Abstract: In an analog test system for testing integrated circuit chips, AC level calibration is achieved by adding a minimal number of new elements and more fully utilizing elements existing in the system. A reference voltage from an existing precision DC power source is fed to an analog switching device. A control signal is also fed into the analog switching device from an existing digital signal generator. Based on the control signal, the analog switching device converts the reference voltage into a rectangular waveform signal, which is then digitized. The digital signal is analyzed, and data from the digital signal is compared with reference data, and the AC level error, if any, is determined. AC level calibration is based on this error.