"Flat analog" AFE coupled with an all digital architecture compensation read channel
First Claim
1. A system operable to read data from a magnetic storage media comprising:
- a read head, the read head operable to read data from the magnetic storage media and produce an analog signal;
a programmable gain amplifier operable to amplify the analog signal, such that the range of the amplified analog signal substantially matches a range of an analog to digital converter (ADC);
a continuous time anti-aliasing filter to substantially reduce both noise as well as signal energy above half a Baud signaling rate of the system, but otherwise not to substantially equalize or change an analog signals magnitude or phase below half the Baud signaling rate of the system;
an essentially static offset adjust module operable to center the amplified analog signal to a midscale of the ADC, where no high speed real time adjustments to an analog offset are made based on a detected or estimated transmitted signal, but rather adjustments are made to compensate for slow drifting of the analog offset due to temperature and voltage;
the ADC operable to sample the amplified analog signal and produce a digital signal;
a digital processing module operable to produce a compensated digital signal from the digital signal, such compensation comprising at least one function selected from the group comprising;
correcting analog read channel errors within the digital signal;
compensating for distortions caused by head type asymmetry; and
correcting for misequalization or mismatch in magnitude and/or phase between the digitized signal and a desired target for a sequence detector; and
a sequence detector operable to process the compensated digital signal and detect a bit sequence from the compensated digital signal.
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Accused Products
Abstract
Reading data from a magnetic storage media with an analog front end (AFE) coupled to an all digital read channel compensation architecture. A read head passes over magnetic storage media to produce an analog signal. The analog signal is amplified such that the range of the amplified analog signal substantial matches a range of the analog to digital converter (ADC) used to sample the analog signal. A baseline adjust is performed on the amplified analog signal to center the amplified analog signal to a midscale of the ADC. The amplified analog signal may be sampled where the sampling is data frequency locked by a data lock clock (DLC) tracking module. A digital signal may then be produced from the amplified analog signal where this signal is read channel compensated in the digital domain to produce a digital signal which is then processed with a sequence detector.
38 Citations
23 Claims
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1. A system operable to read data from a magnetic storage media comprising:
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a read head, the read head operable to read data from the magnetic storage media and produce an analog signal; a programmable gain amplifier operable to amplify the analog signal, such that the range of the amplified analog signal substantially matches a range of an analog to digital converter (ADC); a continuous time anti-aliasing filter to substantially reduce both noise as well as signal energy above half a Baud signaling rate of the system, but otherwise not to substantially equalize or change an analog signals magnitude or phase below half the Baud signaling rate of the system; an essentially static offset adjust module operable to center the amplified analog signal to a midscale of the ADC, where no high speed real time adjustments to an analog offset are made based on a detected or estimated transmitted signal, but rather adjustments are made to compensate for slow drifting of the analog offset due to temperature and voltage; the ADC operable to sample the amplified analog signal and produce a digital signal; a digital processing module operable to produce a compensated digital signal from the digital signal, such compensation comprising at least one function selected from the group comprising; correcting analog read channel errors within the digital signal; compensating for distortions caused by head type asymmetry; and correcting for misequalization or mismatch in magnitude and/or phase between the digitized signal and a desired target for a sequence detector; and a sequence detector operable to process the compensated digital signal and detect a bit sequence from the compensated digital signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A hard disk drive (HDD) controller operable to read data from a magnetic storage media comprising:
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a read head, the read head operable to read data from the magnetic storage media and produce an analog signal; a programmable gain amplifier operable to amplify the analog signal, such that the range of the amplified analog signal substantially matches a range of an analog to digital converter (ADC); a continuous time anti-aliasing filter to substantially reduce both noise as well as signal energy above half a Baud signaling rate of the system, but otherwise not to substantially equalize or change an analog signals magnitude or phase below half the Baud signaling rate of the system; an essentially static offset adjust module operable to center the amplified analog signal to a midscale of the ADC; the ADC operable to sample the amplified analog signal and produce a digital signal; a digital processing module operable to produce a compensated digital signal from the digital signal; and a sequence detector operable to process the compensated digital signal and detect a bit sequence from the compensated digital signal - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method to read data from magnetic storage media, comprising:
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passing a read head over a magnetic storage media to produce an analog signal; amplifying the analog signal such that a range of the amplified analog signal substantially matches a range of an analog to digital converter (ADC); performing a baseline adjust on the amplified analog signal to center the amplified analog signal to a midscale of the ADC; sampling the amplified analog signal with the ADC; producing a digital signal from the amplified analog signal; performing read channel compensation in a digital domain to produce a compensated digital signal from the digital signal; and detecting a bit sequence form the compensated digital signal. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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Specification