Generation of trellis-coded modulation schemes

An apparatus for generating a Trellis-Coded Modulation (TCM) scheme for transmitting symbols over a Partial-Response (PR) channel, the apparatus comprising:

• a memory, configured to hold a base TCM scheme comprising a plurality of states and transitions among the states;
• and
• a processor, configured to:
• produce multiple first sequences of symbols, and calculate respective second sequences of symbols, each second sequence of symbols emulating a response of the PR channel to a respective first sequence of symbols traversing the PR channel;
• initialize the TCM scheme, in the memory, by assigning the first sequences of symbols to the transitions of the base TCM scheme;
• remove one or more of the transitions from the TCM scheme in a manner that remaining second sequences from among the second sequences of symbols, the remaining second sequences corresponding to transitions that were not removed, are separated from one another by at least a specified first distance;
• and
• further remove, from among the transitions of the TCM scheme, one or more additional transitions, in a manner that a plurality of sequences from among the remaining second sequences of symbols, the plurality corresponding to transitions from a current state to a next state, are separated from one another by at least a specified second distance larger than the first distance.

A computer software product for generating a Trellis-Coded Modulation (TCM) scheme for transmitting symbols over a Partial-Response (PR) channel, the product comprising a tangible non-transitory computer-readable medium in which program instructions are stored, which instructions, when read by a processor of a computing system, cause the processor to hold in a memory of the computing system a base TCM scheme comprising a plurality of states and transitions among the states, to produce multiple first sequences of symbols, and calculate respective second sequences of symbols, each second sequence of symbols emulating a response of the PR channel to a respective first sequence of symbols traversing the PR channel, to initialize the TCM scheme, in the memory, by assigning the first sequences of symbols to the transitions of the base TCM scheme, to remove one or more of the transitions from the TCM scheme in a manner that remaining second sequences from among the second sequences of symbols, the remaining second sequences corresponding to transitions that were not removed, are separated from one another by at least a specified first distance, and to further remove, from among the transitions of the TCM scheme, one or more additional transitions, in a manner that a plurality of sequences from among the remaining second sequences of symbols, the plurality corresponding to transitions from a current state to a next state, are separated by at least a specified second distance larger than the first distance.