A system for analyzing an analogue signal comprising randomly spaced events, the event having an event height, comprises: Converting the signal to a series of samples S(t), with t the moment of sampling, thereby forming a sampled, discrete time signal, Detecting the presence of an event, the event detected at t=T, Estimating the event height Using a model (412, FIG. 5) to estimate a noise contribution N(t) for t=(T−Δ1) to t=(T+Δ2), the noise contribution derived from samples S(t) with t≤(T−Δ1) and/or samples S(t) with t≥(T+Δ2), with Δ1 and Δ2 predetermined or preset time periods having a value such that the event has a negligible contribution to samples taken before (T−Δ1) or after (T+Δ2), Estimating the event height E by integrating the series of samples from (T−Δ1) to (T+Δ2) minus the noise contribution for said samples, E=Σt=(T−Δ1)t=(T+Δ2)S(t)−Σt=(T−Δ1)t=(T+Δ2)N(t)=Σt=(T−Δ1)t=(T+Δ2)[S(t)−N(t)].