Systems and methods are disclosed for head delay calibration and tracking multi-sensor magnetic recording (MSMR) systems. In certain embodiments, an apparatus may comprise a first reader and a second reader configured to simultaneously read from a single track of a data storage medium, the first reader offset from the second reader such that the first reader and the second reader detect a same signal pattern offset in time. The apparatus may further comprise a circuit configured to determine a relative offset between the first reader and the second reader, including setting a fixed delay for a first signal from the first reader, setting a second delay for a second signal from the second reader, and adjusting the second delay to align the second signal to the first signal using a timing loop, with the first signal used as a reference signal.

An apparatus may include a circuit configured to generate, by an analog to digital converter (ADC), one or more ADC samples based on an input signal. The circuit may be further configured to generate a first estimated signal using a first channel pulse response estimation with a gain constraint based on the one or more ADC samples and generate a second estimated signal using a second channel pulse response estimation with a phase constraint based on the one or more ADC samples.

Systems and methods for a providing a chirped current profile with an undershoot for a channel preamplifier are described. A method for writing bits in a magnetic recording disc may include applying an overshoot to a write current which is supplied to a magnetic writer of the magnetic recording disc and applying an undershoot to the write current after the overshoot is applied to at least partially de-saturate the magnetic writer. The method may also include writing a bit to the magnetic recording disc with the magnetic writer using the supplied write current. In some examples, the application of a short negative pulse after an overshoot portion of the write current waveform is delivered to the head during a write operation that writes the bit to the magnetic recording disc.

A method for transmitting and/or receiving a potential aggressor audio signal includes a transmission and/or a reception of successive groups of data timed by a first clock signal within respective successive frames synchronized by a second clock signal. In the presence of a risk of interference of the potential aggressor audio signal with a different, potential victim, signal, during the transmission or reception of the potential aggressor audio signal, the frequency of the first clock signal is modified while keeping the frequency of the second clock signal unchanged.

An optical disc apparatus includes a synchronizer that generates a reproduction clock signal synchronized with a reproduction signal of information recorded in an optical disc medium, and generates a digital reproduction signal synchronized with the reproduction clock signal, an adaptive equalizer that generates a post-adaptive-equalization digital reproduction signal, and a maximum likelihood decoder that performs maximum likelihood decoding of the post-adaptive-equalization digital reproduction signal to generate a binary signal. The apparatus also includes an expected waveform generator that generates an expected waveform from the binary signal, a phase-advance waveform generator that generates a phase-advance waveform, a phase-delay waveform generator that generates a phase-delay waveform, and a metric detector that detects a phase error. In the optical disc apparatus, the synchronizer controls the phase of the digital reproduction signal using the phase error.

A system for compensating for heat induced transient phase shift in a heat assisted magnetic recording system. A heat assisted magnetic data recording system includes a near field thermal transducer that locally heats the media during writing. The thermal transducer, when activated, results in a change in size of a magnetic transition written to the magnetic media. This change in size of the thermal transition results in a transient phase shift of the data recorded on the magnetic media. The system includes circuitry for predetermining an anticipated amount of transient phase shift and adjusting a subsequent read signal to compensate for the known transient phase shift, thereby eliminating signal errors resulting from the transient phase shift.

Systems and methods for providing an output signal based at least in part upon an input signal and a clock signal in a manner in which jitter is avoided or diminished, including for example a digital-to-analog converter (DAC), are disclosed herein. In one example embodiment, such a system includes an output signal generating component, a first component having a first switch and a variable characteristic, and a plurality of second components each having a respective additional switch and a respective fixed characteristic. A value of the variable characteristic is set at least in part based upon input and clock signals so that, when the variable characteristic influences at least indirectly the generating of the output signal by the output signal generating component, the output signal attains a first level that at least indirectly depends upon a phase of the clock signal relative to the input signal.

The presently disclosed technology teaches integrating disc drive electronics into a transducer head. Decreased electrical transit times and data processing times can be achieved by placing the electronics on or within the transducer head because electrical connections may be made physically shorter than in conventional systems. The electronics may include one or more of a control system circuit, a write driver, and/or a data buffer. The control system circuit generates a modified clock signal that has a fixed relation to phase and frequency of a bit-detected reference signal that corresponds to positions of patterned bits on the disc. The write driver writes outgoing data bits received from an external connection to off-head electronics directly to the writer synchronized with the modified clock signal. The data buffer stores and converts digital data bits sent from the off-head electronics to an analog signal that is synchronized with the modified clock signal.

A computer-implemented method according to one embodiment includes performing anti-aliasing filtering on each of a plurality of signals, each signal having a frequency that is a different fraction of a frequency of a data read clock. An amplitude of each of the signals is measured after the anti-aliasing filtering. In response to the amplitudes of the signals being within a predefined range, anti-aliasing settings used during the anti-aliasing filtering are stored. In response to the amplitudes of the signals being outside the predefined range, the anti-aliasing settings are changed. A computer program product according to another embodiment includes a computer readable storage medium having program instructions embodied therewith. The computer readable storage medium is not a transitory signal per se. The program instructions are executable by a processing circuit to cause the processing circuit to perform the foregoing method.

A method for transmitting and/or receiving a potential aggressor audio signal includes a transmission and/or a reception of successive groups of data timed by a first clock signal within respective successive frames synchronized by a second clock signal. In the presence of a risk of interference of the potential aggressor audio signal with a different, potential victim, signal, during the transmission or reception of the potential aggressor audio signal, the frequency of the first clock signal is modified while keeping the frequency of the second clock signal unchanged.