JPH09282808A - Data processing apparatus and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain optimum reproduced data, even when a digital signal has changed rapidly, without increase of redundancy of the digital signal. SOLUTION: The data detectors 10, 20 and 30 respectively generate the detected data A, B and C depending on the amplitude detection system, peak detection system and viterbi decoding system. Reliability of the detected data A, b and c is respectively evaluated by reliability evaluators 14, 24 and 34 and are then compared by a comparator 40. Memories 13, 23 and 33 accumulate the reproduced data for the period as long as the time required by reliability evaluation of the reproduced data and then outputs the reproduced data to a selector 50. The selector 50 selects the reproduced data having the highest reliability and then detects such data depending on the comparison result by the comparator 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data processing device and a data processing method, and more particularly to decoding a plurality of data under a plurality of mutually different conditions and selecting the most reliable decoded data among them. And a data processing method.

[0002]

2. Description of the Related Art When decoding and reproducing a digital signal reproduced from a recording medium such as an optical disk, a magnetic disk, or a magnetic tape, or a digital signal transmitted using a communication transmission line as a medium, due to band limitation or noise mixing, The data error rate may deteriorate.

Therefore, in the conventional data processing apparatus, in order to secure the reliability of the detection data obtained by reproducing the digital signal, the type of medium on which the digital signal is recorded or transmitted and the medium recorded on the medium are recorded. According to the characteristics of the existing digital signal, for example, the optimum data detection method and the characteristics of the waveform equalizer are selected and set from the amplitude detection method, the peak detection method, the Viterbi decoding method, and the like.

However, even when the optimum characteristics are set as described above, when reproducing digital signals recorded on different media, unevenness in the media, changes over time in the apparatus, quality variations, disturbances, etc. In some cases, the characteristics may deviate from the optimum state.

In order to solve the above problems, for example, as shown in FIG. 5, a digital signal output from a digital signal input unit 71 is equalized by an equalizer 72 and then a peak detector 74 detects the peak. When the output of the peak detector 74 is further processed by the digital signal processor 75, the output of the equalizer 72 is evaluated by the evaluator 73, and the output of the equalizer 72 is preset. It is also proposed to compare with a predetermined reference value and adaptively change the characteristic of the equalizer 72 according to the comparison result.

[0006]

However, even when the characteristics of the equalizer 72 described above are automatically controlled, the following problems occur.

That is, in the method of adjusting the waveform equalization characteristic by inserting a signal for equalizer adjustment into a digital signal for automatic equalization and referring to the signal for equalizer adjustment. However, there is a problem that the redundancy of digital signals increases.

Further, in the method in which the equalization error of the equalized signal is detected and the waveform equalization characteristic is feedback-controlled so as to suppress the equalization error, the waveform is responded to a sudden change of the equalized reproduction signal. There is a problem in that it is difficult to quickly optimize the equalization characteristics, and the parameters used for waveform equalization may diverge, and appropriate waveform equalization processing may not be performed.

Further, depending on the apparatus, it may be better to switch the data detection method itself to a different type of method, and there is a problem that automatic equalization is not sufficient.

The present invention has been made in view of the above circumstances, and suppresses an increase in the redundancy of a digital signal recorded on a medium, and even when the input digital signal changes abruptly, This makes it possible to quickly obtain the optimum detection data.

[0011]

According to a first aspect of the present invention, there is provided a data processing device which decodes an input digital signal according to a plurality of different conditions and a plurality of decoding conditions. Of the decrypted data,
It is characterized by comprising an evaluating means for evaluating each reliability and a selecting means for selecting one decoded data from a plurality of decoded data corresponding to the evaluation result of the evaluating means.

According to a fifth aspect of the data processing method, the input digital signal is decoded under a plurality of mutually different conditions, and the reliability of each of the plurality of decoded data decoded under a plurality of mutually different conditions is verified. It is characterized in that evaluation is performed and one piece of decoded data is selected from a plurality of pieces of decoded data corresponding to the evaluation result.

