SUMMARY

In certain embodiments, an apparatus may comprise a continuous time front end (CTFE) circuit. The CTFE circuit may be configured to receive an analog read signal corresponding to a grain patterned medium having servo wedges and data areas with a same grain pattern density and process the analog signal to generate a modified analog signal. The apparatus may also include an analog to digital converter (A/D) circuit configured to receive the modified analog signal and generate digital samples from the modified analog signal. The apparatus may also include a phase locked loop (PLL) circuit configured to generate a first clock signal and a first digital phase converter (DPC) circuit configured to generate a second clock signal by phase shifting the first clock signal based on an applied control signal and provide the second clock signal to the A/D circuit to control the generating of the digital samples. The apparatus may also include a write channel configured to synchronously write data to the data areas of the grain patterned medium based on the second clock signal and a servo channel configured to read servo information from a servo wedge based on the second clock signal.

In certain embodiments, a method may comprise writing, on a grain patterned medium, a data area with a known data pattern, performing a read of the data area to obtain a detected bit sequence, determining a deviation between the detected bit sequence and the known data pattern, determining a count of media patterns within the data area based on the deviation, and storing the count of media patterns to enable synchronous writing of the grain patterned media.

In certain embodiments, an apparatus may comprise an integrated circuit including a detector circuit configured to detect a bit sequence read from a patterned medium and a data generator circuit coupled to a delay line and configured to generate bits of a known data pattern. The integrated circuit may also include: multiple bit-error counters coupled to the delay line and each configured to compare a bit or shifted bit of the known data pattern to a bit of the detected bit sequence and count a number of bit-errors over a period of time; a control circuit configured to count a number of bits processed by the bit-error counters; multiple registers, each of the multiple registers configured to store a result of a corresponding bit-error counter over the period of time; and an adjustment circuit configured to modify a count of grain patterns between two servo wedges of the patterned medium based on the results of the bit-error counters stored in the registers, the adjustment circuit further configured to store the modified count of grain patterns to enable synchronous writing of the grain patterned medium.

In certain embodiments, an apparatus comprising a control circuit configured to: manage read operations and write operations to a grain patterned data storage medium having a track with a homogenous media feature pattern for the entirety of the track, the track including a servo region and a data region; and adjust a clock frequency and phase based on a read in the servo region to maintain a desired alignment for a write in the data region. The apparatus may also include a single, common clock utilized for all write operations and read operations to both the servo region and the data region.

