This paper describes the design of a three-phase calibrator, i.e. generator of voltage and current signals. The core of the calibrator is an IGBT converter with a low-pass LRC filter at the output, which eliminates higher voltage and current harmonics. The modulation technique used to control the IGBT conduction process is sinusoidal pulse width modulation (SPWM). Amplitudes and phase angles are regulated to compensate for system nonlinearity, temperature changes, voltage drops on parasitic components, etc. The implemented algorithms serve to generate the SPWM signal that will be controlled by the IGBT bridge. The processor with FPGA technology (Programmable Logic Gate Arrays) enables very high speeds of digital signal processing. The speeds that the FPGA processor itself achieves in parallelism are in the nanosecond range. The experimental results show the great potential of the proposed method for the design of calibrators for various electrical measuring instruments.