Abstract: Example apparatus, systems and methods use a receiver of a first device to receive from a second device, radio frequency (RF) signals. Embodiments use a processor of the first device to determine, based on the RF signals, a set of angle-estimation values of an angle between a plurality of antenna elements of one of the first device and the second device and an antenna element of the other of the first device and the second device, and a set of confidence measurements. Each of the set of confidence measurements indicates a confidence of an angle-estimation value of the set of angle-estimation values.

Abstract: Systems, methods, and apparatus use a processor of a first device to wirelessly communicate with a second device using a first antenna. The processor selects the first antenna from a plurality of antennas based on comparing first antenna data associated with the first antenna with second antenna data associated with a second antenna.

Abstract: The invention discloses a method for experimentally determining the conductivity of an unpropped fracture in hydraulic fracturing of a shale reservoir, comprising: select an outcrop sample with a natural fracture in the shale reservoir, and cut the outcrop sample with along the extension direction of the natural fracture into no less than eight square rock slabs; use a laser scanner to obtain the rough topography data of the fracture surface of each square rock slab and calculate the area tortuosity; pick out the rock samples; model the rough surface of the selected rock samples; import the treated surface model into the engraving machine, and select the downhole core or outcrop rocks in the same horizon for repeated production; calculate the shear slippage at different positions of unpropped fracture according to the data of the shale reservoir; finally test the conductivity of the shale rock samples after shear slip.

Abstract: Example apparatus, systems and methods use a receiver of a first device to receive from a second device, radio frequency (RF) signals. Embodiments use a processor of the first device to determine, based on the RF signals, a set of angle-estimation values of an angle between a plurality of antenna elements of one of the first device and the second device and an antenna element of the other of the first device and the second device, and a set of confidence measurements. Each of the set of confidence measurements indicates a confidence of an angle-estimation value of the set of angle-estimation values.

Abstract: The present invention discloses a method for experimentally determining the conductivity distribution of an acid-fractured fracture a carbonate rock oil and gas reservoir, including the following steps: by an acid fracturing simulator FracproPT, simulating and acquiring distribution data of fracture width, fracture height, temperature and acid liquor mass concentration in a hydraulic fracture length direction; selecting fracture width, fracture height and temperature data of total 10 feature points with the acid liquor mass concentrations being from 100% to 10% of the initial mass concentration; converting site acid injection displacement into laboratory acid injection displacement; preparing experimental acid liquor according to the acid liquor mass concentration data of the 10 feature points; and simulating the acid etching process, and experimentally testing the conductivity under the condition of reservoir closed pressure, and drawing a distribution diagram of the acid-etched fracture conductivity in the

Abstract: The invention discloses a method for experimentally determining the conductivity of unpropped fracture in hydraulic fracturing of shale reservoir, comprising the following steps: select an outcrop sample with natural fractures in a shale reservoir section, and cut the outcrop sample with natural fractures along the extension direction of the natural fracture into no less than 8 square rock slabs; use a laser scanner to obtain the rough topography data of the fracture surface of each square rock slab and calculate the area tortuosity; pick out the rock samples; model the rough surface of the selected rock samples; import the treated surface model into the engraving machine, and select the downhole core or outcrop rocks in the same horizon for repeated production; calculate the shear slippage at different positions of unpropped fracture according to the data of shale reservoir; finally test the conductivity of the shale rock samples after shear slip.

Abstract: Systems, methods, and devices enable the implementation of antenna diversity techniques. Devices include a first wireless communications device that includes a plurality of antennas, and a transceiver coupled to the plurality of antennas and configured to send and receive data in accordance with a wireless transmission protocol, while the peer wireless communication device may have a single antenna or multiple antennas. Devices also include a processor configured to, in a first mode, calculate an angle of arrival (AoA) with the plurality of antennas or an angle of departure (AoD) associated with single antenna, and, in a second mode, send data to and receive data from a second wireless communications device via at least a first antenna of the plurality of antennas, where the first antenna is selected by the processor based on one of a first plurality of signal measurements between the first and second wireless communications devices.

Abstract: A device to sense degree of twist in a screwdriver and the magnitude of force applied includes a contacting portion, a deformation portion, a sensing portion, and a processor. The contacting portion receives a grip and twist pressure through the deformation portion which is tiltedly fixed to the contacting portion. The deformation portion carries the sensing portion and elastically deforms under the force and/or the torsion. The sensing portion detects a deformation of the deformation portion and generates a corresponding electrical signal. The processor receives the signal and determines the values of the twist caused and the force applied.

Abstract: A speed reducer includes an input shaft, an output shaft, and a gear assembly coupled to the input shaft. The gear assembly includes a housing, an external gear, and at least two internal gears. The external gear is located within the housing and inscribes the at least two internal gears. One side of the at least two internal gears is rotatably coupled to the input shaft, and another side of the at least two internal gears is coupled to a connecting column of the output shaft. The at least two internal gears are offset on the input shaft, and the input shaft drives the at least two internal gears to maintain engagement with the external gear. The connecting column maintains transmission of the output shaft and the at least two internal gears.

Abstract: A method includes using a receiver of a first device, receiving from a second device, radio frequency (RF) signals. The method also includes using a processor of the first device, determining and storing, based on the RF signals, a set of angle-estimation values of an angle between a plurality of antenna elements of one of the first device and the second device and an antenna element of the other of the first device and the second device, a set of confidence measurements, and at least one of an Area-of Arrival (ARoA) value and an Area-of Departure (ARoD) value. Each of the set of confidence measurements indicates a confidence of an angle-estimation value of the set of angle-estimation values.

