AC power calibration system with phase feedback

A ´phantom´ power calibration system that combines a digital phase angle generator with a 120-V/75-mA voltage amplifier and a voltage-controlled, almost ideal, 5-A/5-V current source is described. Voltages up to 120 V at burdens of 75 mA and currents of up to 6 A at compliance voltages of 5 V are available up to 6 kHz. The current amplifier incorporates a nearly ideal current source output, a broadband shunt, and a set of nearly ideal, wideband, low-distortion, 10*, differential amplifiers with common mode rejection ratios exceeding 96 dB at 5 kHz. The system provides phase-controllable voltages and currents from 20 Hz to 5 kHz with phase accuracies approaching 0.001/sup 0/.<>