Secondary surge protection means for equipment connected to transmission lines, for example line-powered amplifiers (10) interconnecting T1 or T1C telephone lines, includes two diode bridges (21; 26) and a pair of surge diverters (30; 31). One diode bridge has its cathode/anode nodes connected one to each conductor (11; 12) of an incoming transmission line. The other diode bridge is connected in like manner to an outgoing transmission line (13; 14). Each surge diverter interconnects the anode/anode node (23) of one bridge and the cathode/cathode node (32) of the other bridge. When a surge on one line causes the voltage across one or other diverter to exceed a predetermined threshold, the diverter conducts, shunting the surge past the amplifier to dissipate in the other line. The two transmission lines may be coupled to the input and output, respectively, of one amplifier, or to the input of one amplifier and the output of a different, oppositely connected amplifier. In both cases, power for the or each amplifier may be derived from the two lines, for example by a Zener diode (35) interconnecting them in known manner. The characteristics of each surge diverter are such that it will respond to fast rise-time lightning pulses yet tolerate long duration power surges, and will be operated by differential mode or common mode surges.

Disclosed is a DC circuit breaker capable of interrupting fault currents flowing in both forward and backward directions. The DC circuit breaker includes: a mechanical switch installed on a DC transmission line and being opened to interrupt a current in the DC transmission line when a fault occurs at one side or remaining side thereof on the DC transmission line; a first bidirectional switching device connected in parallel with the mechanical switch and switching currents flowing in both forward and backward directions; an LC circuit connected in parallel with the mechanical switch and including a capacitor and a reactor connected in series to induce LC resonance; a first unidirectional switching device connected in parallel with the LC circuit and switching a current to induce LC resonance; and a second bidirectional switching device connected in series with the LC circuit and switching currents flowing in both forward and backward directions.

The present invention discloses a parameter obtaining method and apparatus, so as to resolve a problem that manual analysis of a received-signal constellation diagram is not applicable to a higher-order quadrature amplitude modulation QAM scheme, and an analysis result depends on an technical level. In this method, multiple signals are received over a communications link on a network, where each of the received signals is corresponding to a point on a complex plane; decision is performed on each of the received signals, so as to obtain a decision signal; for each of the received signals, an error signal between the received signal and a corresponding decision signal is determined; and a complex-plane distribution feature parameter used to indicate a distribution feature, on the complex plane, of the signals received over the communications link is determined according to all the determined error signals. In this method, maintenancean inaccurate maintenance result in manual analysis of a constellation diagram is avoided, and in addition, there is no modulation order restriction because the complex-plane distribution feature parameter is obtained by using the error signals.

The present invention relates to a modular electronic and/or electric apparatus including a plurality of circuit units (10, 12, 14) connected by an internal communication bus (22). The circuit unit (10, 12, 14) comprises at least two serial resistor elements (RI1, ROI, RI2, R02, RIN, RON) forming a voltage divider. The resistor elements (RI1, RO1, RI2, R02, RIN, RON) of the circuit units (10, 12, 14) are serially connected and form an ID wire. The ID wire is interconnected between a first voltage terminal (VDD) and a second voltage terminal (VSS). The circuit unit (10, 12, 14) comprises at least one analogue-digital converter. A connection point between two resistor elements (RI1, RO1, RI2, R02, RIN, RON) of one circuit unit (10, 12, 14) is connected to an analogue input terminal of the analogue-digital converter. A digital output terminal of the analogue-digital converter is connected to the internal communication bus (22). The modular electronic and/or electric apparatus comprises a master unit (16) connected to the internal communication bus (22). In particular, the present invention relates to a modular domestic appliance including a plurality of circuit units connected by an internal communication bus.

A surge isolating device includes an isolation unit (300) that includes a tubular conductive body (3), an inductor (4), an annular capacitor (51a) and an annular conductive member (61a). The tubular conductive body (3) extends along an axial direction, is electrically connected to a conductive input-end housing (11), has a transmission wire (201) extending therethrough, and is capable of generating mutual inductance with the transmission wire (201). The inductor (4) is capable of generating mutual inductance with the tubular conductive body (3). The annular capacitor (51a) surrounds the tubular conductive body (3) and has a surface (512) electrically connected to a conductive output-end housing (12). The annular conductive member (61a) surrounds fittingly and tightly on the tubular conductive body (3) and contacting another surface (511) of the annular capacitor (51a) so as to be electrically connected to the conductive input-end housing (11).

A system and method for power control in a physical layer device. Energy savings during an active state can be produced through the monitoring of a received signal level by a receiver in a physical layer device. In one embodiment, based on an indication of the received signal level or other communication characteristic of the transmission medium, a control module can adjust the signal level or amplitude and/or adjust the voltage supply.

The present invention relates to an access node (200) with point-to-multi-point transmission capabilities. The access node comprises first transmit/receive circuitry (210m) with digital signal processing logic (DSP) and digital-to-analog/analog-to-digital conversion logic (DAC; ADC), and second transmit/receive circuitry (220n) with transmit/receive amplifiers (LD; LNA) and line adaptation units (LAU) for connection to a transmission line (Ln).

The access node further comprises an analog switch (230) for dynamically connecting one of the first transmit/receive circuitry with one of the second transmit/receive circuitry according to a transmit/receive cross-connect table (XT), and transmit/receive control logic (240) for updating the transmit cross-connect table according to a transmit/receive traffic pattern over the respective transmission lines.

The transmit/receive traffic pattern conforms to a Time-Division Multiple Access TDMA scheme, or is determined according to actual transmit/receive traffic demands.

The transmit/receive control logic is further for individually disabling or enabling the transmit/receive amplifiers concomitantly with the updating of the cross-connect table.

The present invention provides a high reliability information transmission system which can continue transmission at the occurrence of multiple failures.

Providing two key transmission lines, connecting transmission terminals to both of the key transmission lines, transmitting data to both key transmission lines, causing respective transmission terminals to always check reception status, and causing the relaying function to relay data from one transmission line to the other transmission line when the data does not come from one of the transmission lines.