摘要:
A master entity is capable of broadcasting commands to slaves which move to another state when they satisfy a primitive condition specified in the command. By moving slaves among three sets, a desired subset of slaves can be isolated in one of the sets. This desired subset of slaves ten can be moved to one of the states that is unaffected by commands that cause the selection of other desirable subsets of slaves. In the incorporated U.S. Pat. Nos. 5,550,547 and 5,673,037, certain subgroups of radio frequency tags are selected for querying, communicating, and/or identifying by commands from a base station.
摘要:
A multistage voltage multiplying circuit for single chip passive RF tags is provided, wherein the parasitic capacitance of the diodes of each stage of the voltage multiplying circuit is much less than the parasitic capacitance of the diodes of the preceding stage.
摘要:
An apparatus, method, and system are provided for sending radio frequency (RF) power to RF transponders (RFID tags), wherein the frequency sent to the tags is changed very rapidly.
摘要:
The present invention assures the integrity of state information retained by a Radio Frequency Transponder during a loss of power. During the regular operation of the Transponder power is provided to a voltage-storing device powering an information retention mechanism of the Transponder. After the loss and reestablishing of power to the Transponder but before the Transponder is restarted, the voltage-storing device is checked to determine whether sufficient power is present in the information retention mechanism to retain information without corruption. If sufficient power is present, a signal to indicate that fact is communicated to the Transponder and the stored information is restored. The Transponder is then restarted.
摘要:
A method of selecting groups of radio frequency RF transponders (tags) for communication between a base station and the tags. The tags are selected into groups according to a physical attribute of the signal sent by the tags to the base station, or according to the physical response of the tags to a physical attribute of the signal sent from the base station to the tags. Communication with the tags is thereby simplified, and the time taken to communicate with the first tag is markedly reduced.
摘要:
Communication of information between the inside and the outside of an electrically conducting enclosure is performed through the use of a frequency selective surface on the electrically conducting enclosure, which permits passage of electromagnetic waves at particular frequencies, but prohibits waves of other frequencies from penetration. Thus, one or more objects contained within the electrically conducting enclosure, which include radio frequency tags attached to the objects containing information about the objects, may be monitored or interrogated by the transmission of an electromagnetic wave at the permitted frequency through the frequency selective surface. With such a system, control and inventory of enclosed objects may be performed while the EMI shielding function of the electrically conducting enclosure is maintained.
摘要:
The present invention is a magnetic sensor used with one or more frequency band pass filters and a logic circuit that produces a ("critical") signal that is used for enabling and disabling an external electronic circuit, e.g. a computer circuit. The magnetic sensor produces a signal when excited by an externally applied alternating current (ac) magnetic field. The external ac magnetic field can comprise one or more frequencies, each of which induces an electrical signal at the respective frequency in the sensor. Depending on the linearity of the sensor, one or more harmonic frequencies of the signal frequencies can also be induced in the sensor. One or more bandpass filters is connected to the magnetic sensor and each of the bandpass filters is tuned to filter the signal to select filtered signals, from the output of the sensor. A logic circuit is activated by one or more of the filtered signals or a combination of one or more of the signal frequencies. When the logic circuit is activated, a critical signal is applied to an electronic circuit to enable or disable the external electronic circuit.
摘要:
A multistage voltage multiplying circuit for single chip passive RF tags is provided, wherein the parasitic capacitance of the diodes of each stage of the voltage multiplying circuit is much less than the parasitic capacitance of the diodes of the preceding stage.
摘要:
A Write Broadcast system and method uses a base station to write sent data to all or some selected number (sub group) of tags in a base station field simultaneously. By unselecting the tags that have been successfully written to, and requesting a response from the remaining tags in the field (or sub group), the system determines, by receiving a response to the request, that there are tags in the field (sub group) that were unsuccessfully written to. Another Write Broadcast signal is sent to these tags. The system is useful for quickly (simultaneously) “stamping” information on the tag memory of a large number of tags in the field of the base station.
摘要:
Processes and apparatus for manufacturing radio frequency transponders having substrates formed from a flexible tape or film are disclosed. The RF transponders are formed on the tape so that their longest dimension (e.g., their length ("L")) is oriented parallel to the length of the tape. This layout places few or no constraints in the transponder's length allowing the length of the transponder's antenna circuit to be adjusted to satisfy the requirements of various applications.