Abstract: Certain aspects and features of the present disclosure relate to a system that improves the localization and interrogation of RFID tags in an environment with many tags. Suppression antennas are used to create suppression zones around large background tag populations around or near the portal. The suppression antennas quiet the tags in a suppression zone to prevent erroneous tracking of these tags at nearby RFID portal antennas. Optionally, a suppression RFID reader can communicate with neighboring readers, including a portal RFID reader, to provide information that can be used for expedited tracking of a tag that may be approaching an RFID portal.

Abstract: Aspects and features of this disclosure include operating an RFID reader to identify targeted tags and background tags from among a population of RFID tags. The background tags are then monitored by reading the background tags at a background rate and the targeted tags are tracked by reading the targeted tags at an enhanced rate. The enhanced rate is significantly greater than the background rate. The tags from a large population can be segregated into the two subpopulations based on read measurements stored in a tag database. A tag may become “targeted” by moving towards or appearing near a portal of interest. Tag detection, and therefore an alarm message or some other desired result, can be provided quickly due to the higher, enhanced read rate being applied to the targeted tags.

Abstract: Aspects and features of this disclosure include a radio frequency identification (RFID) antenna multiplexer. An RFID reader and an RFID system using the RFID antenna multiplexer are also disclosed. The multiplexer includes multiple output ports. Each of at least some of the output ports is connectable to an antenna or another device. In some aspects, a logic circuit in the multiplexer is configured to cause a radio frequency (RF) switch to select an output port from the multiple output ports to connect to the input port based upon a reduction in RF power at the input port. In some aspects, the multiplexer includes an energy harvester connected to the input port to harvest signal energy from the RFID reader and a storage device connected to the energy harvester to store the signal energy and supply power to the multiplexer using the signal energy.

Abstract: Aspects and features of this disclosure include a radio frequency identification (RFID) antenna multiplexer. An RFID reader and an RFID system using the RFID antenna multiplexer are also disclosed. The multiplexer includes multiple output ports. Each of at least some of the output ports is connectable to an antenna or another device. In some aspects, a logic circuit in the multiplexer is configured to cause a radio frequency (RF) switch to select an output port from the multiple output ports to connect to the input port based upon a reduction in RF power at the input port. In some aspects, the multiplexer includes an energy harvester connected to the input port to harvest signal energy from the RFID reader and a storage device connected to the energy harvester to store the signal energy and supply power to the multiplexer using the signal energy.

Abstract: An RF system using amplitude modulation (AM) with orthogonal offset is disclosed. The orthogonal offset generator can shift the AM signal trajectory away from the origin while maintaining the time domain requirements for an RFID signal, such as waveform edge rise and fall times. In some embodiments stored waveforms incorporating the controlled orthogonal offset are used to synthesize a sequence of symbols. The stored waveforms may also include nonlinear and/or linear predistortion to reduce computational complexity. The waveforms can be represented in Cartesian coordinates for use in a direct conversion transmitter or polar coordinates for use in a polar modulation transmitter. An RFID system can also include a receiver to receive incoming RFID signals.

Abstract: Methods, systems, and computer readable media for distribution of time synchronization information to ultra-wide-band (UWB) devices are disclosed. A system includes anchors and tags having synchronized timing systems. The system includes a site master configured for transmitting a first time-synchronization message to at least a first anchor. The first anchor is configured for distributing time synchronization information to at least a second anchor by transmitting a first UWB message during an assigned time slot for the first anchor. The first UWB message includes timing information based on the first time-synchronization message.

Abstract: Apparatus and method embedding a camera in a street light includes structure and/or function whereby the street light has a first compartment having an LED array configured to illuminate an area beneath the street light. A second compartment is coupled to the first compartment and has a camera directed toward the area beneath the street light. A third compartment is coupled to the second compartment and is configured to attach the street light to a vertical support. A passive air channel is disposed between the first compartment and the second compartment, and is configured to direct air from beneath the street light to the top of the street light. Preferably, the power supply for the LED array is disposed in a compartment different than the first compartment.

Abstract: A polar transmitter for an RFID reader and a system using the polar transmitter are disclosed. An RFID system according to at least some embodiments of the invention includes a polar transmitter, a receiver to receive responses from RFID tags, and a coupler connected to the polar transmitter, the receiver and one or more antennas. In at least some embodiments, the polar transmitter of the RFID system includes an envelope amplifier with a multi-phase buck converter to provide an envelope signal and a phase modulator connected to a power amplifier to phase modulate the power amplifier using a phase signal. In at least some embodiments, the polar transmitter of the RFID system transmits OPR-ASK signals to reduce AM modulation depth and provide a continuous phase signal for the phase modulator.

Abstract: Methods, systems, and computer readable media for time-slotted ultra-wide-band (UWB) object tracking are disclosed. A system includes anchors and tags having synchronized timing systems. The anchors are configured for performing time-slotted UWB ranging during time windows, one for each tag. During each window, the anchors sequentially transmit UWB transmissions in designated time slots, one for each anchor, as specified by an order of operation. The anchors receive responsive UWB transmissions from the tag assigned to the time window and determine time-of-flight measurements for the responsive UWB transmissions.

