Rate 16/17 ENDEC with independent high/low byte decoding
First Claim
1. A 16/17 ENDEC for decoding a 17-bit codeword into a 16-bit data word, comprising a decoder for decoding a predetermined first number of bits out of the 17-bit codeword into an 8-bit high byte of the data word and for decoding a predetermined second number of bits out of the 17-bit codeword into an 8-bit low byte of the data word, wherein:
- (a) the decoder decodes the high byte of the data word independent from decoding the low byte of the data word, and the decoder decodes the low byte of the data word independent from decoding the high byte of the data word; and
(b) errors in decoding the high byte of the data word do not induce errors in decoding the low byte of the data word, and errors in decoding the low byte of the data word do not induce errors in decoding the high byte of the data word.
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Accused Products
Abstract
A rate 16/17 ENDEC is disclosed which encodes 16 bit input data words into 17 bit codewords according to at least one predetermined code constraint, such as an RLL (d,k) constraint. The encoder encodes the high and low byte of the input data word using the same mapping circuitry which reduces its cost and complexity. The codewords are transferred through a communication channel, such as a computer disc storage device, and upon reception (or readback) the first 8 bits of the 17 bit codeword are decoded independent from the last 8 bits which prevents error propagation. That is, the first 8 bits of the codeword are decoded into a high byte of the decoded data word, and the last 8 bits of the codeword are decoded into a low byte of the decoded data word independent from one another. Thus, errors that occur in the received data sequence which affect only the first 8 bits of the codeword will not propagate to the decoded low byte, and errors affecting only the last 8 bits of the codeword will not propagate to the decoded high byte. Furthermore, the decoder uses the same mapping circuitry to decode the low and high byte of the output data words, thereby reducing its cost and complexity.
14 Citations
16 Claims
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1. A 16/17 ENDEC for decoding a 17-bit codeword into a 16-bit data word, comprising a decoder for decoding a predetermined first number of bits out of the 17-bit codeword into an 8-bit high byte of the data word and for decoding a predetermined second number of bits out of the 17-bit codeword into an 8-bit low byte of the data word, wherein:
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(a) the decoder decodes the high byte of the data word independent from decoding the low byte of the data word, and the decoder decodes the low byte of the data word independent from decoding the high byte of the data word; and (b) errors in decoding the high byte of the data word do not induce errors in decoding the low byte of the data word, and errors in decoding the low byte of the data word do not induce errors in decoding the high byte of the data word. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for decoding a 17-bit codeword into a 16-bit data word, comprising the steps of:
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(a) first decoding a predetermined first number of bits out of the 17-bit codeword into an 8-bit first byte of the data word; (b) second decoding a predetermined second number of bits out of the 17-bit codeword into an 8-bit second byte of the data word, wherein the second decoding operates independent from the first decoding such that errors in decoding the first byte of the data word do not induce errors in decoding the second byte of the data word. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification