Abstract: Intelligent safety disconnect switching methods and arrangements for PhotoVoltaic (PV) panels are disclosed. A switching device that is connected between a PV panel and a PV panel string detects a low current condition or an arc fault condition in the PV panel string. The switching device is automatically controlled to disconnect the PV panel from the PV panel string responsive to detection of the low current condition or the arc fault condition. Switching device control could also be responsive to a disconnect command. For example, such a command could be generated by a grid sensor responsive to determining that an inverter, to which the PV panel string is connected, is not connected to an electrical grid.

Abstract: The disclosure may provide for a communication method and system. A transmitter of the communication system may include an interleaver and a first encoder for determining parity bits. The transmitter also may include a multiplexer for joining the parity bits with the data. A second encoder may be positioned after the multiplexer for implementing an error correcting code. A receiver of the communication system may include a decoder followed by an interleaver. When errors are detected in received data at the decoder, one or more processors of the receiver may be configured to correct portions of the received data and combine the corrected portions with the received data.

Abstract: Aspects of the disclosure provide techniques for automatic repeat request (ARQ) in a free-space optical communication (FSOC) architecture. These techniques, including block-selective ARQ, adaptive retransmission delay, and random seed scrambling, can be used individually or in combination to combat problems involving frame loss or corruption. These techniques enable the system to rapidly recover by streamlining the retransmission process. For instance, block-selective ARQ acknowledges variable length blocks of frames in the return stream from the receiver to the transmitter. Adaptive retransmission delay allows the retransmission delay to grow in the absence of feedback by the receiver, up to some defined limit. And with random seed sampling, a scrambling sequence is incorporated to aid with frame syncing, which avoids the need for a line code. These aspects of the technology provide a robust communication process, and also reduce overhead costs associated with unnecessary retransmissions.

Abstract: Aspects of the disclosure provide techniques for automatic repeat request (ARQ) in a free-space optical communication (FSOC) architecture. These techniques, including block-selective ARQ, adaptive retransmission delay, and random seed scrambling, can be used individually or in combination to combat problems involving frame loss or corruption. These techniques enable the system to rapidly recover by streamlining the retransmission process. For instance, block-selective ARQ acknowledges variable length blocks of frames in the return stream from the receiver to the transmitter. Adaptive retransmission delay allows the retransmission delay to grow in the absence of feedback by the receiver, up to some defined limit. And with random seed sampling, a scrambling sequence is incorporated to aid with frame syncing, which avoids the need for a line code. These aspects of the technology provide a robust communication process, and also reduce overhead costs associated with unnecessary retransmissions.

Abstract: Aspects of the disclosure provide techniques for automatic repeat request (ARQ) in a free-space optical communication (FSOC) architecture. These techniques, including block-selective ARQ, adaptive retransmission delay, and random seed scrambling, can be used individually or in combination to combat problems involving frame loss or corruption. These techniques enable the system to rapidly recover by streamlining the retransmission process. For instance, block-selective ARQ acknowledges variable length blocks of frames in the return stream from the receiver to the transmitter. Adaptive retransmission delay allows the retransmission delay to grow in the absence of feedback by the receiver, up to some defined limit. And with random seed sampling, a scrambling sequence is incorporated to aid with frame syncing, which avoids the need for a line code. These aspects of the technology provide a robust communication process, and also reduce overhead costs associated with unnecessary retransmissions.

Abstract: The disclosure may provide for a communication method and system. A transmitter of the communication system may include an interleaver and a first encoder for determining parity bits. The transmitter also may include a multiplexer for joining the parity bits with the data. A second encoder may be positioned after the multiplexer for implementing an error correcting code. A receiver of the communication system may include a decoder followed by an interleaver. When errors are detected in received data at the decoder, one or more processors of the receiver may be configured to correct portions of the received data and combine the corrected portions with the received data.

Abstract: The disclosure may provide for a communication method and system. A transmitter of the communication system may include an interleaver and a first encoder for determining parity bits. The transmitter also may include a multiplexer for joining the parity bits with the data. A second encoder may be positioned after the multiplexer for implementing an error correcting code. A receiver of the communication system may include a decoder followed by an interleaver. When errors are detected in received data at the decoder, one or more processors of the receiver may be configured to correct portions of the received data and combine the corrected portions with the received data.

