Abstract: A system and method employing a rate 16/17 (0,5) code constructed in accordance with a set of pivot bits and a set of corrections for predefined code violations limits the number of consecutive zeros seen by a channel to five. The rate 16/17 (0,5) code is suitable for magnetic or similar recording media and may be employed in partial response maximum likelihood read channels. A feature of the constructed code is a high transition density which allows for more frequent timing and gain control updates, which results in lower required channel input signal to noise ratio for a given channel performance. Each constructed codeword is block encodable and block decodable, and the code construction allows for efficient circuit implementation in both an encoder and a decoder.

Abstract: An analog, adaptive generalized transversal equalizer for use in the filtering system of a disc drive PRML read channel, the transversal equalizer employing the use of non-ideal delay elements. The filtering system comprises the equalizer connected in series with an adaptive, analog prefilter. The prefilter is comprised of a plurality of serially connected, adaptive, analog filter stages having variable transfer functions determined by adaptive parameter signals received by the filter stages. The generalized transversal equalizer comprises a plurality of serially connected, adaptive, analog low pass filters, having taps on either side of each low pass filter, a plurality of multipliers that receive signals at the tap locations of the delay circuit, and a summing circuit that receives the outputs of the multipliers.

Abstract: A disc drive system includes a plurality of subsystems. At least one of the subsystems includes a filter which is completely integrated using a synthetic integrated circuit element.

Abstract: An adaptive, analog filter system of a PRML [PARTIAL RESPONSE MAXIMUM LIKELIHOOD ] read channel of a disc drive comprising an adaptive, analog transversal equator connected in series with an adaptive, analog prefilter. The prefilter is comprised of a plurality of serially connected, adaptive, analog filter stages having variable transfer functions determined by adaptive parameter signals received by the filter stages. The transversal equalizer is comprised of a delay circuit, comprised of a plurality of serially connected, adaptive, analog sixth order low pass filters, that is tapped to either side of each low pass filter, a plurality of analog multipliers that receive signals at the tap locations of the delay circuit, and a summing circuit that receives the outputs of the multipliers.

Abstract: Method and apparatus for controlling the timing of the sampling of signals and signal amplitude in a PRML read channel. A VCO generates a read clock and a clock generator connected to the VCO generates even and odd clock signals corresponding to even and odd cycles of operation of the VCO. Serially connected even sample and hold circuits respond to clock signals to store samples of the read channel signal taken during successive odd cycles and serially connected odd sample and hold circuits store samples taken during successive even cycles. Comparator circuits compare the samples taken in each cycle to reference signals and the comparisons are clocked through two stage, even and odd shift registers to provide estimates of the presence or absence of nonzero samples for each even and odd cycle.

Abstract: A disc drive system includes a plurality of subsystems. At least one of the subsystems includes a filter which is completely integrated using a synthetic integrated circuit element.