Radar electronic support measures (ESM) systems perform the functions of threat detection and area surveillance to determine the identity and bearing of surrounding radar emitters . These ESM receivers have a wide frequency band and their antennas have a wide coverage pattern. These features of the ESM reeQiver are necessary to increase the instantaneous coverage and to enhance the probability of in:terception. However , the ESM receiver is vulnerable to overlapping pulses, these pulses which tyrrive simultaneously or partially are time overlapped to the ESM receiver input In this work a quelling model is performed to describe the arrival process of radar pulses at the input of an TESM receiver. From this arrival model, the probability of pulse overlapping is determined. for an arbitrary arrival rate . The effect of this undesired pulse overlapping on the measurements performed by an ESM receiver and consequently the output digital words that describe the arrival pulse train is evaluated in two cases. The first case which is denoted as paraPyzable receiver type , where the ESM receiver can only process a pulse which arrives after a fix(ed time from the last pulse processed. The second case is denoted as non paralyzable receiver, where the receiver is ready to process a new :wise, as soot as the life time of the previous pulse is expired . A computer program is constructed to simulate the operation of an ESM receiver in these two cases . The results show that the ratio of successfully processed pulses in case of non paralyzable processing is larger than the case of a paralyzable processing .