Pulsed electronic article surveillance device employing expert system techniques for dynamic optimization

An electronic article surveillance system, comprising:

• (a) transmitter means operable for generating a magnetic field in a surveillance area;
• (b) a receiver having a plurality of receiving coils and operable, upon detection of an electronic article surveillance tag, to implement a validation sequence on a succession of signals received by the receiving coil which provided the signal giving rise to said detection;
• and
• (c) control means for operating said transmitter means and said receiver means, said control means having facility for varying the number of cycles in said validation sequence.

An electronic article surveillance system, comprising:

• (a) transmitter means operable at a fundamental frequency for generating a magnetic field in a surveillance area;
• (b) a receiver for detection of electronic article surveillance tags;
• and
• (c) control means for operating said transmitter means with a frequency hopping between frequencies respective above and below said fundamental frequency.

An electronic article surveillance system, comprising:

• (a) transmitter means operable for generating a magnetic field in a surveillance area;
• (b) a receiver having a plurality of receiving coils and operable, upon detection of an electronic article surveillance tag, to implement a validation sequence on a succession of signals received by the receiving coil which provided the signal giving rise to said detection;
• and
• (c) control means for operating said transmitter means in one cycle of said validation sequence to transmit energy at a frequency at which a deactivated electronic article surveillance tag is resonant.

An electronic article surveillance system, comprising:

• (a) transmitter means operable for generating a magnetic field in a surveillance area;
• (b) a receiver having noise environment analysis means and operable, upon detection of an electronic article surveillance tag, to implement a validation sequence on a succession of signals received thereby;
• and
• (c) control means for establishing the number of cycles in said validation sequence adaptively to the noise environment determined by said noise environment analysis means.