Switching power meter for frequencies up to 1 MHz

This paper describes a power measurement setup able to measure power up to the MHz region. The setup consists of a commercial digitizer together with a switch unit and buffer amplifiers to alternately measure the voltage and current channel. This significantly reduces the need for flat frequency response of the setup. The method described in this paper makes complex ratio measurements possible in the range of 50 Hz up to 1 MHz with an uncertainty of a few parts in 10⁶.