Self-synchronization in a magnetic recording channel utilizing

Abstract

Improved self-synchronization in a sampled magnetic recording channel employing time-domain equalization. The channel includes a time-domain equalizer which filters an input, readback signal to an approximation of a selected target waveform. The equalizer includes a plurality of serially connected analog filter sections having associated tap locations, analog multipliers which multiply the tap signals present at the tap locations by tap weight signals to generate product signals and a summer which sums the product signals to generate an equalized output signal. A self-synchronization circuit, responsive to the main tap of the equalizer, synchronizes the data recovery process used by the channel with the rate of the readback signals provided to the channel. The self-synchronization circuit includes peak detection circuitry which uses the main tap signal from the equalizer, as well as the differentiated main tap signal, to detect peaks in the readback signal indicative of magnetic transitions in order to generate timing error signals used to control the generation of a channel clock by a voltage controlled oscillator. A programmable delay allows fine adjustment of the phase of the channel clock to optimize data recovery of the channel, with the programmable delay being calibrated during receipt of sector preamble signals.