Patent ID: 6995694

Claim:
An encoder, comprising: a) a detector configured to identify each of a plurality of x-unit sequence values of an N-ary sequence, where x and N are each an integer of at least 2; b) a converter configured to convert each of said x-unit N-ary sequence values to a y-unit M-ary sequence value, where y and M are each an integer of at least 2 and M y >N x ; c) coding constraint logic configured to (i) determine whether an M-ary sequence output from said converter conforms to a coding constraint for said M-ary sequence and (ii) instruct said converter to output (1) a member of a first subset of y-unit M-ary sequence values when said M-ary sequence conforms to said coding constraint and (2) a member of a second subset of y-unit M-ary sequence values when said M-ary sequence violates said coding constraint, each of said y-unit M-ary sequence values in said second subset being distinct from said y-unit M-ary sequence values in said first subset.