CN1298179A - CD-ROM decoder mistakenly change prevention device - Google Patents

Abstract

A device for preventing error modification of CD-ROM drive decoder is composed of phase-locked loop, synchronous signal detector, demodulator, cross code decoder and data filler. The erasure position memory is connected with the inner code flag, the position comparator is used for comparing whether the error position sent by the RS code decoder is consistent with the position stored in the erasure position memory, thereby forming a method which can determine whether to correct according to the state of the inner code flag when carrying out data correction operation, and can prevent the improper increase of error correction rate under the condition of a large number of data errors.

Description

CD-ROM decoder mistakenly change prevention device

The present invention relates to an optical disc player decoder in a digital data processing device in the field of instruments, in particular to a related structure mainly for correcting the internal data of an improved optical disc decoder so that the miscorrection rate (MISCORRECTION RATE) does not exceed Excessive deterioration, in order to maintain the output quality of the CD-ROM decoder mistakenly change the prevention device.

Nowadays, due to differences in optical disc compression technology and manufacturers' different quality requirements for optical disc products, various errors occur. Generally, errors can be divided into random errors and brust errors of large blocks. These errors can be properly corrected or corrected by the interleaved code decoder (CIRC DECODER) in the CD decoder. The following is a brief introduction to the existing traditional CD decoders.

Please refer to Fig. 5, which is a block diagram of an existing traditional optical disc decoder. The NRZI data read from the optical disc, in addition to being converted into 16-bit PCM data RFDATA, passes through a phase-locked loop 91 (DATA SLICER&RECOVERY), synchronous signal detector 92 (SYNCHRONOUS PATTERN DETECTION), 14-to-8-bit demodulator 93 (14-8DEMODULATOR), interleaved code decoder 94 (CIRC DECODER), and data filler 95 (DATACONCEALMENT) , and finally send out the decoded real data. Since the data written on the optical disc has considered the problem of error correction, the data is arranged in a staggered manner, rather than in a continuous series, so as to facilitate correction or correction in the subsequent reproduction and decoding process, while in the aforementioned circuit The interleaved code decoder 94 (CIRC DECODER) contains a de-interleaved code decoder, and can also detect the location and quantity of errors at the same time, and can be corrected or corrected in a timely manner through the built-in corrector. To achieve the effect of restoring data. For the data that cannot be corrected or corrected in time by the interleaved code decoder 94, a repair flag (flag) signal is sent to the next-level data padding device 95 to notify the data padding device 95 to repair or correct the data. filled job. The data filler 95 performs "interpolation" (interpolation) processing on the data area to be repaired, that is, inserts a "false data" equal to the amplitude average value of the previous and subsequent data for the position lacking data, so as to achieve The so-called patching or filling effect.

The type of inserting false data of the aforementioned data filler 95 can only make the data uninterrupted at best, and can only be applied to music CDs or audio-visual CDs, and is not suitable for data storage CDs. On the error correction capability of the interleaved code decoder 94, it still has a good effect on a small amount of errors, but for the burst error (burst error) problem in a large block area, due to the limitation of its structure, its maximum correction is allowed. The range is when the error is less than or equal to 2. If it exceeds this range, it is quite easy to have a miscorrection problem, which will lead to an abnormal deterioration of the miscorrection rate. The present invention mainly intends to improve this problem, so as to ensure that the error rate will not deteriorate.

In view of the defects in the above-mentioned existing CD player decoders, the inventors actively researched and innovated based on rich practical experience and professional knowledge. After continuous research, design, and repeated trial samples and improvements, they finally created out the present invention.

The main purpose of the present invention is to overcome the defects existing in the existing CD player decoder, and provide a kind of CD player decoder error prevention device, so that it is mainly between the internal decoder and the corrector of the interleaved code decoder. An error judgment unit is added. This error judgment unit can refer to the state of the internal code flag (INNER-CODE FLAG) to decide whether to perform data correction when an error occurs, so as to avoid deterioration of the error rate. .

Another object of the present invention is to provide a device for preventing erroneous change of a CD player decoder, so that the erroneous change judgment unit can be composed of an erase location memory (ERASURE LOCATION MEMORY) and a location comparator (LOCATION COMPARATOR). When the internal code flag signal of the memory represents the correct state, the error position is recorded, and when the position comparator detects that the decoder sends the same position information, it notifies the corrector of the interleaved code decoder to correct the data, which constitutes a Check the internal code flag to determine whether to correct the wrong data, so as to achieve the effect of maintaining a low error correction rate.

