Abstract: An object identification system includes a monitor and a plurality of transceivers that communicate over a common medium. The monitor includes a first transmitter, a first receiver, and a processor. Each transceiver includes a resonant circuit, a transmitter, a receiver, and an antenna coupled to the resonant circuit. The processor performs a method for performing transceiver communication that includes the steps of: (a) transmitting from the first transmitter a first frequency for a first duration; (b) after lapse of the first duration, receiving via the first receiver a response signal from at least one of the resonant circuits; (c) determining a second frequency from the received response signal; and (d) performing transceiver communication using the second frequency.

Abstract: An object identification system includes a monitor and a plurality of transceivers that communicate over a common medium. The monitor includes a first transmitter, a first receiver, and a processor. Each transceiver includes a resonant circuit, a transmitter, a receiver, and an antenna coupled to the resonant circuit. The processor performs a method for performing transceiver communication that includes the steps of: (a) transmitting from the first transmitter a first frequency for a first duration; (b) after lapse of the first duration, receiving via the first receiver a response signal from at least one of the resonant circuits; (c) determining a second frequency from the received response signal; and (d) performing transceiver communication using the second frequency.

Abstract: An object identification system includes a monitor and a plurality of transceivers that communicate over a common medium. The monitor includes a first transmitter, a first receiver, and a processor. Each transceiver includes a resonant circuit, a transmitter, a receiver, and an antenna coupled to the resonant circuit. The processor performs a method for performing transceiver communication that includes the steps of: (a) transmitting from the first transmitter a first frequency for a first duration; (b) after lapse of the first duration, receiving via the first receiver a response signal from at least one of the resonant circuits; (c) determining a second frequency from the received response signal; and (d) performing transceiver communication using the second frequency.

Abstract: A grid consists of a first serpentine, and a second serpentine overlapping the first serpentine. Signals from the first and second serpentines are analyzed to determine transducer position. The first and second serpentines are foldback serpentines. The first serpentine is offset from the second serpentine by approximately ninety degrees.

Abstract: An object identification system includes a monitor and a plurality of transceivers that communicate over a common medium. The monitor includes a first transmitter, a first receiver, and a processor. Each transceiver includes a resonant circuit, a transmitter, a receiver, and an antenna coupled to the resonant circuit. The processor performs a method for performing transceiver communication that includes the steps of: (a) transmitting from the first transmitter a first frequency for a first duration; (b) after lapse of the first duration, receiving via the first receiver a response signal from at least one of the resonant circuits; (c) determining a second frequency from the received response signal; and (d) performing transceiver communication using the second frequency.

Abstract: An object identification system includes a monitor and a plurality of transceivers that communicate over a common medium. The monitor includes a first transmitter, a first receiver, and a processor. Each transceiver includes a resonant circuit, a transmitter, a receiver, and an antenna coupled to the resonant circuit. The processor performs a method for performing transceiver communication that includes the steps of: (a) transmitting from the first transmitter a first frequency for a first duration; (b) after lapse of the first duration, receiving via the first receiver a response signal from at least one of the resonant circuits; (c) determining a second frequency from the received response signal; and (d) performing transceiver communication using the second frequency.

Abstract: A monitoring system incorporates antennas that transmit signals at predetermined frequencies; the transmitted signals are received by tags located in the active monitoring area of the antenna which then transmit signals back to the antenna. The antennas are tuned to each desired frequency prior to driving the antennas to transmit at the desired frequency. The system transmits a range of frequencies in a sequence that uses overlapping frequency steps. The monitoring system is also constructed having a variable configuration resulting in the ability to be reconfigured under program control to conform to varying system requirements. The integrated monitoring system employs programmable formats for reconfiguration such that upon program input from a host computer the system can assume predetermined configurations to conform to the particular tasks for the specific application.

Abstract: A grid consists of a first serpentine, and a second serpentine overlapping the first serpentine. Signals from the first and second serpentines are analyzed to determine transducer position. The first and second serpentines are foldback serpentines. The first serpentine is offset from the second serpentine by approximately ninety degrees.

Abstract: An object identification system includes a monitor and a plurality of transceivers that communicate over a common medium. The monitor includes a first transmitter, a first receiver, and a processor. Each transceiver includes a resonant circuit, a transmitter, a receiver, and an antenna coupled to the resonant circuit. The processor performs a method for performing transceiver communication that includes the steps of: (a) transmitting from the first transmitter a first frequency for a first duration; (b) after lapse of the first duration, receiving via the first receiver a response signal from at least one of the resonant circuits; (c) determining a second frequency from the received response signal; and (d) performing transceiver communication using the second frequency.

