Abstract: An apparatus comprising a first circuit and a second circuit. The first circuit may be configured to generate a divided clock signal and a control signal in response to (i) an input clock signal and (ii) a configuration signal. The second circuit may be configured to generate an output clock signal in response to (i) the control signal and (ii) the divided clock signal. The second circuit may add a delay to one or more edges of the output clock signal by engaging one or more of a plurality of capacitances. A number of the capacitances engaged may be selected to reduce jitter on the output clock signal. The capacitances may be used each cycle to calibrate the output clock signal.

Abstract: An apparatus comprising a first circuit and a second circuit. The first circuit may be configured to generate a divided clock signal and a control signal in response to (i) an input clock signal and (ii) a configuration signal. The second circuit may be configured to generate an output clock signal in response to (i) the control signal and (ii) the divided clock signal. The second circuit may add a delay to one or more edges of the output clock signal by engaging one or more of a plurality of capacitances. A number of the capacitances engaged may be selected to reduce jitter on the output clock signal. The capacitances may be used each cycle to calibrate the output clock signal.

Abstract: An apparatus comprising a first circuit and a second circuit. The first circuit may be configured to generate a divided clock signal and a control signal in response to (i) an input clock signal and (ii) a configuration signal. The second circuit may be configured to generate an output clock signal in response to (i) the control signal and (ii) the divided clock signal. The second circuit may add a delay to one or more edges of the output clock signal by engaging one or more of a plurality of capacitances. A number of the capacitances engaged may be selected to reduce jitter on the output clock signal. The capacitances may be used each cycle to calibrate the output clock signal.

Abstract: According to one embodiment, a method for processing data includes directing first data through a first FIR gain module in response to a determination that the first data is being read from a magnetic tape medium in an asynchronous mode to control FIR gain of the first data. The method also includes directing second data through a second FIR gain module in response to a determination that the second data is being read from the magnetic tape medium in a synchronous mode to control FIR gain of the second data. Other systems and methods for processing data using dynamic gain control with adaptive equalizers are presented according to more embodiments.

Abstract: According to one embodiment, a magnetic tape drive includes a controller configured to direct first data through a first finite impulse response (FIR) gain module in response to a determination that the first data is being read from a magnetic tape medium in an asynchronous mode to control FIR gain of the first data. The controller is also configured to direct second data through a second FIR gain module in response to a determination that the second data is being read from the magnetic tape medium in a synchronous mode to control FIR gain of the second data. A FIR gain value of the second FIR gain module is automatically controlled. Other systems for dynamic gain control with adaptive equalizers are described according to more embodiments.

Abstract: In one embodiment, a system for processing data includes an equalizer having a finite impulse response (FIR) filter configured to process data read with a channel using servo coefficients to generate equalized data, and one or more low-pass filters configured to filter the equalized data to output filtered data. The one or more low-pass filters is configured to remove high frequency noise from the equalized data. A method for processing data in a read channel, in one embodiment, includes receiving data read from a magnetic tape using the read channel of a magnetic tape drive. A finite impulse response (FIR) filter is applied to the data by an equalizer using servo coefficients to output equalized data. One or more low-pass filters is applied to the equalized data to obtain filtered data, the one or more low-pass filters being configured to remove high frequency noise from the equalized data.

Abstract: According to one embodiment, a magnetic tape drive includes a controller configured to direct first data through a first finite impulse response (FIR) gain module in response to a determination that the first data is being read from a magnetic tape medium in an asynchronous mode to control FIR gain of the first data. The controller is also configured to direct second data through a second FIR gain module in response to a determination that the second data is being read from the magnetic tape medium in a synchronous mode to control FIR gain of the second data. A FIR gain value of the second FIR gain module is automatically controlled. Other systems for dynamic gain control with adaptive equalizers are described according to more embodiments.

Abstract: According to one embodiment, a method for processing data includes directing first data through a first FIR gain module in response to a determination that the first data is being read from a magnetic tape medium in an asynchronous mode to control FIR gain of the first data. The method also includes directing second data through a second FIR gain module in response to a determination that the second data is being read from the magnetic tape medium in a synchronous mode to control FIR gain of the second data. Other systems and methods for processing data using dynamic gain control with adaptive equalizers are presented according to more embodiments.

