A circuit arrangement that utilizes digital data representative of the amplitude of an RF pulse envelope is disclosed. The circuit arrangement comprises a PROM having prestored and addressable routines and a nine-stage sequentially arranged eight (8) bit latches that are clocked at a rage of 25 nanoseconds, when the maximum value of the RF pulse envelope is within a selectable 6dB or 3 dB point and generates a control signal SV that causes the data in the upper stages of the nine-stage latches to be frozen and further generates an address that is routed to the PROM, wherein a family of waveform shapes are accessed. The circuit arrangement provides for four(4) data points that are examined by prestored routines of the PROM and compared against the prestored family of waveform shapes, and, upon a match therebetween, determines the time of arrival (TOA) and pulse width of the RF pulse envelope being received by the circuit arrangement.