Dipulse-response measurement of a magnetic recording channel using Golay complementary sequences

We apply Golay complementary sequences for measuring the dipulse response and transfer functions of a digital magnetic-saturation-recording channel. Our experimental channel suffers from nonlinear distortion caused by a magnetoresistive (MR) sensor. The measured-channel characteristics are compared with the same characteristics obtained by the dipulse-response measurement technique by using feedback-shift register sequences. Based on a practical nonlinear Volterra model of a digital magnetic-saturation-recording channel, we analyze the artifacts caused by second- and third-order nonlinear distortion, which do-occur in the Golay dipulse responses and transfer functions. We show that with either of the considered dipulse-response measurement techniques, the artifacts caused by even-order nonlinear distortion, which occur in the measured-channel characteristics, can easily be removed. The measured-channel characteristics obtained show excellent performance for either of the considered excitation sequences.