Reproducing apparatus
First Claim
1. A reproducing apparatus comprising:
- first means for reproducing a signal of a run-length-limited code from a recording medium;
a transversal filter for subjecting the signal reproduced by the first means to partial-response waveform equalization to generate an equalization-resultant signal, the partial-response waveform equalization depending on tap coefficients;
second means for detecting whether or not the signal reproduced by the first means corresponds to a zero-cross point, and generating 0-point information in response to a result of said detecting;
a first delay circuit responsive to the 0-point information generated by the second means for outputting at least four successive samples of the 0-point information;
a second delay circuit responsive to the equalization-resultant signal generated by the transversal filter for outputting at least four successive samples of the equalization-resultant signal;
a temporary decision device for calculating a temporary decision value of the equalization-resultant signal on the basis of a PR mode signal, an RLL mode signal, the successive samples of the 0-point information which are outputted from the first delay circuit, and the successive samples of the equalization-resultant signal which are outputted from the second delay circuit, the PR mode signal representing a type of the partial-response waveform equalization, the RLL mode signal representing a type of the run-length-limited code;
third means for calculating a difference between the temporary decision value of the equalization-resultant signal and an actual value thereof, and generating an error signal in response to the calculated difference; and
fourth means for controlling the tap coefficients of the transversal filter in response to the error signal generated by the third means;
wherein the type of the partial-response waveform equalization is PR(a, b, b, b, a).
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Accused Products
Abstract
A transversal filter subjects a reproduced signal to partial-response waveform equalization responsive to tap coefficients to generate an equalization-resultant signal. There is generated 0-point information representing whether or not the reproduced signal corresponds to a zero-cross point. A temporary decision device calculates a temporary decision value of the equalization-resultant signal on the basis of a PR mode signal, an RLL mode signal, at least four successive samples of the 0-point information, and at least four successive samples of the equalization-resultant signal. Calculation is made as to a difference between the temporary decision value of the equalization-resultant signal and an actual value thereof. An error signal is generated in response to the calculated difference. The tap coefficients of the transversal filter are controlled in response to the generated error signal. The partial-response waveform equalization is PR(a, b, b, b, a).
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Citations
13 Claims
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1. A reproducing apparatus comprising:
-
first means for reproducing a signal of a run-length-limited code from a recording medium;
a transversal filter for subjecting the signal reproduced by the first means to partial-response waveform equalization to generate an equalization-resultant signal, the partial-response waveform equalization depending on tap coefficients;
second means for detecting whether or not the signal reproduced by the first means corresponds to a zero-cross point, and generating 0-point information in response to a result of said detecting;
a first delay circuit responsive to the 0-point information generated by the second means for outputting at least four successive samples of the 0-point information;
a second delay circuit responsive to the equalization-resultant signal generated by the transversal filter for outputting at least four successive samples of the equalization-resultant signal;
a temporary decision device for calculating a temporary decision value of the equalization-resultant signal on the basis of a PR mode signal, an RLL mode signal, the successive samples of the 0-point information which are outputted from the first delay circuit, and the successive samples of the equalization-resultant signal which are outputted from the second delay circuit, the PR mode signal representing a type of the partial-response waveform equalization, the RLL mode signal representing a type of the run-length-limited code;
third means for calculating a difference between the temporary decision value of the equalization-resultant signal and an actual value thereof, and generating an error signal in response to the calculated difference; and
fourth means for controlling the tap coefficients of the transversal filter in response to the error signal generated by the third means;
wherein the type of the partial-response waveform equalization is PR(a, b, b, b, a). - View Dependent Claims (3, 4, 5, 7, 8)
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2. A reproducing apparatus comprising:
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first means for reproducing a signal of a run-length-limited code from a recording medium;
a transversal filter for subjecting the signal reproduced by the first means to partial-response waveform equalization to generate an equalization-resultant signal, the partial-response waveform equalization depending on tap coefficients;
second means for detecting whether or not the equalization-resultant signal generated by the transversal filter corresponds to a zero-cross point, and generating 0-point information in response to a result of said detecting;
a first delay circuit responsive to the 0-point information generated by the second means for outputting at least four successive samples of the 0-point information;
a second delay circuit responsive to the equalization-resultant signal generated by the transversal filter for outputting at least four successive samples of the equalization-resultant signal;
a temporary decision device for calculating a temporary decision value of the equalization-resultant signal on the basis of a PR mode signal, an RLL mode signal, the successive samples of the 0-point information which are outputted from the first delay circuit, and the successive samples of the equalization-resultant signal which are outputted from the second delay circuit, the PR mode signal representing a type of the partial-response waveform equalization, the RLL mode signal representing a type of the run-length-limited code;
third means for calculating a difference between the temporary decision value of the equalization-resultant signal and an actual value thereof, and generating an error signal in response to the calculated difference; and
fourth means for controlling the tap coefficients of the transversal filter in response to the error signal generated by the third means;
wherein the type of the partial-response waveform equalization is PR(a, b, b, b, a). - View Dependent Claims (6)
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9. A recording and reproducing apparatus comprising:
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first means for generating a parity signal in response to an input signal, and adding the parity signal to the input signal to generate a parity-added signal;
a run length encoder for converting every “
m”
bits of the parity-added signal to “
n”
bits of a signal of a run-length-limited code, where “
m”
<
“
n”
;
second means for recording the signal of the run-length-limited code on a recording medium;
third means for reproducing the signal of the run-length-limited code from the recording medium;
an A/D converter for converting the signal reproduced by the third means into a digital reproduced signal;
a phase locked loop for re-sampling the digital reproduced signal at a re-sampling frequency to generate a re-sampling resultant signal, extracting a phase error from the digital reproduced signal, and controlling the re-sampling frequency in response to the extracted phase error;
fourth means for detecting whether or not the re-sampling resultant signal generated by the phase locked loop corresponds to a zero-cross point, and generating 0-point information in response to a result of said detecting;
an adaptive equalizer for subjecting the re-sampling resultant signal to waveform equalization in response to the 0-point information generated by the fourth means to generate an equalization-resultant signal;
a maximum likelihood decoder for subjecting the equalization-resultant signal to maximum likelihood decoding to generate a first decoding-resultant signal and first likelihood information relating to the first decoding-resultant signal;
a run length decoder for converting every “
n”
bits of the first decoding-resultant signal to “
m”
bits of a second decoding-resultant signal, and converting the first likelihood information to second likelihood information relating to the second decoding-resultant signal; and
fifth means for subjecting the second decoding-resultant signal generated by the run length decoder to error correction in response to a parity signal contained in the second decoding-resultant signal.
