Abstract: According to the invention, a system and method of reducing noise interference in a way that employs pseudorandom coding. A transmitter and receiver are provided to send and receive a string of non-periodic pulses. The string of non-periodic pulses can be a sequence of pseudorandom codes. The random transmission of pulses in a non-periodic manner promotes a significant immunity to periodic interferences of constant noise operating in a surveillance area. The string of non-periodic pulses can be mutually spaced and binary, in the form of 0 or 1, and can include several bits per cycle to measure the mean and standard deviation of the string of non-periodic pulses received. A circuit is coupled to the transmitter and receiver for comparing the portion of the string of non-periodic pulses received with the string of non-periodic pulses transmitted; and whereby an alarm in triggered if the portion of the string of non-periodic pulses is above a threshold value.
Type:
Grant
Filed:
September 4, 2002
Date of Patent:
June 15, 2004
Assignees:
WG Security Products, Inc., EAS Sensor Sense
Abstract: According to the invention, a system and method of reducing noise interference in a way that employs pseudorandom coding. A transmitter and receiver are provided to send and receive a string of non-periodic pulses. The string of non-periodic pulses can be a sequence of pseudorandom codes. The random transmission of pulses in a non-periodic manner promotes a significant immunity to periodic interferences of constant noise operating in a surveillance area. The string of non-periodic pulses can be mutually spaced and binary, in the form of 0 or 1, and can include several bits per cycle to measure the mean and standard deviation of the string of non-periodic pulses received. A circuit is coupled to the transmitter and receiver for comparing the portion of the string of non-periodic pulses received with the string of non-periodic pulses transmitted; and whereby an alarm in triggered if the portion of the string of non-periodic pulses is above a threshold value.
Type:
Application
Filed:
September 4, 2002
Publication date:
December 18, 2003
Applicants:
WG Security Products, Inc., EAS Sensor Sense
Abstract: An antenna system for an electronic article surveillance system, comprising: a first antenna and a second antenna, the first antenna and the second antenna mounted for use in a substantially overlapping manner, the first antenna configured as a loop, the second antenna configured in a “figure-8”; a control circuit for selectively activating one of the first and second antennas. The first and second antennas each operate as a transmit and receive antenna. The control circuit further comprises a switch to selectively enable operation of one of the antennas when the other is open circuit. One of the antennas transmits and receives while the other is open circuit, and vice versa. The loop antenna substantially detects markers oriented substantially perpendicular to an elongated axis when entering into a surveillance area. The “figure-8” antenna substantially detects markers oriented substantially parallel to an elongated axis when entering into a surveillance area.
Type:
Application
Filed:
September 4, 2002
Publication date:
October 23, 2003
Applicants:
WG Security Products, Inc., EAS Sensor Sense