Averaging signals to improve signal interpretation

A signal processing apparatus, comprising:

• an input to receive a signal, wherein the signal from the input comprises an analog signal;
• an analog-to-digital converter (ADC) to convert the analog signal to a digital signal;
• a buffer responsive to the ADC to store the digital signal;
• a filter in communication with the ADC to produce a filtered digital signal based on the digital signal;
• a detector responsive to the filter to interpret the filtered digital signal as discrete values;
• an averaging circuit in communication with the buffer and the detector to cause interpretation, by the detector during a retry mode, of an averaged signal comprising a weighted average of one or more previous signals stored in the buffer and a current signal;
• and
• a control circuit that determines whether the discrete values are adequately indicated based on output of the detector, that initiates the retry mode when the discrete values are not adequately indicated, and that determines whether the discrete values are adequately indicated from the interpretation of the averaged signal in the retry mode,
• wherein the control circuit determines whether the discrete values are adequately indicated based on comparison of interpretations of the averaged signal and the current signal,
• wherein the averaging circuit determines the weighted average based on weights respectively associated with the one or more previous signals and the current signal, wherein the weights are based on respective signal quality measures, and wherein the signal quality measures are based on output of the detector.

A storage device, comprising:

• a storage medium;
• a head assembly operable to generate an analog read signal from the storage medium;
• an analog-to-digital converter (ADC) to convert the analog read signal to a digital read signal;
• a buffer that saves the digital read signal;
• a filter in communication with the ADC to produce a filtered digital read signal based on the digital read signal;
• a detector that interprets the filtered digital read signal as discrete values;
• an averaging circuit in communication with the buffer and the detector;
• a control circuit in communication with the averaging circuit to determine whether the discrete values are adequately indicated based on output of the detector, initiate a retry mode when the discrete values are not adequately indicated, cause interpretation by the detector in the retry mode of a new read signal comprising an average that is determined responsive to a group of signals, the group of signals comprising one or more previous signals stored in the buffer and a current read signal, and determine whether the discrete values are adequately indicated from the interpretation of the new read signal in the retry mode based on a measurement of differences between hard decisions indicated by the new signal and hard decisions indicated by the current signal;
• and
• an error correction circuit in communication with the detector and the averaging circuit to provide a signal quality metric that is based on output of the detector, wherein the control circuit uses the signal quality metric to selectively exclude a signal of the group of signals from the average.

A storage device, comprising:

• a storage medium;
• a head assembly operable to generate an analog read signal from the storage medium;
• an analog-to-digital converter (ADC) to convert the analog read signal to a digital read signal;
• a buffer that saves the digital read signal;
• a filter in communication with the ADC to produce a filtered digital read signal based on the digital read signal;
• a detector that interprets the filtered digital read signal as discrete values;
• an averaging circuit in communication with the buffer and the detector;
• and
• a control circuit in communication with the averaging circuit to determine whether the discrete values are adequately indicated based on output of the detector, initiate a retry mode when the discrete values are not adequately indicated, cause interpretation by the detector in the retry mode of an averaged read signal comprising a weighted average of one or more previous read signals stored in the buffer and a current read signal, and determine whether the discrete values are adequately indicated from the interpretation of the averaged signal in the retry mode,
• wherein the averaging circuit determines the weighted average based on weights respectively associated with the one or more previous signals and the current signal, wherein the weights are based on respective signal quality measures, and wherein the signal quality measures are based on output of the detector.

A method of reading data on a channel or media, the method comprising:

• interpreting an input signal as discrete values;
• deciding whether the discrete values have been adequately interpreted from the input signal;
• entering a retry mode in response to a decision that the discrete values have not been adequately interpreted from the input signal;
• obtaining, in the retry mode, second signals representing same data as the input signal;
• obtaining signal quality metrics corresponding to the second signals and the input signal;
• averaging, in the retry mode, multiple signals to produce an averaged signal to improve interpretation of the input signal, the multiple signals including at least two or more of the input signal and the second signals, wherein the averaging comprises using the signal quality metrics to selectively exclude a respective signal from the averaged signal;
• interpreting the averaged signal as new discrete values;
• and
• determining whether the new discrete values are adequately indicated.