Abstract: A device to sense degree of twist in a screwdriver and the magnitude of force applied includes a contacting portion, a deformation portion, a sensing portion, and a processor. The contacting portion receives a grip and twist pressure through the deformation portion which is tiltedly fixed to the contacting portion. The deformation portion carries the sensing portion and elastically deforms under the force and/or the torsion. The sensing portion detects a deformation of the deformation portion and generates a corresponding electrical signal. The processor receives the signal and determines the values of the twist caused and the force applied.

Abstract: Systems, methods, and devices enable the implementation of antenna diversity techniques. Devices include a first wireless communications device that includes a plurality of antennas, and a transceiver coupled to the plurality of antennas and configured to send and receive data in accordance with a wireless transmission protocol, while the peer wireless communication device may have a single antenna or multiple antennas. Devices also include a processor configured to, in a first mode, calculate an angle of arrival (AoA) with the plurality of antennas or an angle of departure (AoD) associated with single antenna, and, in a second mode, send data to and receive data from a second wireless communications device via at least a first antenna of the plurality of antennas, where the first antenna is selected by the processor based on one of a first plurality of signal measurements between the first and second wireless communications devices.

Abstract: A control method for communicating with an external device includes the steps of: when the external device is coupled to a connector, receiving a device existence voltage from the external device; generating a first control signal and a second control signal according to the device existence voltage; coupling a first voltage source or a second voltage source to the connector according to the first control signal, such that a first voltage of the first voltage source or a second voltage of the second voltage source is used as a supply voltage of the external device; and coupling a third voltage source or a fourth voltage source to an output node according to the second control signal, such that a third voltage of the third voltage source or a fourth voltage of the fourth voltage source is used as a tunable output voltage at the output node.

Abstract: A speed reducer includes an input shaft, an output shaft, and a gear assembly coupled to the input shaft. The gear assembly includes a housing, an external gear, and at least two internal gears. The external gear is located within the housing and inscribes the at least two internal gears. One side of the at least two internal gears is rotatably coupled to the input shaft, and another side of the at least two internal gears is coupled to a connecting column of the output shaft. The at least two internal gears are offset on the input shaft, and the input shaft drives the at least two internal gears to maintain engagement with the external gear. The connecting column maintains transmission of the output shaft and the at least two internal gears.

Abstract: A control method for communicating with an external device includes the steps of: when the external device is coupled to a connector, receiving a device existence voltage from the external device; generating a first control signal and a second control signal according to the device existence voltage; coupling a first voltage source or a second voltage source to the connector according to the first control signal, such that a first voltage of the first voltage source or a second voltage of the second voltage source is used as a supply voltage of the external device; and coupling a third voltage source or a fourth voltage source to an output node according to the second control signal, such that a third voltage of the third voltage source or a fourth voltage of the fourth voltage source is used as a tunable output voltage at the output node.

Abstract: Systems, methods, and devices enable the implementation of antenna diversity techniques. Devices include a first wireless communications device that includes a plurality of antennas, and a transceiver coupled to the plurality of antennas and configured to send and receive data in accordance with a wireless transmission protocol, while the peer wireless communication device may have a single antenna or multiple antennas. Devices also include a processor configured to, in a first mode, calculate an angle of arrival (AoA) with the plurality of antennas or an angle of departure (AoD) associated with single antenna, and, in a second mode, send data to and receive data from a second wireless communications device via at least a first antenna of the plurality of antennas, where the first antenna is selected by the processor based on one of a first plurality of signal measurements between the first and second wireless communications devices.

Abstract: Calibrating a Gaussian frequency-shift keying modulation index includes generating a training sequence of bits, shaping a pulse from the training sequence according to an initial modulation index, and converting the shaped signal to a transmission signal. The transmission signal is then either looped through a radio frequency core or processed by frequency deviation estimation hardware to determine a frequency deviation. The frequency deviation is converted to a new modulation index, and potentially a ratio between a target modulation index and a measured modulation index as a scaling factor. The process is then iteratively repeated until a threshold frequency deviation is achieved.

Abstract: An electronic device for communicating with an external device includes a connector, a controller, a first switch element, a second switch element, a first voltage source, a second voltage source, a third voltage source, and a fourth voltage source. When the external device is coupled to the connector, the connector receives a device existence voltage from the external device. The controller generates a first control signal and a second control signal according to the device existence voltage. The first switch element couples the first voltage source or the second voltage source to the connector according to the first control signal. The second switch element couples the third voltage source or the fourth voltage source to an output node according to the second control signal.

Abstract: An electronic device for communicating with an external device includes a connector, a controller, a first switch element, a second switch element, a first voltage source, a second voltage source, a third voltage source, and a fourth voltage source. When the external device is coupled to the connector, the connector receives a device existence voltage from the external device. The controller generates a first control signal and a second control signal according to the device existence voltage. The first switch element couples the first voltage source or the second voltage source to the connector according to the first control signal. The second switch element couples the third voltage source or the fourth voltage source to an output node according to the second control signal.

Abstract: A communication system and method are disclosed for parallel processing of received signals to improve sensitivity of the system. Generally, the method includes demodulating a modulated signal in a first demodulator circuit and a second demodulator circuit in parallel. The first and second demodulated signals are then de-whitened, and a cyclic redundancy code (CRC) check performed on each. If the de-whitened first demodulated signal passes the CRC check a first packet included in the signal is sent to a central processing unit (CPU) for further processing. If the de-whitened second demodulated signal passes the CRC check, and the de-whitened first demodulated signal fails, a second packet included in the de-whitened second demodulated signal is transmitted to the CPU for further processing. In one embodiment, one of demodulator circuits is a GFSK demodulator operated in the phase domain and configured to use maximum likelihood sequence estimation. Other embodiments are also described.