Transient detection in the presence of noise is a problem which occurs in many areas of engineering. A desription is given of a classifier system suitable for the identification of high frequency waveforms. It uses the Wavelet Transform for signal pre-processing and a forward feature selection algorithm. A Radial Basis Function neural network is employed to model the class conditional probability density function. A short review of statistical pattern recognition is presented. The classifier is applied to the identification of a number of difficult to classify, high frequency Acoustic Emission signals.