Method for detecting data encoded as state transitions in a read signal
AssigneeSeagate Technology LLC
InventorsJones V. Howell, Leroy J. Thompson, Gregory A. Unruh
Life of this patent
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Abstract
A data detection circuit for a read channel that recovers data encoded as the presence or absence of flux transitions on a magnetic recording medium, compares a current data sample of a read signal with a previous data sample and a threshold to determine whether the previous data sample represents a flux transition. The use of two data samples in the determination of flux transitions provides a more accurate detection of the data than comparing a single data sample to a threshold value. The data detection circuit generates an output data signal having data values based on the determined flux transitions of the data samples.
Claims4
A method of calibrating a variable delay in a read channel having a peak-to-peak amplitude detector that detects the amplitude of a read signal recovered from a recording medium, and a phase locked loop that generates a read clock signal from the read signal, the method comprising:
- inverting the read clock signal;
- passing a fixed data pattern through the read channel and synchronizing the phase locked loop to the fixed data pattern;
- monitoring an output of the amplitude detector;
- adjusting the variable delay so that the amplitude detector detects a minimum amplitude of the read signal;
- and
- re-inverting the inverted read clock signal such that the amplitude detector detects a maximum amplitude of the read signal.
Dependencies are inferred from the claim text.