This overview describes data-treatment for Electrochemical Noise measurements in the ZRA-control mode. Data-treatment for ECN measurements in potentiostatic or galvanostatic modes do not require a separate discussion. Those modes are simpler than ZRA mode in that only current or potential noise, not both, is measured and analyzed, but they are otherwise similar.
The noise calculation is straightforward. Each block of current-and-potential-versus-time data is described by three arrays:
A DC trend is calculated from the data arrays using a standard linear best fit:
The noise of the block is estimated by subtracting the DC trend and calculating the RMS of the residual AC signal:
These values are a measure of current noise and potential noise at the time the block was acquired. These values, along with the time at the start of the block, are appended to the output curve. The output curve is therefore current noise and potential noise versus time.