Electronic security system having improved noise discrimination

摘要: An electronic security system adapted for use in a controlled area such as retail store and employing multi-frequency resonant tag circuit having distinct frequencies detection discrimination. electromagnetic field is provided within the at frequency which swept through range including of circuit. In presence area, pulses are detected by receiver includes noise rejection circuitry discrimination true signals from noise. The sensitive to expected operative discriminate fromnoise on basis several different criteria, resulting substantially reduced false alarm actuation.