In the data processing device according to the first aspect of the present invention, the decoding means decodes the input digital signal under a plurality of different conditions, and the evaluation means decodes under a plurality of different conditions. The reliability of each of the decrypted data is evaluated. Then, the selection means selects one piece of decoded data from the plurality of pieces of decoded data, corresponding to the evaluation result of the evaluation means.

According to a fifth aspect of the data processing method, one of the plurality of pieces of decoded data corresponding to each reliability evaluation of the plurality of pieces of decoded data decoded under a plurality of mutually different conditions is evaluated. Decrypted data is selected.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of a data processing apparatus to which the present invention is applied. In the data processing apparatus of this embodiment, the digital signal input device 1
However, for example, it reproduces a digital signal recorded on a recording medium such as an optical disk, a magnetic disk, a magnetic tape, or receives a digital signal transmitted via a predetermined transmission path. The digital signal thus input is supplied to the data detectors 10, 20 and 30.

The data detector 10 includes an equalizer 1 therein.
1 and an amplitude detection type detector 12, and the digital signal supplied from the digital signal input device 1 is input to the equalizer 11. The equalizer 11 has
The input signal is subjected to waveform equalization processing adapted to the amplitude detection type detector 12 provided in the subsequent stage, and the output thereof is supplied to the amplitude detection type detector 12.

The amplitude detection type detector 12 detects the output signal of the equalizer 11 by the amplitude detection method and supplies the detection data A to the memory 13. The error correction circuit 15 uses the detection data A stored in the memory 13.
Error is corrected using an ECC code (error detection and correction code) included in the data and output to the selector 50.

The reliability evaluator 14 is supplied with a value having a correlation with the error rate of the detection data A from the error correction circuit 15, converts it into an evaluation value a, and supplies it to the comparator 40. ing.

The data detector 20 includes an equalizer 2 inside.
1 and a peak detection type detector 22 are provided, and the signal supplied from the digital signal input device 1 is input to the equalizer 21. The equalizer 21 uses the input signal to detect the peak detection type detector 2 provided in the subsequent stage.
The waveform equalization processing adapted to No. 2 is applied, and the output is supplied to the peak detection type detector 22.

The peak detection type detector 22 detects the output signal of the equalizer 21 by the peak detection method and supplies the detection data B to the memory 23.
The error correction circuit 25 corrects an error in the detection data B stored in the memory 23 using an ECC code included in the data and outputs the error to the selector 50.

The reliability evaluator 24 receives a value having a correlation with the error rate of the detection data B from the error correction circuit 25,
The value is converted into an evaluation value b and supplied to the comparator 40.

The data detector 30 has an equalizer 3 inside.
1 and a Viterbi decoder 32, and the signal supplied from the digital signal input device 1 is input to the equalizer 31. The equalizer 31 subjects the input signal to waveform equalization processing adapted to the Viterbi decoder 32 provided in the subsequent stage, and supplies the output to the Viterbi decoder 32.

The Viterbi decoder 32 performs Viterbi decoding processing on the output signal of the equalizer 31 to generate detection data C, and supplies the detection data C to the memory 33. The error correction circuit 35 corrects an error in the detection data C stored in the memory 33 using an ECC code included in the data and outputs the error to the selector 50.

The reliability evaluator 34 receives a value having a correlation with the error rate of the detected data C from the error correction circuit 35,
The value is converted into an evaluation value c and supplied to the comparator 40.

The reliability evaluators 14, 24 and 34
The evaluation values detected by are the same kind of evaluation values.

The comparator 40 compares the input evaluation values a, b and c to determine which of the detection data A to C has the highest reliability of detection data,
The judgment result is input to the selector 50.

The selector 50 selects the most reliable detection data among the detection data A, B and C supplied from the memories 13, 23 and 33 based on the judgment result of the comparator 40. Then, the selected detection data is supplied to the digital signal processor 60.

The digital signal processor 60 is a selector 50.
The detection data supplied from is processed and output to a circuit (not shown).

