AC (RMS) / DC (Mean) / Frequency values

The Channel Checker shows 4 values for each channel input:

AC+DC (RMS)
- Geometric sum of the AC and DC values. May not match the numerical sum of the AC and DC values.
AC (RMS)
- AC-only RMS value of the signal input.
DC (Mean)
- DC-only value of the signal input.
Frequency
- The frequency count of the signal. Firmware v4.0.5 and above calculates this based on the zero-crossing of the signal, firmware prior to v4.0.5 calculates frequency based around the mean-value of the signal.