Vector Signaling Code with Improved Noise Margin
First Claim
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1. A system comprising:
- a plurality of conductors configured to receive a set of input data bits;
a pre-encoder configured to map the set of input data bits into symbols of a pre-code codeword of a pre-code, wherein the pre-code comprises a constrained set of vectors determined from a maximal set of vectors, and wherein the pre-code is associated with a constrained post-transformation alphabet comprising a portion of low magnitude symbol values selected from an unconstrained post-transformation alphabet associated with the maximal set of vectors;
an encoder configured to generate a constrained-alphabet codeword of a constrained-alphabet vector signaling code, the constrained-alphabet codeword representing a transformation of the pre-code codeword with a first non-simple orthogonal matrix, wherein the constrained-alphabet codeword comprises symbols of the constrained post-transformation alphabet; and
,a driver configured to transmit the constrained-alphabet codeword on a multi-wire communication bus.
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Abstract
Methods are described allowing a vector signaling code to encode multi-level data without the significant alphabet size increase known to cause symbol dynamic range compression and thus increased noise susceptibility. By intentionally restricting the number of codewords used, good pin efficiency may be maintained along with improved system signal-to-noise ratio.
121 Citations
20 Claims
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1. A system comprising:
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a plurality of conductors configured to receive a set of input data bits; a pre-encoder configured to map the set of input data bits into symbols of a pre-code codeword of a pre-code, wherein the pre-code comprises a constrained set of vectors determined from a maximal set of vectors, and wherein the pre-code is associated with a constrained post-transformation alphabet comprising a portion of low magnitude symbol values selected from an unconstrained post-transformation alphabet associated with the maximal set of vectors; an encoder configured to generate a constrained-alphabet codeword of a constrained-alphabet vector signaling code, the constrained-alphabet codeword representing a transformation of the pre-code codeword with a first non-simple orthogonal matrix, wherein the constrained-alphabet codeword comprises symbols of the constrained post-transformation alphabet; and
,a driver configured to transmit the constrained-alphabet codeword on a multi-wire communication bus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method comprising:
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receiving a set of input data bits on a plurality of conductors; mapping the set of input data bits into symbols of a pre-code codeword of a pre-code, the pre-code corresponding to a constrained set of vectors determined from a maximal set of vectors; generating a constrained-alphabet codeword comprising elements of a constrained alphabet, the constrained-alphabet codeword representing a transformation of the pre-code codeword with a non-simple orthogonal matrix, wherein the constrained alphabet comprises a number m of low magnitude symbol values, the number m less than a total number n of symbol values in an unconstrained alphabet generated by transforming the maximal set of vectors with the non-simple orthogonal matrix, and wherein n and m are integers, n greater than 1 and m greater than 2; and
,transmitting the constrained-alphabet codeword. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification