The performance of noise predictive maximum likelihood(NPML)system in a perpendicular magnetic recording channel with jitter-like media noise is studied. The bit error rates of NPML systems for the PR2, E^2PR3 and E^2PR4 channels are obtained by computer simulation and theoretical method. The relationship between the ratio R_J of the jitter-like media noise power to the total noise power at the reading point and the required SNR to achieve a bit error rate of 10^<-4> is also obtained and compared with that of the conventional PRML system. The results show that the SNR improvements of NPML systems over PRML systems are about 2.1, 2.8 and 5.6 dB for the PR2, E^2PR3 and E^2PR4 channels, respectively, at a normalized linear density of 1.5 and R_J=50%.