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10. A reproducing apparatus comprising:
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first means for reproducing a signal of a run-length-limited code from the recording medium;
an A/D converter for converting the signal reproduced by the first means into a digital reproduced signal;
a phase locked loop for re-sampling the digital reproduced signal at a re-sampling frequency to generate a re-sampling resultant signal, extracting a phase error from the digital reproduced signal, and controlling the re-sampling frequency in response to the extracted phase error;
second means for detecting whether or not the digital reproduced signal corresponds to a zero-cross point, and generating 0-point information in response to a result of said detecting;
an adaptive equalizer for subjecting the re-sampling resultant signal to waveform equalization in response to the 0-point information generated by the second means to generate an equalization-resultant signal;
a maximum likelihood decoder for subjecting the equalization-resultant signal to maximum likelihood decoding to generate a first decoding-resultant signal and first likelihood information relating to the first decoding-resultant signal;
a sync signal detector for detecting every sync signal in the first decoding-resultant signal;
third means for measuring a time interval between adjacent sync signals detected by the sync signal detector;
fourth means for determining whether or not the time interval measured by the third means is equal to a predetermined reference value;
fifth means for detecting at least one of (1) when an absolute value of the phase error exceeds a prescribed threshold value and (2) when the absolute value of the phase error is maximized, and generating slip point information representing a time position corresponding to said detecting;
sixth means for subjecting the first decoding-resultant signal and the first likelihood information to data length adjustment at the time position represented by the slip point information to generate a second decoding-resultant signal and second likelihood information in cases where the fourth means determines that the time interval measured by the third means is not equal to the predetermined reference value and the fifth means detects at least one of (1) when the absolute value of the phase error exceeds the prescribed threshold value and (2) when the absolute value of the phase error is maximized and; and
a run length decoder for converting every “
n”
bits of the second decoding-resultant signal to “
m”
bits of a third decoding-resultant signal, and converting the second likelihood information to third likelihood information relating to the third decoding-resultant signal, where “
m”
<
“
n”
. - View Dependent Claims (12)
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11. A reproducing apparatus comprising:
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first means for reproducing a signal of a run-length-limited code from the recording medium;
an A/D converter for converting the signal reproduced by the first means into a digital reproduced signal;
a phase locked loop for re-sampling the digital reproduced signal at a re-sampling frequency to generate a re-sampling resultant signal, extracting a phase error from the digital reproduced signal, and controlling the re-sampling frequency in response to the extracted phase error;
second means for detecting whether or not the re-sampling resultant signal corresponds to a zero-cross point, and generating 0-point information in response to a result of said detecting;
an adaptive equalizer for subjecting the re-sampling resultant signal to waveform equalization in response to the 0-point information generated by the second means to generate an equalization-resultant signal;
a maximum likelihood decoder for subjecting the equalization-resultant signal to maximum likelihood decoding to generate a first decoding-resultant signal and first likelihood information relating to the first decoding-resultant signal;
a sync signal detector for detecting every sync signal in the first decoding-resultant signal;
third means for measuring a time interval between adjacent sync signals detected by the sync signal detector;
fourth means for determining whether or not the time interval measured by the third means is equal to a predetermined reference value;
fifth means for detecting at least one of (1) when an absolute value of the phase error exceeds a prescribed threshold value and (2) when the absolute value of the phase error is maximized, and generating slip point information representing a time position corresponding to said detecting;
sixth means for subjecting the first decoding-resultant signal and the first likelihood information to data length adjustment at the time position represented by the slip point information to generate a second decoding-resultant signal and second likelihood information in cases where the fourth means determines that the time interval measured by the third means is not equal to the predetermined reference value and the fifth means detects at least one of (1) when the absolute value of the phase error exceeds the prescribed threshold value and (2) when the absolute value of the phase error is maximized and; and
a run length decoder for converting every “
n”
bits of the second decoding-resultant signal to “
m”
bits of a third decoding-resultant signal, and converting the second likelihood information to third likelihood information relating to the third decoding-resultant signal, where “
m”
<
“
n”
. - View Dependent Claims (13)
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Specification