Device for determining a common-mode signal in a power line communication network

Abstract

A device for determining a common-mode signal in a power line communication network. The device includes a first line, a second line, and a third line that are connected to a first terminal, to a second terminal, and to a third terminal, respectively. The first, the second, and the third terminal are configured to be connected to a phase line, a neutral line, and a protective ground line of the power line communication network, respectively. The device further includes a common-mode choke configured to couple out the common signal from the first, second, and third line, and the common-mode choke is connected to a termination impedance which is higher than an impedance of the power line communication network.

What is claimed is: 
     
         1 . A Power Line Communication (PLC) device, comprising:
 a phase line coupled to a phase line terminal;   a neutral line coupled to a neutral line terminal;   a protective earth line coupled to a protective earth terminal; and   a first high pass filter connected in line with the protective earth line.   
     
     
         2 . The device according to  claim 1 ,
 wherein the first high pass filter includes a capacitor and is coupled to a first inductive element.   
     
     
         3 . The device according to  claim 2 ,
 wherein the protective earth line is coupled to the first inductive element and a second inductive element.   
     
     
         4 . The device according to  claim 1 , further comprising:
 a second high-pass filter connected in line with the phase line, a first end of the second high-pass filter being coupled to the phase line terminal, and a second end of the second high-pass filter being coupled to a first impedance element; and   a third capacitor connected in line with the neutral line, a first end of the third capacitor being coupled to the neutral terminal, and a second end of the third capacitor being coupled to a second impedance element,   wherein the first and second high pass filters include first and second capacitors, respectively.   
     
     
         5 . The device according to  claim 1 ,
 further comprising a first capacitor connected in line with the phase line, a first end of the first capacitor being coupled to a first impedance element.   
     
     
         6 . The device according to  claim 5 ,
 further comprising a second capacitor connected in line with the neutral line, a first end of the second capacitor being coupled to a second impedance element.   
     
     
         7 . The device according to  claim 6 ,
 wherein a second end of the first capacitor is coupled to the phase line terminal,   wherein a second end of the second capacitor is coupled to the neutral line terminal, and   wherein a first end of the first high pass filter is coupled to a first inductive element.   
     
     
         8 . The device according to  claim 7 ,
 wherein the first inductive element is a transformer.   
     
     
         9 . The device according to  claim 6 ,
 wherein the first capacitor and second capacitors are isolation capacitors to isolate the device against direct current signals in the phase and neutral lines, respectively.   
     
     
         10 . The device according to  claim 6 ,
 wherein the first high pass filter is coupled to a third impedance element.   
     
     
         11 . The device according to  claim 1 ,
 wherein the first high pass filter is coupled to an impedance element having a value of 50 Ohms.   
     
     
         12 . The device according to  claim 11 ,
 wherein the impedance element is different from a first inductive element coupled to the first high pass filter.   
     
     
         13 . The device according to  claim 1 ,
 wherein a first end of the first high pass filter is coupled to the protective earth terminal, and   wherein a second end of the first high pass filter is coupled to a first inductive element.   
     
     
         14 . The device according to  claim 1 ,
 wherein said device is a multiple-input and multiple-output (MIMO) Power Line Communication (PLC) modem to receive symmetrical or balanced input communication signals and has a plurality of inputs and a plurality of outputs, and   wherein said modem is one of a plurality of said modems included in a local power line network.   
     
     
         15 . The device according to  claim 14 ,
 wherein a number of inputs to said modem differs from a number of outputs from said modem.