Two-dimensional magnetic recording reader offset estimation

A reader offset estimation apparatus for enhancing read performance in a multi-reader two-dimensional magnetic recording system including at least first and second readers, the reader offset estimation apparatus comprising:

• at least one interpolation filter, the at least one interpolation filter receiving a first digital signal indicative of a first analog read signal from the first reader and a second digital signal indicative of a second analog read signal from the second reader, each of the first and second digital signals being indicative of a value of the first and second analog read signals, respectively, at an integer multiple of a corresponding sampling period associated therewith, the at least one interpolation filter being operative to generate first and second interpolated signals, each of the first and second interpolated signals being indicative of a value of the first and second digital signals, respectively, at an arbitrary point in time between integer multiples of the corresponding sampling period;
• and
• at least one correlator coupled with the at least one interpolation filter, the at least one correlator being operative to combine at least one of the first and second interpolated signals and the first and second digital signals to thereby generate a reader offset estimation signal for enhancing read performance in the multi-reader two-dimensional magnetic recording system.

A method for enhancing read performance in a multi-reader two-dimensional magnetic recording system including at least first and second readers, the method comprising:

• receiving a first analog read signal from the first reader and a second analog read signal from the second reader;
• sampling the first and second analog read signals to generate first and second sampled signals, respectively, each of the first and second sampled signals comprising at least one of an integer component, indicative of a value of a corresponding one of the first and second analog read signals, respectively, at an integer multiple of a corresponding sampling period associated therewith, and a fractional component, indicative of a value of a corresponding one of the first and second analog read signals, respectively, at an arbitrary point in time between integer multiples of the corresponding sampling period;
• wherein interpolating the first digital signal is performed sequentially for a plurality of phase values to which the first analog read signal is to be interpolated to thereby generate a plurality of corresponding fractional components, each of the fractional components being generated during a given interpolation period as a function of a corresponding one of the phase values used during the given interpolation period;
• and
• combining at least one of the integer and fractional components of the respective first and second sampled signals to thereby generate a reader offset estimation signal for enhancing read performance in the multi-reader two-dimensional magnetic recording system.

A method for enhancing read performance in a multi-reader two-dimensional magnetic recording system including at least first and second readers, the method comprising:

• receiving a first analog read signal from the first reader and a second analog read signal from the second reader;
• sampling the first and second analog read signals to generate first and second sampled signals, respectively, wherein sampling each of the first and second input signals includes:
• converting at least the first analog read signal to a first digital signal having a first sampling period associated therewith;
• interpolating the first digital signal using a plurality of interpolation filters, wherein each of the interpolation filters receiving, at a first input, a corresponding value of a phase to which the first analog read signal is to be interpolated, and receiving, at a second input, a readback signal from the first reader, and wherein interpolating the first digital signal yields the fractional component indicative of the value of the first analog read signal at an arbitrary point in time between integer multiples of the first sampling period;
• wherein each of the first and second sampled signals comprising at least one of an integer component, indicative of a value of a corresponding one of the first and second analog read signals, respectively, at an integer multiple of a corresponding sampling period associated therewith, and a fractional component, indicative of a value of a corresponding one of the first and second analog read signals, respectively, at an arbitrary point in time between integer multiples of the corresponding sampling period;
• and
• combining at least one of the integer and fractional components of the respective first and second sampled signals to thereby generate a reader offset estimation signal for enhancing read performance in the multi-reader two-dimensional magnetic recording system.

A method for enhancing read performance in a multi-reader two-dimensional magnetic recording system including at least first and second readers, the method comprising:

• receiving a first analog read signal from the first reader and a second analog read signal from the second reader;
• sampling the first and second analog read signals to generate first and second sampled signals, respectively, each of the first and second sampled signals comprising at least one of an integer component, indicative of a value of a corresponding one of the first and second analog read signals, respectively, at an integer multiple of a corresponding sampling period associated therewith, and a fractional component, indicative of a value of a corresponding one of the first and second analog read signals, respectively, at an arbitrary point in time between integer multiples of the corresponding sampling period;
• combining at least one of the integer and fractional components of the respective first and second sampled signals to thereby generate a reader offset estimation signal for enhancing read performance in the multi-reader two-dimensional magnetic recording system;
• and
• wherein the steps of sampling and combining comprise:
• correlating a first readback signal from the first reader and a second readback signal from the second reader and generating a correlated signal as a function of the first and second readback signals;
• and iteratively performing fractional delay filtering on the correlated signal, a number of iterations of the fractional delaying filtering corresponding to a number of phase values used in the fractional delay filtering.

A method for enhancing read performance in a multi-reader two-dimensional magnetic recording system including at least first and second readers, the method comprising:

• receiving a first analog read signal from the first reader and a second analog read signal from the second reader;
• sampling the first and second analog read signals to generate first and second sampled signals, respectively, each of the first and second sampled signals comprising at least one of an integer component, indicative of a value of a corresponding one of the first and second analog read signals, respectively, at an integer multiple of a corresponding sampling period associated therewith, and a fractional component, indicative of a value of a corresponding one of the first and second analog read signals, respectively, at an arbitrary point in time between integer multiples of the corresponding sampling period;
• combining at least one of the integer and fractional components of the respective first and second sampled signals to thereby generate a reader offset estimation signal for enhancing read performance in the multi-reader two-dimensional magnetic recording system;
• and
• delaying the second sampled signal, an amount of delay being controlled as a function of the reader offset estimation signal.

A method for enhancing read performance in a multi-reader two-dimensional magnetic recording system including at least first and second readers, the method comprising:

• receiving a first analog read signal from the first reader and a second analog read signal from the second reader;
• sampling the first and second analog read signals to generate first and second sampled signals, respectively, each of the first and second sampled signals comprising at least one of an integer component, indicative of a value of a corresponding one of the first and second analog read signals, respectively, at an integer multiple of a corresponding sampling period associated therewith, and a fractional component, indicative of a value of a corresponding one of the first and second analog read signals, respectively, at an arbitrary point in time between integer multiples of the corresponding sampling period;
• combining at least one of the integer and fractional components of the respective first and second sampled signals to thereby generate a reader offset estimation signal for enhancing read performance in the multi-reader two-dimensional magnetic recording system, wherein combining the at least one of the integer and fractional components of the respective first and second sampled signals includes selecting a signal path having a largest correlation peak value among a plurality of phase values to which the first analog read signal is to be interpolated.