1. An electronic article surveillance system, comprising: means for generating and radiating an interrogation signal in an interrogation zone; antenna means for receiving an analog signal present in the interrogation zone; first means for processing the signal received by the antenna means to form a plurality of input parameter signals; and second means for performing a neural network processing algorithm with respect to said plurality of input parameter signals for simultaneous detection and discrimination of plural characteristics of the received signal to determine whether an electronic surveillance marker of a predetermined type having predetermined signal characteristics is present in the interrogation zone.