Abstract: The technology relates to the design and placement of beacon transmission optics for free space optical communications (“FSOC”). One aspect of the disclosure provides an FSOC device with a beam steering mechanism, a beam column with a beam expander, an optical bus, and beacon transmission optics. The beacon transmission optics includes a prism that directs outgoing beacon beams into the beam column, and toward the beam steering mechanism. In one embodiment, the outgoing beacon beams do not need to travel through the beam expander of the beam column. As a result, backscatter is minimized and incoming or outgoing beams can be controlled with a single beam-steering mechanism.

Abstract: Aspects of the disclosure provide techniques for automatic repeat request (ARQ) in a free-space optical communication (FSOC) architecture. These techniques, including block-selective ARQ, adaptive retransmission delay, and random seed scrambling, can be used individually or in combination to combat problems involving frame loss or corruption. These techniques enable the system to rapidly recover by streamlining the retransmission process. For instance, block-selective ARQ acknowledges variable length blocks of frames in the return stream from the receiver to the transmitter. Adaptive retransmission delay allows the retransmission delay to grow in the absence of feedback by the receiver, up to some defined limit. And with random seed sampling, a scrambling sequence is incorporated to aid with frame syncing, which avoids the need for a line code. These aspects of the technology provide a robust communication process, and also reduce overhead costs associated with unnecessary retransmissions.

Abstract: The disclosure may provide for a communication method and system. A transmitter of the communication system may include an interleaver and a first encoder for determining parity bits. The transmitter also may include a multiplexer for joining the parity bits with the data. A second encoder may be positioned after the multiplexer for implementing an error correcting code. A receiver of the communication system may include a decoder followed by an interleaver. When errors are detected in received data at the decoder, one or more processors of the receiver may be configured to correct portions of the received data and combine the corrected portions with the received data.

Abstract: Aspects of the disclosure provide techniques for automatic repeat request (ARQ) in a free-space optical communication (FSOC) architecture. These techniques, including block-selective ARQ, adaptive retransmission delay, and random seed scrambling, can be used individually or in combination to combat problems involving frame loss or corruption. These techniques enable the system to rapidly recover by streamlining the retransmission process. For instance, block-selective ARQ acknowledges variable length blocks of frames in the return stream from the receiver to the transmitter. Adaptive retransmission delay allows the retransmission delay to grow in the absence of feedback by the receiver, up to some defined limit. And with random seed sampling, a scrambling sequence is incorporated to aid with frame syncing, which avoids the need for a line code. These aspects of the technology provide a robust communication process, and also reduce overhead costs associated with unnecessary retransmissions.

Abstract: The disclosure provides for a system that includes a plurality of stations equipped for free-space optical communications (FSOC) in a network and a central control system. At least one station in the plurality of stations includes a wavelength selectable switch, an OEO module, and one or more first processors. The one or more first processors are configured to control the wavelength selectable switch, process an electrical signal that is extracted using the OEO module, and communicate with the central control system. The central control system includes one or more second processors that are configured to receive data regarding FSOC communication conditions at the plurality of stations, determine a path between stations through the network based on the received data, and transmit instructions to the plurality of stations.

Abstract: A wearable computing device such as a head-mounted display (HMD) may be equipped with a magnetometer for detecting presence and motion of a hand-wearable magnet (HWM). The HMD may analyze magnetic field measurements of the magnetometer to determine when the HWM moves within a threshold distance of the magnetometer, and may thereafter determine one or more patterns of motion of the HWM based the magnetic field measurements. The HMD may operate in a background detection state in order to determine a background magnetic field strength and to monitor for magnetic disturbances from the HWM. Upon occurrence of a trigger event corresponding to magnetic disturbance above a threshold level, the HMD may transition to operating in a gesture detection state in which it analyzes magnetometer measurements for correspondence with known gestures. Upon recognizing a known gesture, the HMD may carry out one or more actions based on the recognized known gesture.

