PROCESSING OF RECORDED DATA

摘要

A coil (6) forming part of a tuned circuit (8) is wound around a gapped magnetic core (2). As a magnetic stripe (14) is passed under core (2), variations to the amplitude and frequency of the circuit (8) occur dependent upon the magnetic data on the strip (14). Selected data are manipulated to derive several values for combination via AND-gate (46). Only if the combination value is above a threshold value is an indication given that the stripe (14) is genuine and not an attempted copy.