Abstract: In one embodiment, a system for processing data includes an equalizer having a finite impulse response (FIR) filter configured to process data read with a channel using servo coefficients to generate equalized data, and one or more low-pass filters configured to filter the equalized data to output filtered data. The one or more low-pass filters is configured to remove high frequency noise from the equalized data. A method for processing data in a read channel, in one embodiment, includes receiving data read from a magnetic tape using the read channel of a magnetic tape drive. A finite impulse response (FIR) filter is applied to the data by an equalizer using servo coefficients to output equalized data. One or more low-pass filters is applied to the equalized data to obtain filtered data, the one or more low-pass filters being configured to remove high frequency noise from the equalized data.

Abstract: According to one embodiment, a system for processing data includes a controller configured to: receive data read from a magnetic storage medium, apply a finite impulse response (FIR) filter to the data to obtain equalized data, and direct the equalized data through either a first FIR gain module or a second FIR gain module to control FIR gain of the equalized data, wherein the first FIR gain module is utilized when reading data in an asynchronous mode, and wherein the second FIR gain module is utilized when reading data in a synchronous mode and a FIR gain value of the second FIR gain module is automatically controlled. Other systems and methods for processing data using dynamic gain control with adaptive equalizers are presented according to more embodiments.

Abstract: According to one embodiment, a system for processing data includes a controller configured to: receive data read from a magnetic storage medium, apply a finite impulse response (FIR) filter to the data to obtain equalized data, and direct the equalized data through either a first FIR gain module or a second FIR gain module to control FIR gain of the equalized data, wherein the first FIR gain module is utilized when reading data in an asynchronous mode, and wherein the second FIR gain module is utilized when reading data in a synchronous mode and a FIR gain value of the second FIR gain module is automatically controlled. Other systems and methods for processing data using dynamic gain control with adaptive equalizers are presented according to more embodiments.

Abstract: In one embodiment, a method includes passing a signal through an adaptive noise whitening filter, wherein one or more noise whitening coefficients used in the noise whitening filter are updated using a noise whitening filter coefficient updater, wherein the noise whitening filter is configured to process the signal according to a transfer polynomial: W(D)=1?(p1D+ . . . +p??D??), where p1 . . . p?? are noise whitening coefficients, where a tape channel is characterized by a transfer polynomial F(D)=1+f1D+ . . . +fLDL where D is delay corresponding to bit duration, with 2L being a number of states of the tape channel, wherein a soft detector has a total of 2L+? states, the noise whitening filter comprises 2?? states, ?? is greater than ?, L represents a memory length of the tape channel, and ? represents a memory length of the noise whitening filter.

Abstract: In accordance with one embodiment, a computer program product includes a computer readable storage medium having computer readable program code that is readable and/or executable by a processor to: receive a signal including precoded data read from a magnetic tape medium and pass the signal through a soft detector to calculator first soft information about each bit of the signal and to provide adaptive compensation for the precoded data, send the first soft information to a soft decoder, pass the signal through the soft decoder to calculate second soft information about each bit the signal, and send the second soft information to the soft detector, wherein the precoded data is passed through at least one precoder prior to being written to the magnetic tape medium via a precoder that applies 1/(1?D2) to bits of data, where D is delay corresponding to bit duration

Abstract: In one embodiment, a method includes passing a signal through a noise whitening filter, passing the signal through a soft detector to calculate first soft information, passing the signal through the soft decoder to calculate second soft information based on the first soft information, and sending the second soft information to the soft detector, wherein the noise whitening filter is configured to process the signal according to the following transfer polynomial: W(D)=1?(p1D+ . . . p1D?), where p1 . . . p? are noise whitening coefficients, D is delay corresponding to bit duration, and a transfer polynomial of the tape channel is F(D)=1+f1D+ . . . +fLDL, wherein L represents a memory length of the tape channel, and wherein ? represents a memory length of the noise whitening filter. Other methods, systems, and computer program products are described in more embodiments.

