A new code is presented which improves the minimum distance properties
of sequence detectors operating at high linear densities. This code,
which is called the maximum transition run code, eliminates data patte
rns producing three or more consecutive transitions while imposing the
usual k-constraint necessary for timing recovery. The code possesses
the similar distance-gaining property of the (1,k) code, but can be im
plemented with considerably higher rates. Bit error rate simulations o
n fixed delay tree search with decision feedback and high order partia
l response maximum likelihood detectors confirm large coding gains ove
r the conventional (0,k) code.