Binary data error correction using hint signal

• US 5,195,098 A
• Filed: 05/10/1991
• Issued: 03/16/1993
• 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: Sutterlin, Philip H., Johnson, Howard W., Hurlbut, Amy O.
• Primary Examiner(s): ATKINSON, CHARLES
• Application Number:
  US07/698,602
• Time in Patent Office: 676 Days
• Field of Search: 371/37.2, 371/37.7, 371/6, 340/310 R
• US Class Current: 714/753
• CPC Class Codes: G06F 11/10 Adding special bits or symbols to the coded information, e.g. parity check, casting out 9's or 11's
• CPC Class Codes: H03M 13/00 Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes error detection or error correction for analogue/digital, digital/analogue or code conversion H03M1/00 – H03M11/00; specially adapted for digital computers G06F11/08; for information storage based on relative movement between record carrier and transducer G11B, e.g. G11B20/18; for static stores G11C
• CPC Class Codes: H03M 13/098 using single parity bit
• CPC Class Codes: H03M 13/151 using error location or error correction polynomials
• CPC Class Codes: H03M 13/19 Single error correction without using particular properties of the cyclic codes, e.g. Hamming codes, extended or generalised Hamming codes
• CPC Class Codes: H03M 13/25 Error detection or forward error correction by signal space coding, i.e. adding redundancy in the signal constellation, e.g. Trellis Coded Modulation [TCM] modulation codes H03M13/31
• CPC Class Codes: H03M 13/251 with block coding
• 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
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/22 using redundant apparatus to increase reliability

Abstract

An error detection and correction method and apparatus is described which permits the correction of double errors using a (15,11) Hamming code and a parity bit. The Hamming code and parity bit allows the detection of double errors. A modulated waveform carrying the binary data is examined for anomalies such as noise pulses. A hint signal is generated based on the anomalies which points to a suspect bit. The state of this bit is changed to correct for double errors.

Claims

1. In an apparatus for handling a signal representing binary data, an improved method for correcting errors in said binary data comprising the steps of:

examining said signal for noise pulses which exceed certain limits;

determining which datum was present in said binary data at the point in said signal where said noise pulse occurred;

verifying the correctness of a predetermined group of data which includes said datum; and

,

changing the state of said datum if said data was found to be incorrect by said verifying step.

2. The method defined by claim 1 wherein said verification comprises a parity check.

3. The method defined by claim 1 wherein said verification comprises a Hamming code check.

4. In an apparatus for handling a signal representing binary data, an improved method for correcting errors in said binary data comprising the steps of:

examining said signal for a noise pulse which exceed certain limits;

determining which datum was present in said binary data at the point in said signal where said noise pulse occurred; and

,

subjecting a predetermined group of data which includes said datum to a test to determine the data'"'"'s correctness and if said predetermined group of data fails said test, inverting the state of said datum.

5. the method defined by claim 4 wherein said test comprises a parity check.

6. The method defined by claims 4 or 5 wherein said test comprises a Hamming code check.

7. In an apparatus for handling a signal representing a stream of bits, a plurality of ones of said bits representing a word and where each of said words includes one or more bits used to detect and correct errors in said word, and improved method comprising the steps of:

detecting noise pulses in said signal which exceed a threshold level;

examining each word to determine if it contains an error; and

,

changing the state of a bit in the ones of said words which contain errors, said bit corresponding to the position along said signal where one of said noise pulses was detected

8. In an apparatus for detecting binary data in a modulated signal, where predetermined groups of bits include Hamming code and a parity bit, an improved method for detecting and correcting errors comprising the steps of:

determining is a single error is present in each of said groups of bits;

correcting said single error using said Hamming code if a single error is detected;

determining if double errors are present in ones of said groups of bits;

examining said modulated signal for noise pulses which exceed certain limits;

determining which of said bits in said groups of bits was detected at the point in said modulated signal where said noise pulses occurred; and

,

correcting said double errors by using Hamming code and by changing the states of said bits detected at the points in said modulated signal where said noise pulses occurred.

9. In an apparatus for handling a signal representing binary data, an improved method for correcting errors in said binary data comprising the steps of:

(a) detecting anomalies in said signal;

(b) identifying the data in said signal associated with the occurrence of said anomalies;

(c) subjecting said data identified in step (b) above to verification using a test independent of said detecting step (a) above; and

,

(d) correcting said data if said data cannot be verified by the verification of step (c) above.

10. In an apparatus for handling a received signal representing a series of binary signals, an improvement for correcting transmission errors in said binary signals comprising:

detection means for detecting anomalies in said received signal; and

,

correction means for changing the state of the ones of said binary signals detected in said received signal where said anomalies occurred, said correction means being coupled to said detection means, said correction means employing a correcting code which is independent of said detection means for detecting anomalies.

11. In an apparatus for handling a modulated signal representing a stream of bits, a plurality of ones of said bits representing a data word, and where one or more bits are included with each of said words to correct errors in said data word, and improvement comprising:

detection means for detecting noise pulses in said modulated signal which exceed certain limits;

verification means for verifying the correctness of said words detected from said modulated signal; and

,

correction means for changing the state of bits in said words that were located in said modulated signal at locations where said noise pulses were detected, said correcting means being coupled to said verification means and said detection means.

12. In an apparatus for handling a signal representing binary data, an improved method for correcting transmission errors comprising the steps of:

detecting anomalies in said signal;

verifying the correctness of said data with a mechanism which is independent of said detecting of said anomalies; and

,

changing the state of the ones of said binary signals detected in said signal occurring where said anomalies are detected, if the correctness of said data cannot be verified.