Adjustable error-correction composite Reed-Solomon encoder/syndrome generator
First Claim
1. An algebraic error correction system, comprising:
- a composite encoder/syndrome generating circuit for generating both check symbols and error syndromes, said circuit comprising a single set of multiplier devices that have tap weights with preselected values for computing the check symbols and also computing the error syndromes used to determine error locations and values, the complete set of multiplier devices providing a maximum preselected error correction capability; and
means for selectively adjusting the number of said multiplier devices from the set included in said circuit to provide a desired error correction capability less than said maximum capability without requiring changes in the values of the tap weights.
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Abstract
A composite encoder/syndrome generating circuit computes both check symbols and error syndromes using a single set of multiplier devices with varying tap weights having values that provide a maximum preselected error correction capability but is readily adjustable, such as by programmable latches, to eliminate from the circuit selectable multiplier devices to reduce the error correction capability without requiring a change in the tap weight values. The circuit may be used to increase or decrease error correction capability (a) according to which of a plurality of concentric bands of recording tracks is being accessed in a banded direct access data storage device, (b) according to noise level as sensed in a data communications channel having an output subject to noise, or (c) according to changes in sending rates in a sending device that sends data at variable rates.
98 Citations
9 Claims
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1. An algebraic error correction system, comprising:
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a composite encoder/syndrome generating circuit for generating both check symbols and error syndromes, said circuit comprising a single set of multiplier devices that have tap weights with preselected values for computing the check symbols and also computing the error syndromes used to determine error locations and values, the complete set of multiplier devices providing a maximum preselected error correction capability; and means for selectively adjusting the number of said multiplier devices from the set included in said circuit to provide a desired error correction capability less than said maximum capability without requiring changes in the values of the tap weights. - View Dependent Claims (2, 3, 4)
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5. A method of adjusting error correction capability in at least one system from a group of systems including a direct access storage system, data communications system, or data network system, including the steps of:
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providing in a circuit a single set of multiplier devices with tap weights having values preselected for computing values for both check symbols and for error syndromes necessary to determine error locations and values for providing a maximum preselected error correction capability; and selectively adjusting the number of said multiplier devices included in the circuit to provide a desired error correction capability less than said maximum capability without requiring changes in the values of the tap weights.
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6. A data processing system comprising:
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a controller; a channel; a buffer; a decoder; a circuit comprising means operative during an encoding operation to generate check symbols and during a decoding operation to generate error syndromes, said circuit comprising; (i) multiplier devices that have tap weights with preselected values for computing the check symbols and also computing the error syndromes for providing a maximum preselected error correction capability when all of said multiplier devices are included in the circuit; and (ii) means for selectively adjusting the number of said multiplier devices included in said circuit to provide a desired error correction capability less than said maximum capability without requiring changes in the values of the tap weights; and means (39A, 39B, 39C, 42, 43,
44) conditioned by said controller to select between encoding and decoding operations and, for either of these operations, between either of two operating conditions for said circuit, said circuit being operative while in one condition during an encoding operation to pass data to the channel and generate the check symbols and while in the other condition during the encoding operation to pass the check bytes to the channel, said circuit being operative while in said one condition during a decoding operation to pass data from the channel to the buffer and generate the error syndromes, and while in said other position during the decoding operation to pass the error syndromes to the decoder. - View Dependent Claims (7, 8, 9)
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Specification