Compensation of the frequency dependent systematic error of a time-division watt converter using two multipliers

The paper presents an original method for the compensation of the frequency-dependent systematic error of time-division multipliers (TDMs). The method is based on using two identical multipliers working at different conversion frequencies. Full compensation of the error can be achieved using simple calculations, taking into account only the values of the output signals of the multipliers and the ratio of the conversion frequencies. It has been shown theoretically by computer simulation that the errors in the method are less than +50 μW/W for input signal frequencies up to one tenth of the lower conversion frequency. For practical realizations of the method, there is no need to use two complete TDMs because some simplifications are possible. A prototype watt converter based on this method has been developed, and results of measurements show that an uncertainty of ±50 μW/W is achieved in the input signal frequency range from 50 Hz to 10 kHz at a lower conversion frequency of only 100 kHz