Vector Signaling Codes with Increased Signal to Noise Characteristics

摘要

Vector signaling codes are synergistically combined with multi-level signaling, the increased alphabet size provided by the multi-level signaling enabling a larger codeword space for a given number of symbols, at the cost of reduced receiver detection margin for each of the multiple signal levels. Vector signaling code construction methods are disclosed in which code construction and selection of multi-level signal levels are coordinated with the design of an associated receive comparator network, wherein modified signal levels encoded and emitted by the transmitter result in increased detection margin at the receive comparators.

主权项

1. An apparatus comprising:
a multi-wire bus configured to receive a set of symbols of a codeword, the set of symbols representing a weighted sum of sub-channel code vectors, each sub-channel code vector weighted according to a corresponding antipodal weight of a set of antipodal weights, the set of antipodal weight set containing at least two unique magnitudes, wherein the sub-channel code vectors are mutually orthogonal, and wherein the sub-channel code vectors form a scaled-orthogonal matrix; a decoder, connected to the multi-wire bus, comprising a plurality of sub-channel comparators configured to generate a respective plurality of comparator output values based on the received set of symbols of the codeword, each comparator comprising a set of chi-normalized input weights, wherein each set of chi-normalized input weights is selected according to a respective sub-channel code vector, and wherein the antipodal weight set is selected such that each subchannel comparator generates antipodal values greater than a minimum value.