Packet detection for magnetic storage channels

A read channel design for hard disk drives is presented. By distributing the data processing time over the accessing time, packet detection relaxes the high throughput constraints of high-end disk drives. With the reduced rate channel output, sampling detectors such as a partial response maximum likelihood (PRML) detector and a decision feedback equalizer (DFE) can be implemented via software using digital signal processors (DSPs) depending on the type of channel. A simple data accessing model is offered to provide guidelines for the selection of system parameters. Using a Lorentzian channel model of pw₅₀=3T and a target error rate of 10^-6 the computational complexities of three sampling detectors are found to be under 110 operations per symbol. With the spreading of the signal processing time over the mechanical service time, the detectors operate below 200 million operations per second, which makes software-based DSP implementation possible