Apparatus and method for reducing errors in data caused by noise

• US 5,210,518 A
• Filed: 05/10/1991
• Issued: 05/11/1993
• Est. Priority Date: 05/10/1991
• Status: Expired due to Term

• Current Assignee: Echelon Corporation (Renesas Electronics Corporation)
• Original Assignee: Echelon Corporation (Renesas Electronics Corporation)
• Inventors: Graham, Martin H., Lee, Chin-Chen, Sutterlin, Philip H., Johnson, Howard W., Hurlbut, Amy O.
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Lefkowitz, Edward
• Application Number:
  US07/698,600
• Time in Patent Office: 732 Days
• Field of Search: 340/310 R, 340/310 A, 340/310 CP, 455/223, 455/222, 375/104
• US Class Current: 375/351
• CPC Class Codes: H03G 3/345 Muting during a short period of time when noise pulses are detected, i.e. blanking H03G3/348 takes precedence
• 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 2203/5495 having measurements and testing channel
• CPC Class Codes: H04B 3/542 the information being in digital form

Abstract

In a power line communications apparatus an improvement for blanking or snubbing impulse noise. The impulse noise is detected and used to snub the detected signal. The duration of the snubbing pulses is controlled to assure complete blanking of noise including the trailing noise signals following a main noise pulse which may not otherwise be detectable. Also, the number of snubbing pulses which can occur are limited to prevent too much energy from being snubbed during any given baud period.

Claims

1. In an apparatus for receiving a signal representing digital data, said signal being transmitted over a power line to said apparatus, an improvement comprising:

detection means for detecting noise pulses on said power lines said detecting means including frequency dependent means for detecting noise pulses occurring at and above a first frequency and for preventing said noise pulses at and above said first frequency from blocking detection of noise pulses at frequencies below said first frequency; and

,

snubbing means for suppressing said signal representing digital data under control of said detection means, said detection means being coupled to said snubbing means, said snubbing means being controlled by said noise pulses below said first frequency.

2. The apparatus defined in claim 1 wherein said detecting means includes a filter the frequency characteristics of which define a notch at said first frequency.