
Analysis / Log-KK Check.
Generates a plot of residuals between modulus of impedance of
calculated spectra based on Log-KK approach and modulus of impedance of
Logarithmic Kramers-Kronig 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 Kramers-Kronig test is based on interrelation between the logarithm of the impedance modulus Z and the phase angle shift φ
for two-pole 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
Normally, the lower the peak-to-peak 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 near-to-perfect data due to limitations of Log-KK
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 Kramers-Kronig test
Note 2: Large peak-to-peak amplitude of the residuals may be caused by noisy data.
EIS Spectrum Analyser, 2008