A new DC- and Nyquist-free trellis code for partial response class-I and class-II channels

A 16/20 (0, 6) dc- and Nyquist-free trellis code for the partial response class-I (PR1) and class-II (PR2) channels has been developed. With a Lorentzian pulse, this code showed a coding gain of 1.2 dB for the PR1 channel and 2.2 db for the PR2 channel at a user bit density of 3.0, compared with the conventional 16/17 (0, 6/6) run-length limited code for the extended partial response class-IV (EPR-I) channel in error-rate simulation. With a pulse with dc response, this code showed a coding gain of 0.5 dB for the PR1 channel and 2.4 dB for the PR2 channel at the user bit density, compared with the 16/17 code for the EPR4 channel.