Timing loop

A system for recovering a data signal including:

• a processor configured to:
• receive an input signal from a magnetic recording channel;
• use an analog to digital converter (ADC) to sample the input signal according to a sampling clock having a sampling phase wherein the sampling phase is determined at least in part by comparing, during tracking, the sampled input signal output by the analog to digital converter to a signal associated with a decision;
• and
• filter the sampled input signal output by the analog to digital converter using an equalization filter that is trained to match an adaptive target filter that is not predetermined, wherein coefficients of the adaptive target filter and the equalization filter are jointly optimized, the adaptive target filter being external to the equalization filter;
• and
• a memory coupled with the processor, wherein the memory provides the processor with instructions.

A computer program product for recovering a data signal, the computer program product being embodied in a non-transitory computer readable storage medium and comprising computer instructions which when executed cause a computer to:

• receive an input signal from a magnetic recording channel;
• use an analog to digital converter (ADC) to sample the input signal according to a sampling clock having a sampling phase wherein the sampling phase is determined at least in part by comparing, during tracking, the sampled input signal output by the analog to digital converter to a signal associated with a decision;
• and
• filter the sampled input signal output by the analog to digital converter using an equalization filter that is trained to match an adaptive target filter that is not predetermined, wherein coefficients of the adaptive target filter and the equalization filter are jointly optimized, the adaptive target filter being external to the equalization filter.