Abstract: Methods of compensating for position errors due to signal scaling, linearity, and offset between first and second members in a displacement transducer are provided, including: producing a first signal at the first member; producing a second signal at the first member; modulating the first signal at the second member to include at least one region with an invariant amplitude as the first and second members are displaced relative to one another along a measurement axis; determining a relation between a sample of the second signal and the invariant amplitude of the first signal as an indication of an error parameter; and generating a compensated sample based upon the determined relation.

Abstract: Methods of compensating for position errors due to signal scaling, linearity, and offset between first and second members in a displacement transducer are provided, including: producing a first signal at the first member; producing a second signal at the first member; modulating the first signal at the second member to include at least one region with an invariant amplitude as the first and second members are displaced relative to one another along a measurement axis; determining a relation between a sample of the second signal and the invariant amplitude of the first signal as an indication of an error parameter; and generating a compensated sample based upon the determined relation.

Abstract: Disclosed are embodiments of methods, systems, and apparatus for ranging or determining a distance between a reader and a wireless tag. In one embodiment, a query signal is transmitted from the reader to the wireless tag. The carrier signal from the reader may then be modulated and the modulated signal transmitted from the reader during at least a portion of a response period for the wireless tag. A modulated backscatter response from the wireless tag is received at the reader is used to calculate a distance between the reader and the wireless tag.

Abstract: In an embodiment there is an electronic tag having an encoded bit data pattern in a portion of a data field from the tag resulting in a modulated backscatter signal from the tag when the tag responds to a read command from an interrogator. In an embodiment there is a method for determining the range between an antenna of an interrogator and an electronic tag comprising the steps of: 1) singulating an electronic tag of interest; 2) sending a range command to the electronic tag of interest; 3) detecting a modulated backscatter response from the electronic tag of interest; 4) measuring a time delay between a transmitted modulated carrier signal from the interrogator and the modulated backscatter response; 5) calculating a distance between the antenna and the electronic tag using the time delay; and 6) reporting the distance.

Abstract: An apparatus and method for controlling and/or reducing power consumption in an electronic tag reader (e.g. RFID). One preferred method includes the steps of configuring an automatic inventory command for excluding features; adjusting a search order for singulating RFID tags; activating a trigger control of the RFID reader for engaging power to begin reading the RFID tags; having the poll the RFID tags at a frequency for identifying said tags and hop to another frequency when the RFID tags are not located; the reader then terminating the reading after an interval when there are no new tags or when other criteria are met without the user deactivating the trigger control.

Abstract: A portable, multi-mode RFID reader is capable of operating in a plurality of interrogation modes. The reader includes a processor configured to select either a subset of the plurality of interrogation modes according to which the RFID reader will operate when interrogating a set of one or more RFID tags, a sequence in which at least some of the plurality of interrogation modes are employed when the RFID reader interrogates the set of RFID tags, or both. Configuration of the processor as described is such that the RFID reader may consume less power, interrogates the set of one or more RFID tags more quickly, or both consume less power and interrogate the set of one or more RFID tags more quickly.

Abstract: Disclosed are embodiments of methods, systems, and apparatus for singulating wireless tags. In one embodiment, a power ramping method is provided for tag singulation. This embodiment involves activating a control of an RFID reader for engaging power to begin reading RFID tags. The first reading is taken at a relatively low transmitting power level. If an RFID tag is not detected at the first power level, the power from the RFID reader is increased to a second higher power level. Increasing the transmitting power may be repeated until there is a final read volume where a single RFID tag, or a select number of such tags, is detected. Certain embodiments may provide for ramping the power down as well as up, so that if multiple tags are detected and only the closest tag is desired to be detected, tags can be excluded systematically from the read volume until only a single tag remains.

Abstract: A system and method for providing operational feedback of systems employing electronic tags such as radio frequency identification (RFID) tags. In one configuration, the RFID reader is actuated by a single trigger pull, with the reader continuing to read multiple RFID tags in the read zone as long as the trigger is held until a terminating event occurs and in another configuration, an apparatus and method provides real-time feedback of the progress of a multiple RFID tag reading operation.

Abstract: A preferred embodiment is directed to a method of RFID power ramping for tag singulation that includes activating the trigger control of an RFID reader for engaging power to begin reading RFID tags. A user may take a first reading at a low power level of a volume around the RFID reader establishing a first read volume. If the user does not detect a particular RFID tag, the user may then increase the transmitting power from the RFID reader to a second higher power level obtaining a second reading of RFID tags in a second read volume. The user may once again increase the transmitting power from the RFID reader to a third higher power level obtaining a third reading of RFID tags in a third reading volume. Increasing the RFID transmitting power is repeated until there is a final read volume where the operator reads and recognizes the detected RFID tag. The final step includes deactivating the trigger control of the RFID reader after reading the desired RFID tag.