Abstract: A wireless communication circuit and a transport device for sending rescue message are provided. The wireless communication circuit is arranged in a transport device for sending a rescue message to a cellular network and includes a radio transceiver, a signal amplifier circuit, a plurality of filters, and a first switch. The radio transceiver converts a baseband signal to a radio frequency signal and determines whether the cellular network has been connected. The first switch includes an input end and a plurality of output ends, and is electrically connected between the signal amplifier circuit and the plurality of filters. The first switch connects the input end and one of the plurality of output ends in sequence until the radio transceiver determines the cellular network has been connected. The wireless radio transceiver sends the rescue message through the first switch.

Abstract: An optical fiber connector, a single-fiber bidirectional optical assembly, and an optical fiber transmission system are provided. The optical fiber connector is used in a single-fiber bidirectional optical assembly that includes a first optical module and a light filter. The optical fiber connector includes an optical path changing module, an optical fiber, a ferrule, and a tube. The optical fiber is disposed in the ferrule, the optical path changing module is in physical contact with the ferrule, the optical path changing module and the ferrule are fastened through the tube, and an optical path port is disposed at a location that is on the tube opposite from the first optical module. The optical path changing module is configured to change a transmission path of a first optical signal.

Abstract: A wireless communication circuit and a transport device for sending rescue message are provided. The wireless communication circuit is arranged in a transport device for sending a rescue message to a cellular network and includes a radio transceiver, a signal amplifier circuit, a plurality of filters, and a first switch. The radio transceiver converts a baseband signal to a radio frequency signal and determines whether the cellular network has been connected. The first switch includes an input end and a plurality of output ends, and is electrically connected between the signal amplifier circuit and the plurality of filters. The first switch connects the input end and one of the plurality of output ends in sequence until the radio transceiver determines the cellular network has been connected. The wireless radio transceiver sends the rescue message through the first switch.

Abstract: An optical fiber connector, a single-fiber bidirectional optical assembly, and an optical fiber transmission system are provided. The optical fiber connector is used in a single-fiber bidirectional optical assembly that includes a first optical module and a light filter. The optical fiber connector includes an optical path changing module, an optical fiber, a ferrule, and a tube. The optical fiber is disposed in the ferrule, the optical path changing module is in physical contact with the ferrule, the optical path changing module and the ferrule are fastened through the tube, and an optical path port is disposed at a location that is on the tube opposite from the first optical module. The optical path changing module is configured to change a transmission path of a first optical signal.

Abstract: A method for on-line diagnosing gradually-changing fault of electronic current transformers comprises the following steps collecting output signals of electronic transformers of a whole transformer substation, calculating theoretical instantaneous values of the current at the tail ends of power transmission lines and on secondary sides of transformers at every moment, comparing the theoretical instantaneous values with the corresponding collected values, calculating residual errors of the electronic current transformers at the head and tail ends of each power transmission line and the primary and the secondary sides of each transformer respectively, judging whether gradually-changing fault occurs with the electronic current transformers by comparing the residual errors with preset threshold values, and simultaneously performing Kirchhoff detection by injecting current into a busbar to position a fault transformer.

Abstract: A multi-layer printed circuit board includes a first layer, a second layer, at least one third layer, a conductive via hole, and a capacitor electronically coupled to the conductive via hole. The at least one third layer is sandwiched between the first and second layers. The conductive via hole is defined through the first, second and third layers, and having a parasitic inductance. The capacitor and the parasitic inductance of the conductive via hole cooperatively form a low-pass filter that is configured to filter noise signal induced by conductive via hole due to the parasitic inductance.

Abstract: In at least some embodiments, a multicast communication system includes sender and a plurality of receivers in communication with the sender. The sender is configured to multicast a data packet to the plurality of receivers. The plurality of receivers are configured to acknowledge the data packet received from the sender based on weakest member selection without a sender-side competitive time window.

Abstract: In at least some embodiments, a multicast communication system includes sender and a plurality of receivers in communication with the sender. The sender is configured to multicast a data packet to the plurality of receivers.