Abstract: A carrier, as used for example to transport several radio frequency identification devices, includes a circuit having an antenna and a series capacitor for tuning the antenna. Enhanced transceiver communication results when transceivers are placed in the carrier. Alternately, a carrier may include first and second antenna circuits, each having a capacitor for tuning the respective antenna. The two circuits may cooperate so that energy received in a first pattern is re-radiated in a second pattern for further enhanced transceiver communication, such as detection of the presence of the RFID device within the carrier.

Abstract: A position resolving system is described incorporating a cordless pointing instrument such as a pen having an oscillator and battery supply therein. Electromagnetic radiations from the pen are directed onto a tablet grid having a plurality of grid loops therein. When the pen is in contact with the tablet, signals of maximum amplitude are radiated; when the pen is raised out of contact with the tablet, signal radiation is maintained but at a decreased amplitude for a predetermined time and then reduced to zero. Each loop is formed of parallel conductors joined at one end thereof by an end conductor; each loop is placed adjacent corresponding loops in the X and in the Y directions. The electromagnetic radiations are non-coherently amplitude detected to select the grid loop in the X direction and the grid loop in the Y direction having the maximum amplitudes thereon.

Abstract: A graphic tablet and method is described having a plurality of orthogonally related sensing conductors imbedded in the surface of a tablet. The imbedded sensing conductors thus form an X and Y grid for receiving signals from a signal radiating pen. The signals induced in the imbedded sensing conductors are detected, operated upon, and digitized to form an address of the radiating pen. The sensing conductors are formed of three conductors for each of the X and Y directions; the conductors extend across the pad in a given direction and are then redirected back across the pad in the opposite direction. Each of the X and Y sensing conductors thus extend back and forth across the pad forming parallel adjacent segments. A plurality of auxiliary conductors are each connected through resistors to a respective sensing conductor at spaced points along the sensing conductors length. Signals induced in the sensing conductor thus result in auxiliary signals in the auxiliary conductor.

Abstract: A writing tablet system is disclosed incorporating a plurality of parallel conductors imbedded beneath the surface thereof arranged in two groups in orthogonal relationship with respect to each other. The conductors form an antenna grid for receiving radiated electric signals generated remote from the tablet and supplied to a pen, or cursor, acting as a signal radiating means. The radiated signals generate signals of varying amplitude in the respective grid conductors. Each of the conductors in each of the X and Y directions are interconnected at one end thereof by resistances. The opposite ends of each of the conductors are either connected to a signal sensing circuit or are left unconnected. The unconnected conductors, or minor conductors, are arranged between the connected (or major) conductors such that radiated signals received by the antenna grid are received by all conductors but only those signals appearing on the major conductors are utilized in the determination of pen position.

Abstract: A writing tablet is disclosed incorporating a plurality of conductors imbedded beneath the surface thereof in orthogonal relationship with respect to each other. The conductors form a grid for receiving radiated electric signals generated remote from the tablet and supplied to a pen acting as a radiating antenna. The radiated signals generate signals of varying amplitude in the respective grid conductors; the grid conductors in each of the X and Y directions are interconnected by resistors; terminals are provided at the outside conductors in the X and Y directions. The terminals are sequentially connected to a detector which in turn provides input signals to a dual slope integrator for ratioing the amplitude of the signal appearing at selected terminals. The output of the integrator is a timed wave form having a time value proportional to the position of the pen on the tablet surface.

Abstract: A method and apparatus are provided for converting a position of a pen to a digital number representing the pen position with respect to a grid of conductors. A coil disposed above the tip of the pen is driven by a continuous AC input voltage of fixed frequency and amplitude, thereby inducing corresponding signals in each of the conductors of the grid. Scanning circuitry sequentially scans the grid conductors, first in the X direction and then in the Y direction, thereby sequentially coupling the induced signals to the input of a differential amplifier. A position counter is reset at the beginning of scanning in each direction and is incremented at a rate proportional to and greater than the scanning rate. The outputs of the differential amplifier are inputted to a phase sensitive detector producing a characteristic output which changes polarity as grid conductors on opposite sides of the pen tip location are sequentially scanned.