Meaning
Error in time-domain alignment between the applied excitation signal and the measured response of an electrochemical cell. A significant phase angle distortion results in the incorrect calculation of the real and imaginary components of impedance. This phenomenon is usually caused by propagation delays in the measurement electronics or by uncompensated capacitance in the cables.
It sets the upper frequency limit for accurate electrochemical impedance spectroscopy.
Filter Lag
Analog filters used to remove noise from the measurement signal can introduce a phase shift. If the system does not compensate for this lag, phase angle distortion will appear as a false capacitive or inductive effect. High-speed digital signal processors are used to minimize this delay by performing filtering in the digital domain.
Calibration with a purely resistive standard helps to identify the native phase shift of the equipment.
Sampling Sync
Simultaneous measurement of current and voltage is required to calculate the phase correctly. Any timing offset between the two sampling channels leads to phase angle distortion. At a frequency of ten kilohertz, a timing error of just one microsecond can result in a phase error of several degrees.
Laboratory hardware must use a common clock for all analog-to-digital converters to prevent this drift. This synchronization ensures that the calculated power loss accurately reflects the heat generated inside the cell.
Cable Length
Signal travel time becomes a factor when test leads are long. This contributes to phase angle distortion in high-frequency tests because the signal at the probe tip is slightly behind the signal at the source. Shorter leads or active compensation techniques are employed to maintain accuracy.
The resulting data is only valid if the phase error remains below a small fraction of a degree across the entire frequency range.
