Rate 8/9 sliding block distance-enhancing code with stationary detector

A new distance-enhancing code for partial-response magnetic recording chann els eliminates most frequent errors, while keeping the two-step code trelli s time invariant, Recently, published trellis codes either have lower code rates or result in time-varying trellises with a period of nine, thus requi ring a higher complexity of detectors and code synchronization. The new cod e introduces dependency between code words in order to achieve the same cod ing constraints as the 8/9 time-varying maximum transition runlength (TMTR) code, with the same code rate, but resulting in a trellis that has a perio d of 2, This code has been applied to the E(2)PR4 and a 32-state generalize d partial response (GPR) ISI target. The resulting two-step trellises have 14 and 28 states, respectively. Coding gain is demonstrated for both target s in additive white Gaussian noise.