Abstract:
The present invention overcomes the problems discussed above by providing a linearizer apparatus for providing a linear ramp modulation for a voltage control oscillator (VCO), including voltage controlled oscillator means (VCO) having input and output terminals, and means for producing the output signal at its output terminal at the output frequency such that the output frequency corresponds to the voltage of a modulated tuning signal applied to the input terminal. A signal division means is coupled to the output of the VCO for producing a divided signal. A glass bulk acoustic delay means is coupled to the signal division means for producing a delayed signal. A first comparison signal generator means is coupled to the divided signal and the delayed signal for producing an IF signal which is proportional to the VCO output signal non-linearities. A reference oscillator means is provided for producing a reference signal. A second comparison signal generator means is coupled to the reference signal and the IF signal for producing an error signal. Finally, a summing means is coupled to a modulation waveform generator means and the error signal for producing a modulated tuning signal which is input to the VCO to frequency modulate the VCO.
Abstract:
Supplying pulsed current to a load involves repeatedly driving an electrical load between successive active and idle states via a regulator that includes a switched mode power supply. The regulator receives input current from a direct current power source and provides output current to at least an energy storage device in the idle states of the electrical load. The energy storage device is coupled to the load and the regulator. Output current is provided from both the regulator and the energy storage device to the electrical load in the active states of the electrical load. A storage capacity of the energy storage device is selected so that a duty cycle of the input current is greater than a duty cycle of the output current.
Abstract:
The present disclosure relates to multiple embodiments of a signage having radio-frequency responsive features, methods of making and using the signage, and the performance characteristics of the signage. These embodiments include a cutout, aperture, or opening in an electrically conductive sign into which or adjacent to which is placed an RFID tag or chip.
Abstract:
The disclosure generally relates to optical devices, such as interactive displays, and in particular to interactive projection displays having passive input devices. The present disclosure also provides a passive interactive input device having the ability to overcome problematic ambient interference signals in an interactive display, such as an interactive projection display.
Abstract:
Color sequential imaging involves illuminating, for each of two or more time-separated color fields, two or more light sources. Each of the two or more light sources emits at different wavelengths, and at least one of the first or second light sources is activated at different, non-zero current amplitudes during each of the first and second color fields. The color fields are projected via a spatial light modulator in synchronization with the activation of the at least one of the first or second light sources.
Abstract:
This disclosure describes RFID tags designed to provide improved impedance matching capabilities. An RFID tag may include a radiating component and a tuning component located on different layers of the RFID tag. The radiating component and tuning component are located proximate to one another to provide a proximate coupling (e.g., an inductive and/or capacitive coupling). In one embodiment, at least a portion of the radiating component of a first layer overlaps at least a portion of the tuning component of a second layer, resulting in a proximate coupling. The tuning component may be used for tuning the antenna, e.g., matching an impedance of the radiating element and an IC chip electrically connected to the tuning component. Because the radiating element does not have to be designed to match impedances, the radiating element may be designed to provide better gain, polarization purity, larger radar cross section or other antenna parameters.
Abstract:
A passport reader for processing a passport having an RFID element associated therewith. A exemplary embodiment of the invention provides a passport reader for processing a passport having an RFID element associated therewith including an RFID interrogation source for interrogating and obtaining information from the RFID element associated with a passport; and an antenna to transmit signals between an RFID element and the RFID interrogation source.
Abstract:
A Radio-Frequency Identification (RFID) system verifies proper placement and functionality of RFID tags with respect to particular end-use RFID systems at the time the RFID tag is applied to an item but before the item is deployed. A device for verifying a location and functionality of an RFID tag on an item includes an item holder, a power coupling mechanism attached to the item holder, and an RFID reader electrically connected to the power coupling mechanism. The power coupling mechanism creates a near field for transmission of read or write commands from the RFID reader to an RFID tag on an item placed on the item holder to verify the location and functionality of the RFID tag as applied to the item with respect to a near-field coupling mechanism of a particular end-use RFID system. The device may include additional power coupling mechanisms for testing the functionality of the tag.
Abstract:
Methods of monitoring items and/or materials from a manufacturing process. One embodiment of the invention provides a method of monitoring items and/or materials from a manufacturing process using a plurality of RFID tagged containers, and a plurality of stations associated with different portions of the manufacturing process, where each station includes an RFID reader.
Abstract:
Techniques for detecting radio-frequency identification (RFID) tags are disclosed. For example, an exit control system is described that detects unauthorized removal of articles from a protected facility. A series of antennas are setup to produce interrogation corridors located near the exit of the protected area. RFID tags are attached to the articles to be protected. Each tag includes information that uniquely identifies the article to which it is affixed and status information as to whether the articles removal from the facility is authorized. The RF reader outputs RF signals through the antennas to create electromagnetic fields within the interrogation corridors. The reader outputs RF power from a single port to the multiple antennas via a splitter/combiner. In this way, a single RF reader with only one transmitter/receiver port simultaneously interrogates multiple antennas. A variety of techniques are described by which the reader can detect the removal of an unauthorized article.