Abstract: Aspects of the disclosure provide for a method for determining a position of a beacon. A plurality of frames comprising pixel values is collected. Each frame is an image of a location. A static background of the location is determined by averaging the pixel values of the plurality of frames, pixel difference values are determined for each frame by subtracting the determined static background from the pixel values of each frame. Using the pixel difference values for each frame in the plurality of frames, a first subset of frames and a second subset of frames are identified. An average pixel difference is then determined by averaging the pixel difference values of the first subset of frames and an inverse of the pixel difference values of the second subset of frames. Using the average pixel difference, the position of a beacon at the location is determined.

Abstract: Aspects of the disclosure provide for a method of forming a communication link between two communication devices using a primary search pattern and a secondary search pattern. A misalignment between a first optical system of a first communication device and a second optical system of a second communication device is detected. The first optical system is rotated according to the primary search pattern, and the second optical system according to the secondary search pattern. At the second communication device, a set of frames is captured. Then, it is determined whether a beacon beam transmitted from the first communication device is detected in the one or more of the captured frames. When it is determined that the beacon beam is detected, the communication link is formed between the first communication device and the second communication device.

Abstract: Aspects of the disclosure provide techniques for automatic repeat request (ARQ) in a free-space optical communication (FSOC) architecture. These techniques, including block-selective ARQ, adaptive retransmission delay, and random seed scrambling, can be used individually or in combination to combat problems involving frame loss or corruption. These techniques enable the system to rapidly recover by streamlining the retransmission process. For instance, block-selective ARQ acknowledges variable length blocks of frames in the return stream from the receiver to the transmitter. Adaptive retransmission delay allows the retransmission delay to grow in the absence of feedback by the receiver, up to some defined limit. And with random seed sampling, a scrambling sequence is incorporated to aid with frame syncing, which avoids the need for a line code. These aspects of the technology provide a robust communication process, and also reduce overhead costs associated with unnecessary retransmissions.

Abstract: A wearable computing device such as a head-mounted display (HMD) may be equipped with a magnetometer for detecting presence and motion of a hand-wearable magnet (HWM). The HMD may analyze magnetic field measurements of the magnetometer to determine when the HWM moves within a threshold distance of the magnetometer, and may thereafter determine one or more patterns of motion of the HWM based the magnetic field measurements. The HMD may operate in a background detection state in order to determine a background magnetic field strength and to monitor for magnetic disturbances from the HWM. Upon occurrence of a trigger event corresponding to magnetic disturbance above a threshold level, the HMD may transition to operating in a gesture detection state in which it analyzes magnetometer measurements for correspondence with known gestures. Upon recognizing a known gesture, the HMD may carry out one or more actions based on the recognized known gesture.

Abstract: Intelligent safety disconnect switching methods and arrangements for PhotoVoltaic (PV) panels are disclosed. A switching device that is connected between a PV panel and a PV panel string detects a low current condition or an arc fault condition in the PV panel string. The switching device is automatically controlled to disconnect the PV panel from the PV panel string responsive to detection of the low current condition or the arc fault condition. Switching device control could also be responsive to a disconnect command. For example, such a command could be generated by a grid sensor responsive to determining that an inverter, to which the PV panel string is connected, is not connected to an electrical grid.

Abstract: Intelligent safety disconnect switching methods and arrangements for PhotoVoltaic (PV) panels are disclosed. A determination is made as to whether a reconnect condition, for reconnecting a PV panel to a power system from which the PV panel is disconnected, is satisfied. The PV panel is automatically reconnected to the power system responsive to determining that the reconnect condition is satisfied. A determination is then made as to whether a power system operating condition is satisfied on reconnection of the PV panel, and the PV panel is automatically disconnected from the power system responsive to determining that the power system operating condition is not satisfied on reconnection of the PV panel.

Abstract: In a switching mode power converter coupled between first and second terminal pairs, a first circuit path includes a first inductance and a first switch. A tapped transformer has a first winding coupled across the first inductance and a tapped second winding with a tapped winding portion. A second circuit path includes a capacitance coupled to a second inductance, and the second circuit path is coupled to the first inductance through the tapped winding portion in a third circuit path and through the second winding in a fourth circuit path. During their respective conduction periods, the first switch couples the first inductance across the first terminal pair, a second switch completes a circuit between the second terminal pair and the second circuit path or the third circuit path, and a third switch completes a circuit that includes another of the second circuit path and the fourth circuit path.