For Distorted Waveshapes of All Types
The success of the Valhalla 2100 series wattmeter design is centered around a four-quadrant multiplier.
The significance of the four quadrant theory is to provide a proper computation for watts under any phase relation between voltage and current to ensure that indeed EI cos θ or true power consumption is being measured. That is, the four quadrant multiplier takes the instantaneous product of both E and I (instantaneous watts). Continuous integration of instantaneous watts provides a true power measurement regardless of waveshapes within the bandwidth limits of the converter.
Valhalla uses a proprietary wideband VLSI multiplier design to capture high order harmonics and thereby ensure an accurate watts product. Once the multiplicative watts product is achieved, it is in turn filtered, passed through the A to D (Analog to Digital converter) and displayed.