Power line communication apparatus

• US 4,815,106 A
• Filed: 04/16/1986
• Issued: 03/21/1989
• Est. Priority Date: 04/16/1986
• Status: Expired due to Term

• Current Assignee: Adaptive Networks, Inc.
• Original Assignee: Adaptive Networks, Inc.
• Inventors: Propp, Michael B., Propp, David L.
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Huseman, Marianne
• Application Number:
  US06/852,788
• Time in Patent Office: 1,070 Days
• Field of Search: 375/34, 375/36, 375/58, 375/60, 375/96, 375/103, 375/107, 375/118, 375/106, 375/11, 375/12, 375/14, 375/100, 371/67, 455/43, 455/116, 455/126, 455/340, 340/310 R, 340/310 A, 340/146.2, 333/176, 333/175
• US Class Current: 375/257
• CPC Class Codes: H04B 2203/5408 using protocols
• CPC Class Codes: H04B 2203/5416 by adding signals to the wave form of the power source
• CPC Class Codes: H04B 2203/5425 improving S/N by matching impedance, noise reduction, gain control
• CPC Class Codes: H04B 2203/5445 Local network
• CPC Class Codes: H04B 2203/5483 using coupling circuits
• CPC Class Codes: H04B 2203/5491 using filtering and bypassing
• CPC Class Codes: H04B 3/542 the information being in digital form

Abstract

A power line communication system specially designed for use in local area network (LAN) configurations has receiver and transmitter sections for fast, highly reliable data communication. The receiver includes controlled adaptive second order filters for ensuring data reception in virtually any signal environment having noise and distortion characteristics, especially alternating current (AC) power lines. A wideband phase shift-keyed (PSK) carrier is impressed on the transmission medium, the carrier having power spread approximately uniformly across a useful frequency bandwidth. A transmitter section is arranged for adaptive feedback control of the transmitted signal power, so as to prevent possible damage to the transmitter when the transmission medium impedance is low. A logic control circuit provides a correlation count of a received signal in comparison with a known reference signal in order to effectively achieve phase synchronization between the receiver and transmitter.

Claims

1. A data communication system for communicating a data signal between a first location and a second location over a line having at least a first conductor and a second conductor, the system comprising, at each location:

means for deriving from said line a received wideband signal having power distributed substantially uniformly over a predetermined frequency bandwidth;

means responsive to a first control signal for adaptively filtering said received wideband signal to reduce distortion and noise components of said received signal so that said received signal is thereby substantially equalized;

means for converting said substantially equalized received signal into a periodic serial output stream of binary bits;

means for comparing each of a number of successively received groups of bits in said stream of binary bits to a reference signal at a number of different relative phases;

means responsive to said comparing means for generating a number of count values representing degrees of correlation between each of said groups of bits and said reference signal;

means for identifying a series of groups of bits whose count values match a predetermined pattern of count values; and

means for generating said first control signal in response to an absence of a matching series of count values for a predetermined period of time.

2. The data communication system of claim 1, further comprising:

means for converting a periodic serial input stream of binary bits into a transmit wideband signal having power distributed substantially uniformly over a predetermined frequency bandwidth;

means for applying said transmit wideband signal having a first power level to said line;

means for sensing an impedance of said line;

means responsive to said sensing means for adjusting said first power level to a second power level to protect said applying means from damage.

3. The data communication system of claim 2, wherein said adjusting means adjusts said signal applying means rapidly upon beginning transmission of said transmit wideband signal, and more slowly as transmission is continued.