Byte-wide encoder and decoder system for RLL (1,7) code
First Claim
1. A system for encoding an input byte-wide data stream into an output run-length-limited (RLL) symbol string or for decoding an output byte-wide data stream from an input RLL symbol string, comprising:
- RLL encoder means responsive to consecutive, unencoded parallel bytes occurring at a byte rate fB in an input byte-wide data stream for producing a first RLL (1,7) symbol sequence including consecutive groups of parallel RLL symbols, each of said bytes including at least eight bits;
format means responsive to a mode control signal and connected to said RLL encoder means for operating in a first mode by receiving said first RLL symbol sequence at said byte rate fB and converting said first RLL (1,7) symbol sequence into an output RLL symbol string having a symbol string rate fC =N×
fB, where N is a whole number which is greater than 1, or for operating in a second mode by receiving an input RLL symbol string having said symbol string rate fC and providing, at said byte rate, a second RLL (1,7) symbol sequence including consecutive groups of parallel RLL symbols;
RLL decoder means responsive to said second RLL (1,7) symbol sequence for providing an output byte-wide data stream including consecutive, decoded parallel bytes of data occurring at said byte rate fB, each of said decoded bytes comprising at least eight bits; and
mode control means for conditioning said mode control signal to operate said format means in either said first mode or said second mode according to a predetermined external condition.
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Abstract
A system for encoding consecutive parallel bytes of source data into an RLL (1,7) output symbol string and decoding an input RLL (1,7) symbol string to produce an output sequence of parallel bytes of data. The system accepts an input sequence of parallel data bytes occurring at a byte rate and provides, in response, the output RLL symbol string at a symbol string rate which is twelve times the byte rate. Similarly, the output byte sequence has a byte rate which is 1/12 of the input RLL symbol string rate. The system performs RLL encoding and decoding at the byte rate, thus eliminating the odd 2/3 fC source clock required in systems performing RLL coding and decoding functions on a bit-by-bit basis.
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Citations
13 Claims
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1. A system for encoding an input byte-wide data stream into an output run-length-limited (RLL) symbol string or for decoding an output byte-wide data stream from an input RLL symbol string, comprising:
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RLL encoder means responsive to consecutive, unencoded parallel bytes occurring at a byte rate fB in an input byte-wide data stream for producing a first RLL (1,7) symbol sequence including consecutive groups of parallel RLL symbols, each of said bytes including at least eight bits; format means responsive to a mode control signal and connected to said RLL encoder means for operating in a first mode by receiving said first RLL symbol sequence at said byte rate fB and converting said first RLL (1,7) symbol sequence into an output RLL symbol string having a symbol string rate fC =N×
fB, where N is a whole number which is greater than 1, or for operating in a second mode by receiving an input RLL symbol string having said symbol string rate fC and providing, at said byte rate, a second RLL (1,7) symbol sequence including consecutive groups of parallel RLL symbols;RLL decoder means responsive to said second RLL (1,7) symbol sequence for providing an output byte-wide data stream including consecutive, decoded parallel bytes of data occurring at said byte rate fB, each of said decoded bytes comprising at least eight bits; and mode control means for conditioning said mode control signal to operate said format means in either said first mode or said second mode according to a predetermined external condition. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for converting a sequence of groups of unconstrained parallel bits having a group sequence rate into a fixed-rate, run-length-limited (RLL) (1,7) symbol string or for converting a fixed rate RLL (1,7) symbol string into a sequence of groups of unconstrained, parallel bits having said group sequence rate according to a predetermined external condition, comprising:
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RLL encoding means for receiving an input bit group sequence including a sequence of groups of at least eight parallel bits that is input into said apparatus at a group sequence rate fB and for encoding, at said group sequence rate fB, the input bit group sequence to produce a first RLL symbol group sequence including a sequence of groups of parallel RLL (1,7) symbols; RLL decoding means for receiving a second RLL symbol group sequence including a sequence of groups of parallel RLL (1,7) symbols and for decoding, at said group sequence rate fB, said second RLL symbol group sequence into an output bit group sequence including a sequence of groups of at least eight parallel bits that is output by said apparatus at said group sequence rate; format conversion means connected to said RLL encoder means and to said RLL decoder means for operating in a first mode by converting said first RLL symbol group sequence into an output RLL (1,7) symbol string output by said apparatus at a symbol string rate fC =N×
fC, where N is a whole number which is greater than 1, or for operating in a second mode by converting an input RLL (1,7) symbol string that is input to said apparatus at said symbol string rate fC into said second RLL symbol group sequence and providing said second RLL symbol group sequence to said RLL encoding means; andmode control means connected to said format conversion means for conditioning said format means to operate in said first mode or said second mode according to said predetermined external condition. - View Dependent Claims (9, 10, 11, 12, 13)
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Specification