A visual evoked response simulator

A Visual Evoked Response (VER) phantom, simulating a normal waveform response, has been designed to assist with calibration and quality assurance of ophthalmic electrophysiological instrumentation. This VER SIMulator (VERSIM) is based on a simple microprocessor design with a digitised waveform stored as an array in memory and converted to an analog signal when output. Frequency is controlled by a software delay between each byte of data output and a voltage divider network defines the range of voltages. To simulate a subject isolated from the electrical mains supply the VERSIM is battery powered.