Abstract: A polar transmitter for an RFID reader and a system using the polar transmitter are disclosed. An RFID system according to at least some embodiments of the invention includes a polar transmitter employing a switch mode power amplifier. The system can also include a receiver to receive responses from RFID tags and a coupler connected to the polar transmitter, the receiver and one or more antennas. In at least some embodiments, the polar transmitter of the RFID system includes an envelope amplifier connected to the switch mode power amplifier to provide an envelope signal and a phase modulator connected to the switch mode power amplifier to phase modulate the switch mode power amplifier using a phase signal. In at least some embodiments, the polar transmitter of the RFID system transmits OPR-ASK signals to reduce AM modulation depth and provide a continuous phase signal for the phase modulator.

Abstract: An RF system using amplitude modulation (AM) with orthogonal offset is disclosed. The orthogonal offset generator can shift the AM signal trajectory away from the origin while maintaining the time domain requirements for an RFID signal, such as waveform edge rise and fall times. In some embodiments stored waveforms incorporating the controlled orthogonal offset are used to synthesize a sequence of symbols. The stored waveforms may also include nonlinear and/or linear predistortion to reduce computational complexity. The waveforms can be represented in Cartesian coordinates for use in a direct conversion transmitter or polar coordinates for use in a polar modulation transmitter. An RFID system can also include a receiver to receive incoming RFID signals.

Abstract: An RF system using PR-ASK with orthogonal offset is disclosed. In some embodiments, the system includes a PR-ASK signal generator and an orthogonal offset generator. The PR-ASK signal generator can produce a signal representing a sequence of symbols, for example, RFID symbols. The orthogonal offset generator can shift the PR-ASK signal trajectory away from the origin while maintaining the time domain requirements for an RFID signal, such as waveform edge rise and fall times. In some embodiments stored waveforms incorporating the controlled orthogonal offset are used to synthesize a sequence of symbols. The stored waveforms may also include nonlinear and/or linear predistortion to reduce computational complexity. The waveforms can be represented in Cartesian coordinates for use in a direct conversion transmitter or polar coordinates for use in a polar modulation transmitter. An RFID system can also include a receiver to receive incoming RFID signals.

Abstract: A radio frequency (RF) object detector is disclosed. The RF object detector in example embodiments transmits an RF signal. A receiver measures the amplitude, the phase, or both the amplitude and phase of the signal as reflected from objects in an interrogation zone. The RF object detector can be deployed in a combined system that performs multiple functions. For example, the RF object detector can be integrated with an EAS system that also sends RFID commands and receives RFID responses. In some embodiments the object detector can discriminate between moving objects and stationary objects, and/or discriminate between objects in the interrogation zone and objects outside the interrogation zone, and/or provide location estimates. An antenna or antennas can be connected in a mono-static or bi-static configuration and the phase and/or amplitude signals can be either DC-coupled or AC-coupled into the system through a mixer.

Abstract: An AC-coupled RFID system is disclosed. Embodiments of the invention statistically correlate the transmit data from a baseband transmit signal and the receive data in a receive signal after the signal has passed through a baseband receive filter. By using a receive bandpass or high-pass filter at baseband, the receiver can be AC-coupled in the baseband. This AC coupling significantly reduces cost and complexity by eliminating high-power reflected signals at and near DC. The high-pass corner frequency of the receive filter passes enough of the receive signal to still be measurable. The correlation is used to estimate the reflected carrier, which in turn enables cancellation of the carrier, improving RFID reader sensitivity.

Abstract: A radio frequency (RF) metal detector and an electronic article surveillance (EAS) system are disclosed. The RF metal detector in example embodiments transmits an RF signal. A receiver measures the power and phase of the signal as reflected from metallic objects in an interrogation zone. The RF metal detector can be deployed in a combined system that performs multiple functions. For example, the RF metal detector can be integrated with an EAS system that also sends RFID commands and receives RFID responses. In some embodiments the metal detector can discriminate between moving metal objects and stationary metal objects, and/or discriminate between objects in the interrogation zone and objects outside the interrogation zone. An antenna or antennas can be connected in a mono-static or bi-static configuration and the phase and power signals can be either DC-coupled or AC-coupled into the system through a mixer.

Abstract: An AC-coupled RFID system is disclosed. Embodiments of the invention statistically correlate the transmit data from a baseband transmit signal and the receive data in a receive signal after the signal has passed through a baseband receive filter. By using a receive bandpass or high-pass filter at baseband, the receiver can be AC-coupled in the baseband. This AC coupling significantly reduces cost and complexity by eliminating high-power reflected signals at and near DC. The high-pass corner frequency of the receive filter passes enough of the receive signal to still be measureable. The correlation is used to estimate the reflected carrier, which in turn enables cancellation of the carrier, improving RFID reader sensitivity.

Abstract: A radio frequency (RF) object detector is disclosed. The RF object detector in example embodiments transmits an RF signal. A receiver measures the amplitude, the phase, or both the amplitude and phase of the signal as reflected from objects in an interrogation zone. The RF object detector can be deployed in a combined system that performs multiple functions. For example, the RF object detector can be integrated with an EAS system that also sends RFID commands and receives RFID responses. In some embodiments the object detector can discriminate between moving objects and stationary objects, and/or discriminate between objects in the interrogation zone and objects outside the interrogation zone, and/or provide location estimates. An antenna or antennas can be connected in a mono-static or bi-static configuration and the phase and/or amplitude signals can be either DC-coupled or AC-coupled into the system through a mixer.

Abstract: A method of creating a tag or an attribute in a markup language document, the method including receiving information in an editable area of an interface and creating the tag or the attribute based on the received information.

Abstract: A method for assigning at least one event to an action in a markup language environment.

Abstract: A method of editing an extensible markup language (XML) document, the method including receiving user input in an editable field and automatically correcting the user input.