Abstract: Systems and methods for radiolocation using backscatter RFID tags and a special-purpose reader that produces a SFCW RF interrogation signal comprising N carrier frequencies. A backscattered interrogation signal from a backscatter RFID tag is down-converted using at least a portion of the generated SFCW RF interrogation signal. RSP corresponding to the N carrier frequencies are determined. RSS may be determined to improve performance. A distance between the RFID reader and the backscatter RFID tag may be estimated based on at least a summation of differences between RSPs corresponding to adjacent carrier frequencies.

Abstract: In embodiments, an object location system is configured to receive a transmitted tag package from a Radio Frequency (RF) tag associated with an object. The transmitted tag package includes a representation of RF signals received by the RF tag from respective RF signal sources. The object location system is configured to access multiple data models associated with a respective subspace and generated by associating a RF signal sample received by a tag in the associated subspace at a prior time. The object location system is configured to compare the representation of RF signals to each of the plurality of data models. The object location system is configured to select a candidate data model having a highest correlation with the representation of the RF signals from the comparison. The object location system is configured to predict that the object is located in a subspace associated with the candidate data model.

Abstract: Systems and methods for radiolocation using backscatter RFID tags and a special-purpose reader that produces a SFCW RF interrogation signal comprising N carrier frequencies. A backscattered interrogation signal from a backscatter RFID tag is down-converted using at least a portion of the generated SFCW RF interrogation signal. RSP corresponding to the N carrier frequencies are determined. RSS may be determined to improve performance. A distance between the RFID reader and the backscatter RFID tag may be estimated based on at least a summation of differences between RSPs corresponding to adjacent carrier frequencies.

Abstract: An audio player device includes a digital-to-analog converter (DAC), a startup circuit, a multiplexer and an output amplifier. The DAC converts audio data into a first signal and a second signal. The startup circuit gradually increases a level of a startup voltage according to a reference voltage during a predetermined period. The multiplexer outputs the startup voltage as a control voltage during the predetermined period, and switches to output the reference voltage as the control voltage after the predetermined period has elapsed. The output amplifier generates an audio signal according to the control voltage, the first signal and the second signal. The control voltage is used to set a common mode voltage of the output amplifier.

Abstract: Systems and methods are disclosed for radiolocation using backscatter RFID tags and a special-purpose reader that produces a stepped-frequency continuous wave (SFCW) radio frequency (RF) interrogation signal comprising N carrier frequencies. A backscattered interrogation signal from a backscatter RFID tag is down-converted using at least a portion of the generated SFCW RF interrogation signal. Received signal phases (RSP) corresponding to the N carrier frequencies are determined. Received signal strength (RSS) may be determined to improve performance. A distance between the RFID reader and the backscatter RFID tag may be estimated based on at least a summation of differences between RSPs corresponding to adjacent carrier frequencies.

Abstract: Location of objects within an identified subspace defined within a predefined master space. The system includes an RF beacon associated with an object, the RF beacon transmitting signals to one or more of RF tags transmitting to an object location system a tag data package including an identification of the signals received by the RF tags from the RF beacon. The system includes a gateway receiving and extracting, from the transmitted tag data package, the identification of signals. The system further includes the location engine accessing an ML model trained by performing a survey of RF signals received from a plurality of RF signal sources during a prior RF master space survey operation and determining a subspace identifier corresponding to a predicted subspace location for the object by comparing the identification of signals included in the received tag data package to a model plurality of signals accessed from the model.

Abstract: Systems and methods are disclosed for radiolocation using backscatter RFID tags and a special-purpose reader that produces a stepped-frequency continuous wave (SFCW) radio frequency (RF) interrogation signal comprising N carrier frequencies. A backscattered interrogation signal from a backscatter RFID tag is down-converted using at least a portion of the generated SFCW RF interrogation signal. Received signal phases (RSP) corresponding to the N carrier frequencies are determined. Received signal strength (RSS) may be determined to improve performance. A distance between the RFID reader and the backscatter RFID tag may be estimated based on at least a summation of differences between RSPs corresponding to adjacent carrier frequencies.

Abstract: Location of objects associated with radio frequency (RF) tags in a particular subspace or room within a predefined master space. A plurality of multi-channel radio beacons (e.g. Bluetooth Low Energy or BLE) transmit signals into the master space. A survey operation is conducted to detect RF signals, e.g. RSSI values, from the beacons within predefined subspaces within the master space. Data from the survey operation is used to construct one or more machine learning (ML) data models. Each object to be located is provided with a dual mode RF tag that receives beacon signals when placed into a subspace and activates (e.g. by motion or command) to transmit data containing RSSI of beacon signals to an object location system. The system runs the received beacon signals against the ML data models and returns a prediction candidate of a particular subspace corresponding to a likely location of the tag and object.

Abstract: For sewage sludge reduction, an apparatus includes a front-end auxiliary filter plate, a back-end auxiliary filter plate, and a plurality of filter plate modules disposed between the front-end auxiliary filter plate and the back-end auxiliary filter plate. Each filter plate module includes a middle main filter plate, a middle auxiliary filter plate, and a plurality of electromagnetic modules comprising an electromagnetic coil wound around an electromagnetic core. The middle main filter plate and the middle auxiliary filter plate are disposed at opposite sides of the electromagnetic modules. An electric current is applied to the electromagnetic coil, attracting the middle auxiliary filter plates and the main filter plates and applying pressure to the sewage sludge.

Abstract: For sewage sludge reduction, an apparatus includes a front-end auxiliary filter plate, a back-end auxiliary filter plate, and a plurality of filter plate modules disposed between the front-end auxiliary filter plate and the back-end auxiliary filter plate. Each filter plate module includes a middle main filter plate, a middle auxiliary filter plate, and a plurality of electromagnetic modules comprising an electromagnetic coil wound around an electromagnetic core. The middle main filter plate and the middle auxiliary filter plate are disposed at opposite sides of the electromagnetic modules. An electric current is applied to the electromagnetic coil, attracting the middle auxiliary filter plates and the main filter plates and applying pressure to the sewage sludge.

Abstract: A baggage lock device to halt rotation of caster wheels as the handle is retracted, and allow the wheels to move as the handle is pulled out. The device has a receptacle with a handle extendable to be pulled put. A wheel halting mechanism has a traction cord inhibiting wheel rotation by a force pressed against the wheel as operation of an operation mechanism is transmitted via a pulling force transmission mechanism having a pulled wire, a brake pad, a linking member, and means for restoring the position of the operated elements.”.