Abstract: A phase error estimate value between an actual interpolated sample time and an ideal interpolated sample time of an analog signal is selected by circuitry based on a quotient (z2−z0)/(z3−z1), where z0, z1, z2, and z3 are four successive synchronous samples of the analog signal. A sign of the phase error estimate value is selected by circuitry based on a comparison of predetermined differences between the four successive synchronous samples. The phase error estimate value can be adjusted by circuitry when an absolute value of the phase error estimate value exceeds a predetermined threshold and a closest sampling phase according to a difference between (z2−z0) and (z3−z1) differs from a phase predicted by a hysteresis state.

Abstract: A quotient (y2−y0)/(y3−y1) is generated by circuitry where Yk are asynchronous samples from a sequence of asynchronous samples, the quotient (y2−y0)/(y3−y1) is compared to a plurality of predetermined fractions with a comparator, and an initial interpolation interval value (&mgr;0) stored in a lookup table is selected by circuitry based on the comparison of the quotient to the plurality of predetermined fractions. The predetermined fractions can represent boundary points and the quotient can fall between an interval defined by two of the boundary points. The selected initial interpolation value (&mgr;0) can be the average of two calculated values of (&mgr;) using values of two predetermined fractions associated with the two boundary points between which the quotient falls.

Abstract: Synchronous acquisition in a sampled amplitude read channel. A timing error estimation unit (302) is provided to calculate an acquisition timing error. The estimate is based on use of synchronous (interpolated) samples and an approximation to an arctangent function.

Abstract: Synchronous acquisition in a sampled amplitude read channel. A timing error estimation unit (302) is provided to calculate an acquisition timing error. The estimate is based on use of synchronous (interpolated) samples and an approximation to an arctangent function.

Abstract: An improved sampled amplitude read/write channel is provided. The system is an integrated Generalized Partial Response Maximum Likelihood (GPRML) read channel incorporating Read, Write, and Servo modes of operation. One implementation includes a 32/34 rate parity code and matched Viterbi detector, a 32 state Viterbi detector optimal parity processor, robust frame synchronization, self-adaptive equalization, thermal asperity detection and compensation, adaptive magneto-resistive asymmetry compensation, low latency interpolated timing recovery and programmable write precompensation.

Abstract: An improved zero phase restart circuit (308). A lookup table technique is employed to avoid an extensive series of calculations.

Abstract: A zero phase restart circuit (308) estimates a quotient (y2−y0/(y3−Y1), where yk are asynchronous samples of a sequence. The quotient is compared to one or more predetermined fractions, and the interpolation interval is determined by examining between which predetermined fractions the interpolation interval lies. This lookup table technique can avoid an extensive series of calculations.

Abstract: An improved sampled amplitude read/write channel is provided. The system is an integrated Generalized Partial Response Maximum Likelihood (GPRML) read channel incorporating Read, Write, and Servo modes of operation. One implementation includes a 32/34 rate parity code and matched Viterbi detector, a 32 state Viterbi detector optimal parity processor, robust frame synchronization, self-adapive equalization, thermal asperity detection and compensation, adaptive magneto-resistive asymmetry compensation, low latency interpolated timing recovery and programmable write precompensation.