Next, the operation of the data processing apparatus of this embodiment will be described.

The digital signal input device 1 reproduces a digital signal recorded on a recording medium, for example. The reproduced signal reproduced there is equalized by the equalizer 1 in the data detector 10.
1, an equalizer 21 in the data detector 20, and an equalizer 31 in the data detector 30.

The equalizers 11, 21 and 31 receive the waveform equalization processing adapted to the amplitude detection type detector 12, the peak detection type detector 22 and the Viterbi decoder 32, which are provided in the subsequent stages, respectively. A signal is applied, and the output is applied to the amplitude detection type detector 12 and the peak detection type detector 2, respectively.
2 and Viterbi decoder 32.

The amplitude detection type detector 12 detects the signal supplied from the equalizer 11 by the amplitude detection method. The amplitude detection method detects the amplitude of a signal input at a predetermined timing (the signal value at that timing), and outputs "1" as detection data when the detected value is higher than a predetermined reference level. When the detected value is smaller than the reference level, "0" is output as the detection data. The detection data A generated by the amplitude detection type detector 12 is supplied to the memory 13.

The peak detection type detector 22 detects the signal supplied from the equalizer 21 by the peak detection method. The peak detection method differentiates an input signal, reads the differentiated signal in synchronization with a predetermined clock, and when the read value is a value representing a peak point (change point of signal level), it is detected as detection data. This is a method of outputting "1" and outputting "0" as detection data when the read value is a value other than the peak point. Peak detection type detector 2
The detection data B generated by 2 is supplied to the memory 23.

The Viterbi decoder 32 detects the signal supplied from the equalizer 31 using the Viterbi decoding method. The Viterbi decoding method uses the repetition characteristic of a convolutional code to estimate a code sequence that is closest to the transmission code (that is, maximizes the likelihood) with respect to the reception sequence, and uses the estimated code sequence as the basis. This is a method for decoding the detection data. The detection data C decoded by the Viterbi decoder 32 is stored in the memory 3
3 is supplied.

The reliability evaluators 14, 24 and 34 detect values having correlations with the error rates of the detection data A, B and C as evaluation values a, b and c, respectively, and the evaluation values are compared by the comparator 40. Supply to.

The comparator 40 compares the evaluation values a, b and c supplied from the reliability evaluators 14, 24 and 34 to determine the reliability of any of the detection data A, B and C. Is determined to be the highest, and the determination result is output to the selector 50.

Usually, the reliability evaluators 14, 24 and 34
A predetermined time is required to detect the evaluation value of (i.e., a delay time occurs due to the evaluation value detection). Therefore, when the comparison result of the comparator 40 is supplied to the selector 50, the memories 13, 23 and 33 are at least based on the evaluation value detection so that the detection data A, B and C are supplied to the selector 50. The detection data A, B and C are accumulated and the timing is adjusted for the delay time that occurs.

The selector 50 selects the most reliable detection data among the detection data A, B and C supplied from the memories 13, 23 and 33 according to the judgment result of the comparator 40, and selects the detection data. The detected data thus obtained is supplied to the digital signal processor 60.

For example, when noise is concentrated in the low frequency range of the signals input to the data detectors 10, 20 and 30, the comparator 40 detects the detection data A generated by the amplitude detection type detector 12. It is determined that the reliability is highest, and the determination result is supplied to the selector 50. Therefore, in this case,
The selector 50 selects the detection data A and supplies it to the digital signal processor 60.

Further, for example, each data detector 10, 20
When noise is concentrated in the high frequency range of the signals input to the input terminals 30 and 30, or the noise is flat, the comparator 40 determines that the detection data C generated by the Viterbi decoder 32 has the highest reliability. It is determined and the determination result is supplied to the selector 50. Therefore, in this case, the selector 50 selects the detection data C and supplies it to the digital signal processor 60.

