ANTWORTBESTIMMUNG

A method and apparatus for assessing the characteristic response of a medium to an excitation transient of predetermined duration which causes the medium to emit a series of signals over a period of time which is long relative to the duration of the excitation transient. The signals are detected and the duration of each interval between successive signals is measured. A relationship relating the interval between the excitation transient and the emission of each signal to the interval between each signal and the preceding signal in the series is derived to represent the characteristic response. The interval between the excitation transient and the emission of each signal may be plotted against the interval between each signal and the preceding signal in the series and a curve may be fitted to that plot. The position of a minimum value of the interval between the excitation transient and the emission of each signal as represented by the curve is then determined, and the interval between successive signals corresponding to the position of the minimum is then determined to provide a measure of the characteristic response of the medium. The excitation transient may be a pulse.