Power supply line communication modem and power supply line communication system

• US 20060140260A1
• Filed: 03/02/2004
• Published: 06/29/2006
• Est. Priority Date: 03/03/2003
• Status: Abandoned Application

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: Saitoh, Yoshihiro, Wasaki, Masaru, Wasaki, Hitomi
• Application Number:
  US10/545,681
• Publication Number:
  US 20060140260A1
• Time in Patent Office: Days
• US Class Current: 375/219
• CPC Class Codes: H04B 2203/5425 improving S/N by matching impedance, noise reduction, gain control
• CPC Class Codes: H04B 2203/5483 using coupling circuits
• CPC Class Codes: H04B 2203/5491 using filtering and bypassing
• CPC Class Codes: H04B 3/56 Circuits for coupling, blocking, or by-passing of signals

Abstract

A modem for power-line communications (20A) comprises input/output terminals (71a and 71b) and input/output terminals (72a to 72d). The input/output terminals (71a and 71b) are connected to a power line and perform input and output of power-line communications signals. The input/output terminals (72a to 72d) perform input and output of data signals from and to a communications apparatus through a cable. The modem (20A) further comprises: a modem main body (73); a common mode filter (80) provided between the modem main body (73) and the input/output terminals (71a and 71b); and a common mode filter (90) provided between the modem main body (73) and the input/output terminals (72a to 72d).

Claims

1. A modem for power-line communications provided between a power line and a communications apparatus performing communications through the use of the power line, the modem comprising:

a first input/output connected to the power line and performing input and output of power-line communications signals from and to the power line;

a second input/output connected to the communications apparatus and performing input and output of data signals from and to the communications apparatus;

a modem main body that generates a power-line communications signal by modulating carrier waves based on a data signal received at the second input/output and outputs the power-line communications signal to the first input/output, and that demodulates a data signal from a power-line communications signal received at the first input/output and outputs the data signal demodulated to the second input/output; and

common mode filters one of which is provided between the modem main body and the first input/output and the other of which is provided between the modem main body and the second input/output.

2. The modem according to claim 1, wherein an absolute value of impedance of each of the common mode filters at a frequency of 2.0 MHz is 160 ohms or greater.

3. A power-line communications system comprising:

a power line;

a communications apparatus performing communications through the use of the power line; and

a modem for power-line communications provided between the communications apparatus and the power line, the modem incorporating;

a first input/output connected to the power line and performing input and output of power-line communications signals from and to the power line;

a second input/output connected to the communications apparatus and performing input and output of data signals from and to the communications apparatus;

a modem main body that generates a power-line communications signal by modulating carrier waves based on a data signal received at the second input/output and outputs the power line communications signal to the first input/output, and that demodulates a data signal from a power-line communications signal received at the first input/output and outputs the data signal demodulated to the second input/output; and

common mode filters one of which is provided between the modem main body and the first input/output and the other of which is provided between the modem main body and the second input/output.