Signal-to-noise ratio (SNR) considerations due to the equalization of a partial response magneto-optical read channel

The inherently high storage densities available using magneto-optic (MO) recording systems can be further enhanced by application of partial response signaling. In order to achieve this, equalization of the read channel is required to shape the channel to give the desired class 1 partial response. A number of analog and digital (FIR) equalizer functions are derived, and their performances assessed in terms of improved SNR due to increased resolution of the signaling. It is concluded that FIR filtering is superior to the low pass analog filtering used. Given typical figures for noise levels within a MO drive, it is verified that it is possible to push the recording density of the system up to the maximum achievable with this technique and still retain reasonable soft error rates