In this embodiment, a plurality of detection data A, B and C are generated by a plurality of detection methods (amplitude detection method, peak detection method, Viterbi decoding method), and the most reliable detection data among them is generated. Is output. Therefore, even when a signal having a characteristic change that cannot be handled by the automatic equalizer is reproduced, the most suitable detection data can be output,
Since it is not necessary to add adjustment data in order to realize automatic equalization, it is possible to prevent an increase in redundancy of recording signals.

Further, in the present embodiment, since the detection data is delayed at least by the time for detecting the reliability evaluation value, the optimum value is obtained even when the characteristics of the reproduced signal change as a result. It is possible to promptly output various detection data.

Although three data detectors are provided in this embodiment, more data detectors may be provided.

FIG. 2 is a block diagram showing the configuration of another embodiment of the data processing apparatus to which the present invention is applied. The configuration of the data processing device of this embodiment is basically the same as the configuration of the data processing device shown in FIG. 1, except for the following points.

That is, in the data processor of this embodiment, unlike the case shown in FIG. 1, the reliability evaluator 14,
The outputs of the equalizers 11, 21 and 31 are input to 24 and 34, respectively, and the reliability evaluators 14, 24 and 34 detect the equalization error of the equalizer outputs input to each. Has been done.

That is, the reliability evaluators 14, 24 and 34 detect the equalization error of the signals (equalizer output) supplied from the equalizers 11, 21 and 31, respectively, and detect the detected equalization error. Are supplied to the comparator 40 as evaluation values (evaluation values a, b and c).

The comparator 40 determines which equalization error is the smallest among the evaluation values (equalization errors) a, b and c supplied from the reliability evaluators 14, 24 and 34. Whether the reliability of the equalizer output is high), and the determination result is output to the selector 50.

The selector 50 has the smallest equalization error of the equalizer output among the detection data A, B and C respectively supplied from the memories 13, 23 and 33 according to the judgment result of the comparator 40. Is output to the digital signal processor 60.

In the present embodiment, a plurality of equalizers having different frequency characteristics are provided, and the equalizer output is generated based on the equalizer output having the smallest equalization error among the equalizer outputs. The detection data is output.
Therefore, since it is not necessary to perform the feedback control of the equalizer 72 as shown in FIG. 5, the detection data can be quickly and accurately reproduced.

FIG. 3 is a block diagram showing the configuration of still another embodiment of the data processing device to which the present invention is applied. The configuration of the data processing device of this embodiment is basically the same as the configuration of the data processing device shown in FIG. 1, except for the following points.

That is, in the data processing apparatus of this embodiment, the reproduction signal output from the digital signal input device 1 is supplied to one equalizer 100, and the equalizer 100 is supplied.
Is supplied to the amplitude detection type detector 12, the peak detection type detector 22, and the Viterbi decoder 32. In addition,
Other configurations and operations are similar to those of the data reproducing apparatus shown in FIG.

The data processing apparatus of this embodiment is provided with only one equalizer for equalizing the waveform of the reproduced signal. Therefore, in this embodiment, a low-cost data processing device can be obtained as compared with the data processing devices shown in FIGS.

In the above embodiment, one of the outputs of the three types of detectors is selected. For example, when an error is detected in the embodiment of FIG. 1, the process shown in the flow chart of FIG. To the comparator 40 and the selector 50
By doing so, it is possible to obtain data with fewer errors.

That is, for example, first in step S1, it is determined whether or not there is an erroneous symbol by the reliability evaluator 1.
It judges from the output of 4, 24 and 34. If no erroneous symbol exists, no special processing is done. When it is determined in step S1 that there is an erroneous symbol, the process proceeds to step S2, and it is determined whether or not the number of erroneous symbols is equal to or less than a predetermined reference value set in advance.

If error correction is performed up to the maximum correctable number of errors in the error correction code, the probability of error correction increases.
In order to avoid this, the number of error corrections can be limited to a predetermined reference value or less in the error correction processing. In step S2, it is determined whether the number of erroneous symbols is less than or equal to the reference value. If the number of erroneous symbols is less than or equal to the reference value, the process proceeds to step S3, and the erroneous symbols are corrected.