A method of reading data on a channel or media, the method comprising:

• interpreting an input signal as discrete values;
• deciding whether the discrete values have been adequately interpreted from the input signal;
• entering a retry mode in response to a decision that the discrete values have not been adequately interpreted from the input signal;
• obtaining, in the retry mode, one or more second signals representing same data as the input signal;
• averaging, in the retry mode, multiple signals to improve interpretation of the input signal, wherein the averaging includes determining a weighted average based on weights, the input signal, and the one or more second signals to produce an averaged signal, wherein the weights correspond, respectively, to the input signal and the one or more second signals, wherein the weights are based on respective signal quality measures;
• interpreting the averaged signal as new discrete values;
• and
• determining whether the new discrete values are adequately indicated, wherein determining whether the new discrete values are adequately indicated comprises comparing interpretations of the averaged signal and of the one or more second signals.

A system comprising:

• means for storing data;
• and
• means for reading the data, said means for reading including:
• means for interpreting an input signal as discrete values;
• means for deciding whether the discrete values have been adequately interpreted from the input signal;
• means for entering a retry mode in response to a decision that the discrete values have not been adequately interpreted from the input signal;
• and
• means for averaging, in the retry mode, multiple read signals to produce an averaged signal to improve signal interpretation, the means for averaging including:
• means for obtaining second signals representing same data as the input signal, the multiple read signals including at least two or more of:
• the input signal and the second signals,
• means for obtaining signal quality metrics corresponding to the second signals and the input signal,
• means for using the signal quality metrics to selectively exclude a respective signal from the averaged signal,
• means for interpreting the averaged signal as new discrete values, and
• means for determining whether the new discrete values are adequately indicated;
• wherein the means for reading further includes error-detection means for controlling which read signals are averaged.

A system comprising:

• means for storing data;
• and
• means for reading the data, said means for reading including:
• means for interpreting an input signal as discrete values;
• means for deciding whether the discrete values have been adequately interpreted from the input signal;
• means for entering a retry mode in response to a decision that the discrete values have not been adequately interpreted from the input signal;
• and
• means for averaging, in the retry mode, multiple read signals to produce an averaged signal to improve signal interpretation, the means for averaging including:
• means for obtaining one or more second signals representing same data as the input signal,
• means for determining a weighted average based on weights, the input signal, and the one or more second signals to produce an averaged signal, wherein the weights correspond, respectively, to the input signal and the one or more second signals, wherein the weights are based on respective signal quality measures,
• means for interpreting the averaged signal as new discrete values, and
• means for determining whether the new discrete values are adequately indicated;
• wherein the means for reading further includes means for comparing an averaged read signal and a current read signal.

An article comprising:

• means for interpreting an input signal as discrete values;
• means for deciding whether the discrete values have been adequately interpreted from the input signal;
• means for entering a retry mode in response to a decision that the discrete values have not been adequately interpreted from the input signal;
• and
• means for averaging, in the retry mode, multiple read signals to produce an averaged signal to improve signal interpretation, the means for averaging including:
• means for obtaining second signals representing same data as the input signal, the multiple read signals including at least two or more of:
• the input signal and the second signals,
• means for obtaining signal quality metrics corresponding to the second signals and the input signal,
• means for using the signal quality metrics to selectively exclude a respective signal from the averaged signal,
• means for interpreting the averaged signal as new discrete values, and
• means for determining whether the discrete values are adequately indicated.

