A method and an apparatus provides for calibrating a test system for an integrated semiconductor circuit, a pattern generator of the test system generating a test signal in the form of a pattern of successive rising and falling edges, which is composed of superposed sub-patterns formed via different internal paths of the pattern generator. The pattern generator provides an information signal for a measuring device of the test system, which identifies the edges of at least one sub-pattern of the test signal with regard to their origin from one of the internal paths. The calibration is carried out for the internal path separately using the information signal.
