A trellis-coded E/sup 2/PRML digital read/write channel IC

Partial response (PR) signaling with maximum likelihood (ML) detection is now a well-entrenched technology in magnetic disk drive systems. Indeed, read channel products using Extended Partial Response (EPR) systems are ubiquitous in commercially available disk drive products. Efforts are now underway to implement even more advanced detection methods that combine EPR systems with trellis coding techniques to provide higher recording densities or to operate with a lower SNR for a given bit error rate (EPR). This paper describes one such method, which is referred to as TC-E/sup 2/PRML. TC-E/sup 2/PRML is based on the idea of jointly designing the coding and the equalization functions to achieve improved utilization of the available SNR and bandwidth of the head/media combination. Its SNR performance is superior to that of the previous generation PRML or EPRML channels over the linear densities of current and future interest (PW50/T>3.0).