Abstract:
A communication system (10) receiving a communication signal from a far communication system (12) has a channel selector, and a number of local transceivers (22) forming a first broadcast array and a second channel searching array. The first broadcast array is configured to receive the communication signal and transmit a local communication signal on channels . Each local transceiver is connected to a controller (32) . The controller is configured to remove noise from the far communication signal . The noise includes interference from the local transceivers being received on the channel. The controller measures a parameter of at Least one of the channels. The controller determines an availability of one or some channels using the second channel searching array. The second channel searching array outputs an available channel signal to the controller. The controller (32) communicates the availability to at least one of the first broadcast array to transmit and to receive the far communication signal on the available channel.
Abstract:
In an electronic article surveillance system (24), quadrature transmitting and receiving antennas are used to improve field distribution. A transmitting antenna arrangement includes first and second adjacent co-planar antenna loops (42, 44) and excitation circuitry (46) for generating respective alternating currents in the first and second loops such that the respective alternating currents are 90 DEG out of phase. In a receiving arrangement (300), respective signals received from two adjacent co-planar antenna loops (302, 304) are respectively phase-shifted by +45 DEG and -45 DEG , and the resulting phase-shifted signals are summed. A far-field canceling transmitting antenna arrangement includes four loops (66', 78, 68, 70) operated at phases of 0 DEG , 90 DEG , 180 DEG and 270 DEG respectively. All four loops may be co-planar, with any bucking vertical segments being horizontally displaced from each other. Alternatively, the 0 DEG and 180 DEG loops may also be arranged in a common plane that is close to and parallel with another plane in which the 90 DEG and 270 DEG loops are arranged.
Abstract:
A product tag system comprises: an RFID tag adapted for attachment to a product; a data store in the tag for bar code information relating to the product; a tag detacher for removing the tag from the product at a point of sale; an RFID tag reader for retrieving the bar code information from the tag when the tag is placed in the tag detacher; and, an display for presenting the bar code information in a form which can be scanned by a conventional bar code scanner, and/or in human readable form. A method for monitoring products comprise the steps of: attaching an RFID tag to a product; writing bar code information onto the tag; retrieving the bar code information from the tag at a point of sale; displaying the bar code information in a form which can be scanned by a conventional bar code scanner, and/or in human readable form; and, detaching the tag from the product.