An article comprising:

• means for interpreting an input signal as discrete values;
• means for deciding whether the discrete values have been adequately interpreted from the input signal;
• means for entering a retry mode in response to a decision that the discrete values have not been adequately interpreted from the input signal;
• and
• means for averaging, in the retry mode, multiple read signals to produce an averaged signal to improve signal interpretation, the means for averaging including:
• means for obtaining one or more second signals representing same data as the input signal,
• means for determining a weighted average based on weights, the input signal, and the one or more second signals to produce an averaged signal, wherein the weights correspond, respectively, to the input signal and the one or more second signals, wherein the weights are based on respective signal quality measures,
• means for interpreting the averaged signal as new discrete values, and
• means for determining whether the new discrete values are adequately indicated, wherein the means for determining comprises means for comparing interpretations of the averaged signal and of the second signal.

An apparatus comprising:

• means for receiving a signal, wherein the signal comprises an analog signal;
• means for converting the analog signal to a digital signal;
• means for storing the digital signal;
• means for filtering the digital signal;
• means for interpreting the filtered digital signal as discrete values;
• retry-mode means for interpreting a new signal comprising an average that is determined responsive to a group of signals, the group of signals comprising one or more stored signals and a current signal;
• means for determining whether the discrete values are adequately indicated based on output of the means for interpreting, initiating the retry-mode means when the discrete values are not adequately indicated, and determining whether the discrete values are adequately indicated from the interpretation of the new signal by the retry-mode means based on a measurement of differences between hard decisions indicated by the new signal and hard decisions indicated by the current signal;
• means for providing a signal quality metric that governs which signals are averaged;
• and
• means for using the signal quality metric to selectively exclude the corresponding signal from the average.

An apparatus comprising:

• means for receiving a signal, wherein the signal comprises an analog signal;
• means for converting the analog signal to a digital signal;
• means for filtering the digital signal;
• means for interpreting the filtered digital signal as discrete values;
• retry-mode means for interpreting an averaged signal that is based on a weighted average of one or more stored signals and a current signal, wherein the weighted average is determined based on weights respectively associated with the one or more stored signals and the current signal, wherein the weights are based on respective signal quality measures;
• and
• means for determining whether the discrete values are adequately indicated based on output of the means for interpreting, initiating the retry-mode means when the discrete values are not adequately indicated, and determining whether the discrete values are adequately indicated from the interpretation of the averaged signal by the retry-mode means;
• wherein the means for determining comprises means for determining whether the discrete values are adequately indicated based on comparison of interpretations of the averaged signal and the current signal.

A non-transitory machine-readable medium embodying information indicative of instructions for causing one or more machines to perform operations for reading data on a channel or media, the operations comprising:

• interpreting an input signal as discrete values;
• deciding whether the discrete values have been adequately interpreted from the input signal;
• entering a retry mode in response to a decision that the discrete values have not been adequately interpreted from the input signal;
• and
• obtaining, in the retry mode, second signals representing same data as the input signal;
• obtaining signal quality metrics corresponding to the second signals and the input signal;
• averaging, in the retry mode, multiple signals to produce an averaged signal to improve interpretation of the input signal, the multiple signals including at least two or more of the input signal and the second signals, wherein the averaging comprises using the signal quality metrics to selectively exclude a respective signal from the averaged signal;
• interpreting the averaged signal as new discrete values;
• and
• determining whether the new discrete values are adequately indicated.

A non-transitory machine-readable medium embodying information indicative of instructions for causing one or more machines to perform operations for reading data on a channel or media, the operations comprising:

• interpreting an input signal as discrete values;
• deciding whether the discrete values have been adequately interpreted from the input signal;
• entering a retry mode in response to a decision that the discrete values have not been adequately interpreted from the input signal;
• obtaining, in the retry mode, one or more second signals representing same data as the input signal;
• averaging, in the retry mode, multiple signals to improve interpretation of the input signal, wherein the averaging includes determining a weighted average based on weights, the input signal, and the one or more second signals to produce an averaged signal and to improve signal interpretation, wherein the weights correspond, respectively, to the input signal and the one or more second signals, wherein the weights are based on respective signal quality measures;
• interpreting the averaged signal as new discrete values;
• and
• determining whether the new discrete values are adequately indicated based on the averaged signal;
• wherein determining whether the new discrete values are adequately indicated comprises comparing interpretations of the averaged signal and of the one or more second signals.