Abstract: A power measurement and calibration system provides power and line frequency measurements by using a bandpass filter having complex voltage and current outputs from which real and imaginary power components can be determined. Calibration of the filter may be omitted if a complex wavelet filter is used to implement the bandpass filter and a determination of line frequency can also be provided for downstream use. A processor receiving data from the output of the filter can compute real and imaginary power, power factor and the line frequency. The filter may be implemented by a processor executing program instructions, or a digital circuit implementing the filter and optionally a CORDIC rotator for computing the current-to-voltage phase relationship can provide input to the processor for power measurement and calibration of the sample rate to line frequency relationship and for other uses.