Abstract: According to one embodiment, a system for processing data includes an equalizer configured to use servo coefficients for processing servo data and data coefficients for processing non-servo data, wherein the equalizer includes a finite impulse response (FIR) filter configured to process data read with a magnetic tape channel using the servo coefficients to generate equalized data, one or more low-pass filters with aggressive frequency characteristics configured to filter the equalized data to output filtered data, the one or more low-pass filters with aggressive frequency characteristics being configured to remove high frequency noise from the equalized data, a peak detector configured to process peaks in a waveform of the filtered data, and at least one servo pattern detector configured to detect a servo pattern in the filtered data. Other systems and methods for processing data are described in more embodiments.

Abstract: In one embodiment, a method includes passing a signal through an adaptive noise whitening filter, wherein one or more noise whitening coefficients used in the noise whitening filter are updated using a noise whitening filter coefficient updater, wherein the noise whitening filter is configured to process the signal according to a transfer polynomial: W(D)=1?(p1D+ . . . p??·D??), where p1 . . . p?? are noise whitening coefficients, where a tape channel is characterized by a transfer polynomial F(D)=1+f1D+ . . . +fLDL where D is delay corresponding to bit duration, with 2L being a number of states of the tape channel, wherein a soft detector has a total of 2L+? states, the noise whitening filter comprises 2?? states, ?? is greater than ?, L represents a memory length of the tape channel, and ? represents a memory length of the noise whitening filter.

Abstract: In one embodiment, a method includes passing a signal through a noise whitening filter, passing the signal through a soft detector to calculate first soft information, passing the signal through the soft decoder to calculate second soft information based on the first soft information, and sending the second soft information to the soft detector, wherein the noise whitening filter is configured to process the signal according to the following transfer polynomial: W(D)=1?(p1D+ . . . . p1D?), where p1 . . . p? are noise whitening coefficients, D is delay corresponding to bit duration, and a transfer polynomial of the tape channel is F(D)=1+f1D+ . . . +fLDL, wherein L represents a memory length of the tape channel, and wherein ? represents a memory length of the noise whitening filter. Other methods, systems, and computer program products are described in more embodiments.

Abstract: In accordance with one embodiment, a computer program product includes a computer readable storage medium having computer readable program code that is readable and/or executable by a processor to: receive a signal including precoded data read from a magnetic tape medium and pass the signal through a soft detector to calculate first soft information about each bit of the signal and to provide adaptive compensation for the precoded data, send the first soft information to a soft decoder, pass the signal through the soft decoder to calculate second soft information about each bit of the signal, and send the second soft information to the soft detector, wherein the precoded data is passed through at least one precoder prior to being written to the magnetic tape medium via a precoder that applies 1/(1?D2) to bits of data, where D is delay corresponding to bit duration.

Abstract: In accordance with one embodiment, a data storage system includes a tape channel for reading precoded data from a magnetic tape medium to produce a signal, a soft detector adapted for calculating first soft information about each bit of the signal and sending the first soft information to a soft decoder, and the soft decoder positioned subsequent to the soft detector, the soft decoder being adapted for calculating second soft information about each bit of the signal and sending the second soft information to the soft detector, wherein the precoded data includes a characteristic of being passed through at least one precoder prior to being written to the magnetic tape medium, and wherein the soft detector provides automatic compensation for the precoded data. Other systems, methods, and computer program products for reading data using an adaptive soft-output detector are described according to more embodiments.

Abstract: In one embodiment, a data storage system includes a tape channel for reading data from a magnetic tape medium to produce a signal, a noise whitening filter positioned subsequent to the tape channel adapted for receiving the signal, wherein the noise whitening filter is adapted for minimizing variance of its output signal, a soft detector adapted for receiving output from the noise whitening filter, the soft detector adapted for calculating first soft information about each bit of the signal and sending the first soft information to a soft decoder, and the soft decoder positioned subsequent to the soft detector, the soft decoder being adapted for calculating second soft information about each bit of the signal and sending the second soft information to the soft detector. Other systems, methods, and computer program products are described according to more embodiments.