Abstract: The invention relates to a perturbation signal recorder. An input circuit receives a series of signals to be monitored and samples them in order to supply in respect of each sample a digital word to a pre-memory circuit which preserves the n most recent digital words. In the presence of a perturbation, a central unit excites a main memory circuit in order that it records the n most recent digital words at the time of the perturbation, as well as the following digital words during and after the perturbation. The contents of the main memory are thus transferred at a slow rate to an output circuit, which re-transforms the signals to an analogue form and applies them to a graphic recorder.