Apparatus and method for measuring a characteristic pulse width for a data channel in a data handling device
First Claim
1. An apparatus for measuring a characteristic pulse width for a data channel of a data handling device, said apparatus comprising:
- a comparator for receiving a rectified input signal, comparing said rectified input signal to a reference signal representative of a predetermined reference voltage, and generating a pulse signal corresponding to a portion of said rectified input signal having a signal level in excess of said predetermined reference voltage, with said rectified input signal corresponding to a predetermined reference datum detected through said data channel;
a low pass filter, in communication with said comparator, for low-pass filtering said pulse signal and generating therefrom an average value signal representative of an average value of said pulse signal; and
an analog-to-digital converter, in communication with said low pass filter, for converting said average value signal into a digital signal corresponding to said average value, whereby a digital processor can generate from said digital signal a pulse width value representative of said characteristic pulse width.
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Abstract
An apparatus and method for measuring a characteristic pulse width of a data channel for a data handling device, with particular application to an HDD having an automatic gain control amplifier for amplifying a signal reproduced by a magnetic head, a filter/equalizer circuit for removing a noise component from an output signal from the automatic gain control amplifier and wave-shaping the resultant signal, a rectifier for rectifying an output signal from the filter/equalizer circuit, a first low pass filter for low pass filtering an output signal from the rectifier to detect an average value thereof, and a charge pump and a capacitor for cooperating to control an amplification gain of the automatic gain control amplifier in response to an output signal from the first low pass filter. The apparatus comprises a comparator for comparing the output signal from the rectifier with a predetermined reference voltage and generating a pulse signal in accordance with the compared result, a second low pass filter for low pass filtering an output signal from the comparator to detect an average value thereof, and an analog/digital converter for converting an output signal from the second low pass filter into a digital signal. According to the present invention, the apparatus can measure a PW50 value directly in the HDD, thereby providing for implementation of an improved AZO method.
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Citations
35 Claims
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1. An apparatus for measuring a characteristic pulse width for a data channel of a data handling device, said apparatus comprising:
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a comparator for receiving a rectified input signal, comparing said rectified input signal to a reference signal representative of a predetermined reference voltage, and generating a pulse signal corresponding to a portion of said rectified input signal having a signal level in excess of said predetermined reference voltage, with said rectified input signal corresponding to a predetermined reference datum detected through said data channel; a low pass filter, in communication with said comparator, for low-pass filtering said pulse signal and generating therefrom an average value signal representative of an average value of said pulse signal; and an analog-to-digital converter, in communication with said low pass filter, for converting said average value signal into a digital signal corresponding to said average value, whereby a digital processor can generate from said digital signal a pulse width value representative of said characteristic pulse width. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for measuring a characteristic pulse width for a data channel of a data handling device, said apparatus comprising:
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reference voltage means for generating a reference voltage signal having an amplitude corresponding to a predetermined fraction of an amplitude of a rectified input signal, with said rectified input signal corresponding to a predetermined reference datum detected through said data channel; a first comparator, in communication with said reference voltage means, for receiving said rectified input signal, comparing said rectified input signal to said reference voltage signal, and generating a pulse signal corresponding to a portion of said rectified input signal having a signal level in excess of a signal level of said reference voltage signal; and a low pass filter, in communication with said first comparator, for low-pass filtering said pulse signal and generating therefrom an average value signal representative of an average value of said pulse signal. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method of measuring a characteristic pulse width for a data channel of a data handling device, said method comprising the steps of:
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comparing a rectified input signal to an analog voltage signal and generating a pulse signal corresponding to a portion of said rectified input signal having a signal level in excess of a signal level of said analog voltage signal, with said rectified input signal corresponding to a predetermined reference datum detected through said data channel; generating an average value signal by low-pass filtering said pulse signal, with said average value signal representative of an average of said pulse signal; and converting said average value signal into a corresponding digital signal, whereby a digital processor can generate from said digital signal a pulse width value representative of said characteristic pulse width. - View Dependent Claims (18)
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19. An apparatus for measuring a characteristic pulse width for a data channel of a data handling device, said apparatus comprising:
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comparator means for receiving a rectified input signal, comparing said rectified input signal to a reference signal, and generating a pulse signal; low pass filter means connected to said comparator means for low-pass filtering said pulse signal and generating therefrom an average value of said pulse signal; and analog-to-digital converter means connected to said low pass filter means for converting said average value of said value signal into a digital signal, whereby a digital processor can generate from said digital signal a pulse width value representative of said characteristic pulse width. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26)
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27. An apparatus for measuring a characteristic pulse width for a data channel of a data handling device, said apparatus comprising:
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reference voltage means for generating a reference voltage signal having an amplitude corresponding to a predetermined reference datum detected through said data channel; first comparator means connected to said reference voltage means for receiving said rectified input signal, comparing said rectified input signal to said reference voltage signal, and generating a pulse signal corresponding to a portion of said rectified input signal; and low pass filter means connected to said first comparator means for low-pass filtering said pulse signal to generate an average value of said pulse signal. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34)
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35. A method of measuring a characteristic pulse width for a data channel of a data handling device, said method comprising the steps of:
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comparing a rectified input signal to a reference voltage signal having an amplitude corresponding to a predetermined fraction of an amplitude of said rectified input signal and generating a pulse signal corresponding to a portion of said rectified input signal having a signal level in excess of a signal level of said reference voltage signal, with said rectified input signal corresponding to a predetermined reference datum detected through said data channel; generating an average value signal by low-pass filtering said pulse signal, with said average value signal representative of an average value of said pulse signal; and converting said average value signal into a corresponding digital signal.
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Specification