One of a plurality of radio communication apparatuses (100) becomes a master apparatus (100-M), and a rest of them become slave apparatuses (100-S). The master apparatus and each of the slave apparatus includes a plurality of transceivers (31) each composed of a transmitter and a receiver and first ports (55 and 56). The master apparatus further includes a calibration transceiver (51). The first port of the master apparatus is connected to the first port of the slave apparatus via an RF cable. When transmission calibration is performed, each transmitter of the slave apparatus transmits a transmission calibration signal to the calibration transceiver of the master apparatus via the RF cable. When reception calibration is performed, the calibration transceiver of the master apparatus transmits a reception calibration signal to each receiver of the slave apparatus via the RF cable.

System and method for measuring path loss of a conductive radio frequency (RF) signal path used in testing a RF data signal transceiver device under test (DUT) with a RF vector signal transceiver. A path loss measurement may be performed by initially leaving an open connection at the RF signal path end normally connected to the DUT during DUT testing. Sourcing the RF test signal with the RF vector signal transceiver at multiple test frequencies avoids need for additional testing with shorted and loaded connections at the RF signal path end.

A method is provided for calibrating a terminal device connected to a transmission line containing an impairment. The method includes steps of obtaining a sequence of frequency domain samples for a digital signal transmitted to the terminal device, determining a reflection coefficient from the obtained frequency domain sequence and a reflection signal arising from the impairment, converting the sequence of frequency domain samples and the frequency domain reflection signal into the time domain to generate a complex time domain sample sequence having a real I time component and an imaginary Q time component, correcting the time domain sample sequence into a corrected time sequence having a phase value of the Q component corresponding to a phase value of the I component, calculating a correcting spin coefficient from the corrected time sequence, and calibrating the terminal device with the correcting spin coefficient to mitigate a rotation of the reflection coefficient.

A method is provided for calibrating a terminal device connected to a transmission line containing an impairment. The method includes steps of obtaining a sequence of frequency domain samples for a digital signal transmitted to the terminal device, determining a reflection coefficient from the obtained frequency domain sequence and a reflection signal arising from the impairment, converting the sequence of frequency domain samples and the frequency domain reflection signal into the time domain to generate a complex time domain sample sequence having a real I time component and an imaginary Q time component, correcting the time domain sample sequence into a corrected time sequence having a phase value of the Q component corresponding to a phase value of the I component, calculating a correcting spin coefficient from the corrected time sequence, and calibrating the terminal device with the correcting spin coefficient to mitigate a rotation of the reflection coefficient.

A photovoltaic system includes an inverter and a plurality of photovoltaic units connected to the inverter. Each photovoltaic unit includes a controller and one or more photovoltaic modules connected to the controller. The controller in each photovoltaic unit is further configured to obtain a power carrier signal sent by a controller in another photovoltaic unit of the plurality of photovoltaic units, determine an attenuation reference factor of the power carrier signal based on the obtained power carrier signal, and send the attenuation reference factor to the inverter. The inverter is further configured to group the plurality of photovoltaic units based on the attenuation degree of the power carrier signal obtained by each photovoltaic unit. This application can implement automatic grouping of photovoltaic units.

A photovoltaic system includes an inverter and a plurality of photovoltaic units connected to the inverter. Each photovoltaic unit includes a controller and one or more photovoltaic modules connected to the controller. The controller in each photovoltaic unit is further configured to obtain a power carrier signal sent by a controller in another photovoltaic unit of the plurality of photovoltaic units, determine an attenuation reference factor of the power carrier signal based on the obtained power carrier signal, and send the attenuation reference factor to the inverter. The inverter is further configured to group the plurality of photovoltaic units based on the attenuation degree of the power carrier signal obtained by each photovoltaic unit. This application can implement automatic grouping of photovoltaic units.

Certain aspects of the present disclosure provide techniques for determining a cable loss associated with a transmission cable of an apparatus. An example method includes sending, to a radio modem of the apparatus, a request for the radio modem to use a target power when sending one or more signals to the signal compensator device for determining a cable loss associated with a transmission cable communicatively coupling the radio modem with the signal compensator device, receiving, at a signal compensator device of the apparatus, the one or more signals from the radio modem sent using the target power, and determining the cable loss associated with the transmission cable based on the one or more signals.

Certain aspects of the present disclosure provide techniques for determining a cable loss associated with a transmission cable of an apparatus. An example method includes sending, to a radio modem of the apparatus, a request for the radio modem to use a target power when sending one or more signals to the signal compensator device for determining a cable loss associated with a transmission cable communicatively coupling the radio modem with the signal compensator device, receiving, at a signal compensator device of the apparatus, the one or more signals from the radio modem sent using the target power, and determining the cable loss associated with the transmission cable based on the one or more signals.

Embodiments of the present disclosure relate to an apparatus including means configured to perform: obtaining a measured channel frequency response, and a measured noise power spectral density for a line of a wired network susceptible to an impairment; deriving, in case of an indication of an impairment present on the line, from the measured channel frequency response and the measured noise power spectral density, a first theoretical noise representation for the line with the impairment and a second theoretical noise representation for the line without the impairment; and determining information indicative of a location of the impairment in the line, by processing the measured noise power spectral density, the first theoretical noise representation, and the second theoretical noise representation with a neural network.

Embodiments of the present disclosure relate to an apparatus including means configured to perform: obtaining a measured channel frequency response, and a measured noise power spectral density for a line of a wired network susceptible to an impairment; deriving, in case of an indication of an impairment present on the line, from the measured channel frequency response and the measured noise power spectral density, a first theoretical noise representation for the line with the impairment and a second theoretical noise representation for the line without the impairment; and determining information indicative of a location of the impairment in the line, by processing the measured noise power spectral density, the first theoretical noise representation, and the second theoretical noise representation with a neural network.