If it is determined in step S2 that the number of erroneous symbols is larger than the reference value, the correction will increase the probability of erroneous correction. Therefore, in this case, the process proceeds to step S4, and it is determined whether or not another data detector outputs a correct (non-erroneous) symbol.

For example, when the reliability evaluator 14 detects an error for a predetermined symbol, the reliability evaluator 24
, Determines whether the corresponding symbol in the data detector 20 is not erroneous. If any of the other reliability evaluators determines that the corresponding symbol is erroneous, the error is eventually uncorrectable, so that no particular process is performed and the process returns to step S1.

If it is determined in step S4 that the other data detector is outputting the correct symbol, the process proceeds to step S5, and the correct symbol output by the data detector is extracted to determine that it is an erroneous symbol. Replace it
Synthesize new data.

Next, in step S6, it is determined whether or not the new data combined in step S5 still contains an erroneous symbol. When it is determined that the erroneous symbol is still included, the process proceeds to step S8, and it is determined whether or not the number of the erroneous symbol is equal to or less than the reference value. If the number of erroneous symbols is equal to or smaller than the reference value, it is unlikely that erroneous correction will be performed even if the error is corrected. Therefore, the process proceeds to step S3, and the erroneous symbol is corrected.

On the other hand, if it is determined in step S8 that the number of erroneous symbols is larger than the reference value,
After all, since correct data cannot be obtained, no particular process is performed and the process returns to step S1.

If it is determined in step S6 that the combined data does not include an erroneous symbol, the process proceeds to step S7, and the data composed of the combined symbol is output as new decoded data.

By doing so, even if there is an error equal to or larger than the reference value when the detection is performed by one data detector, the error can be corrected.

[0064]

As described above, according to the data processing apparatus and the data processing method of the present invention, the reliability of each of a plurality of decoded data is evaluated, and 1 is calculated based on the evaluation result.
Since one decoded data is selected, even when the digital signal changes abruptly, the optimum data can be obtained at high speed without increasing the redundancy of the digital signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a data processing device to which the present invention is applied.

FIG. 2 is a block diagram showing the configuration of another embodiment of the data processing device to which the present invention is applied.

FIG. 3 is a block diagram showing the configuration of still another embodiment of the data processing device to which the present invention is applied.

FIG. 4 is a flowchart illustrating the operation of the embodiment of FIG.

FIG. 5 is a block diagram showing a configuration of a conventional data processing device.

[Explanation of symbols]

1 digital signal input device, 10 data detector,
11 equalizer, 12 amplitude detection type detector, 13 memory, 14 reliability evaluator, 20 data detector,
21 equalizer, 22 peak detection type detector, 23
Memory, 24 reliability evaluator, 30 data detector, 31 equalizer, 32 Viterbi decoder, 33
Memory, 34 reliability evaluator, 40 comparator, 5
0 selector, 60 digital signal processor

Claims (5)

[Claims] 1. Decoding means for decoding an input digital signal under a plurality of different conditions, and evaluation means for evaluating the reliability of each of a plurality of decoded data decoded under the different conditions. A data processing device, comprising: a selection unit that selects one piece of decoded data from the plurality of pieces of decoded data in accordance with the evaluation result of the evaluation unit. 2. The data processing device according to claim 1, wherein the evaluation means evaluates the reliability by using an error correction code attached to the digital signal. 3. The synthesizing unit according to claim 2, further comprising a synthesizing unit that synthesizes respective outputs of the plurality of decoding units into new decoded data corresponding to a correction result by the error correction code. The described data processing device. 4. The equalization means for equalizing the digital signal is further provided, and the evaluation means evaluates the reliability by using an equalization error by the equalization means. The described data processing device. 5. The input digital signal is decoded under a plurality of conditions different from each other, the reliability of each of a plurality of decoded data decoded under the plurality of conditions different from each other is evaluated, and the reliability is evaluated. Then, one piece of decoded data is selected from the plurality of pieces of decoded data.