摘要:
The present invention is directed to an illumination source (10) for illuminating an object (11) with light (16) of substantially constant intensity. The illumination source includes an electric light bulb (12) which is supplied with voltage from an adjustable- voltage power supply (14). The voltage supplied by the power supply (14) varies in accordance with the intensity of the light (16) radiated from the bulb (12), as sensed by a photodiode (24). The photodiode (24) is separated from the bulb by a length of lightguide fiber (26) into which light from the bulb is coupled by a glass rod (28). The fiber (26) and the rod (28) allow the photodiode (24) to be supplied with light from the bulb (12), yet to be thermally insulated therefrom, so as to avoid thermal run-away of the diode.
摘要:
An RFID system with a plurality of tags and base stations where transmission of information to a specific tag is carried out by one of the base stations, where said one of the base stations is selected based on location of the tag relative to the plurality of the base stations; illustratively, by the base stations that is closest to the tag.
摘要:
A circuit board, for use with a high speed backplane, includes transmitter and receiver with circuitry for correcting for multipath signal errors. A training sequence that is often a pseudo-random signal is transmitted by the transmitter on a first circuit board to a receiver located on a second circuit board. The receiver on the second circuit board includes an analog-to-digital signal converter, an equalizer, and a binary digital-to-analog reconverter for receiving the training sequence. The equalizer preferably comprises a series of connected registers having taps in between, a plurality of individual weighting means attached to each of the taps, and a summing means connected to the weighting means. A training sequence is transmitted from the first circuit board to the receiver on the second circuit board, enabling the receiver to adaptively determine a set of weighting means coefficients for correcting the multipath errors in subsequent signals. Coefficients for the weighting means are then adjusted from the output of the summing means. The method and system described can substantially reduce the cost of backplane fabrication and enhance the performance of the overall system.
摘要:
Systems for determining a location of a portable device are provided. The system includes stationary infrared (IR) base stations, portable devices and at least one radio frequency (RF) transceiver. At least two of the IR base stations receive timing synchronization information and transmit corresponding IR location codes in a time period based on the received timing synchronization information. Each IR location code is representative of a location of the corresponding IR base station. Each portable device detects the IR location codes and, if one of the IR location codes is detected, transmits an output signal including a portable device ID representative of the portable device and the detected IR location code. The RF transceiver periodically provides, upon a request, the timing synchronization information to the respective IR base stations relative to a unified time of origin.
摘要:
An RFID system with a plurality of tags and base stations where transmission of information to a specific tag is carried out by one of the base stations, where said one of the base stations is selected based on received signal power of the tag relative to the plurality of the base stations.
摘要:
Methods and systems for locating a portable device in an enclosure having a location defining a virtual wall are provided. The system includes first and second infrared (IR) transmitters directed to opposite sides of the virtual wall. Each of the transmitters is configured to selectively transmit an interfering IR signal (IIS) and a data signal including a corresponding transmitter location ID.
摘要:
An RFID system with a plurality of tags and base stations where transmission of information to a specific tag is carried out by one of the base stations, where said one of the base stations is selected based on received signal power of the tag relative to the plurality of the base stations.
摘要:
A content navigation method that may be used with a storage device that holds multiple content objects includes a controller, at least one search switch and at least one control switch. Each of the content objects has a corresponding name which includes at least one character from an alphabet. The controller determines a set of names of the stored content that corresponds to the activation of the search switch, displays at least one name the set of names and, responsive to the control switch, selects the content object corresponding to the displayed name. The search switches may include multiple search switches, each associated with a predetermined set of letters from the alphabet. Alternatively, each switch may have an corresponding display and may be associated with a dynamically determined set of letters based on their frequency of occurrence in the names.
摘要:
A base station that uses an antenna assembly and associated signal processing where the antenna assembly includes at least one directional antenna, developing information from which a determination is made regarding the direction from which a received signal is coming. By employing a plurality of such base stations the location of a transmitting tag is ascertained.
摘要:
A method for correcting the phase and amplitude imbalance of a quadrature modulated RF signal requires that errors be induced in both amplitude, &rgr;, and in phase &phgr; in at least three different combinations in order to determine the appropriate correction value for amplitude and phase offsets &Dgr; and &thgr;e. According to a first embodiment the same &rgr; and &phgr; offsets applied in three different combinations to determine the necessary &Dgr; and &thgr;e corrections. According to a second embodiment, a fourth measurement is made in order to determine an unknown control scale factor for balance adjustments.