摘要:We consider a compound Poisson process with symmetric Bernoulli jumps, observed at times iΔ for i=0,1,… over [0,T], for different sizes of Δ=ΔT relative to T in the limit T→∞. We quantify the smooth statistical transition from a microscopic Poissonian regime (when ΔT→0) to a macroscopic Gaussian regime (when ΔT→∞). The classical quadratic variation estimator is efficient for estimating the intensity of the Poisson process in both microscopic and macroscopic scales but surprisingly, it shows a substantial loss of information in the intermediate scale ΔT→Δ∞∈(0,∞). This loss can be explicitly related to Δ∞. We provide an estimator that is efficient simultaneously in microscopic, intermediate and macroscopic regimes. We discuss the implications of these findings beyond this idealised framework.