The purpose of the present invention is achieved by the following technical solutions. According to the present invention, an optical disc player decoder error prevention device is provided. The optical disc decoder is formed by a phase-locked loop, a synchronous signal detector, a demodulator, an interleaved code decoder, and a data filling device. It is characterized in that: An error correction judging unit device is additionally provided. The error correction judging unit device is arranged between the interleaved code decoder and the data filling device. It is composed of an error position memory device and a position comparator. The internal code flag signal output terminal of the code decoder is connected, and the error position memory outputs the position signal. The output terminal of the output position signal is connected with a position input terminal of the position comparator, and the other position input terminal of the position comparator is connected with the interleaving The decoded error position output signal sent by the code decoder is connected.

The purpose of the present invention can also be further achieved through the following technical measures. In the above-mentioned device for preventing erroneous modification of the CD player decoder, the position comparator further has a control signal terminal connected to the error message output terminal of the interleaved code decoder.

Compared with the prior art, the present invention has obvious advantages and positive effects. From the above technical solutions, it can be seen that the device for preventing erroneous modification of the CD player decoder of the present invention is mainly a device in which a erroneous modification judging unit is arranged between the interleaved code decoder (CIRCDECODER) and the data patcher (DATA COMCEALMENT). This unit is composed of ERASURE LOCATION MEMORY and LOCATION COMPARATOR. The erasing position memory is connected with the internal code flag (INNER-CODE FLAG), and the position comparator is used to compare whether the error position sent by the RS code decoder is consistent with the position stored in the erasing position memory. One is to determine whether to correct according to the state of the internal code flag when performing data correction, so as to prevent the improper increase of the error rate in the case of a large number of data errors.

To sum up, the present invention mainly adds an error correction judgment unit between the internal decoder and the corrector of the interleaved code decoder. The error correction judgment unit can refer to the internal code flag when an error occurs. The state determines whether to perform data correction operation, so as to avoid the deterioration of the false change rate; the false change judgment unit can be composed of an erasing position memory and a position comparator, and the internal code flag signal of the erasing position memory represents the correct state When the position comparator detects that the decoder sends the same position information, it notifies the corrector of the interleaved code decoder to correct the data, which constitutes a method that can be judged by checking the internal code flag. Correction of erroneous data can achieve the effect of maintaining a low error correction rate. It has great improvements in both structure and function, and has made great progress in technology, and has produced easy-to-use and practical effects, and indeed has enhanced efficacy, so that it is more suitable for practical use. It is a novel, Progressive, practical new design.

The specific structure of the present invention is given in detail by the following examples and accompanying drawings.

Fig. 1 is a block diagram of a modified optical disc decoder of the present invention.

Fig. 2 is a schematic diagram of distribution of internal and external code data of the optical disc of the present invention.

Fig. 3 is an action flow chart of an embodiment of the present invention.

Fig. 4 is a block diagram of an embodiment of a wrongly modified judging unit of the present invention.

FIG. 5 is a block diagram of an existing conventional optical disc decoder.

In the following, the specific structure, features and functions of the anti-mismodification device for optical disc player and decoder proposed according to the present invention will be described in detail below in conjunction with the accompanying drawings and preferred embodiments.

Please refer to FIG. 1 , the device for preventing erroneous modification of a disc player decoder according to the present invention mainly sets an erroneous modification judgment unit 10 between the interleaved code decoder 94 and the data filler 95 in the existing traditional disc decoder. The false correction judging unit 10 filters wrong data to determine whether to correct or correct, so as to ensure that the false correction rate will not deteriorate.

This error judgment unit 10 mainly refers to the state of the inner code flag (INNER CODE FLAG) to judge whether to correct or correct the wrong data position, because the inner code flag is for commending whether the inner code section is correct or not, This ensures that its error rate does not worsen. The following is a brief description of the type of optical disc encoding. As shown in the distribution diagram of the inner and outer codes of the optical disc in Figure 2, the data is in the form of multi-layer encoding in order to achieve the characteristics of correction and restoration. The first layer of encoding is It is called "INNER CODE", which is arranged vertically and adjacently; the second layer is arranged horizontally and adjacently from top to bottom, called "OUTER CODE". At the same time, there is an inner code flag (INNER CODE FLAG). Each bit in the flag indicates whether the data of each inner code segment is correct or not. If the corresponding inner code flag is 0, it means that the inner code data is correct. No error; on the contrary, if it is 1, it means that there is an error in the inner code. The present invention uses this internal code flag as the judgment condition of whether the data is corrected or not. If the internal code flag at the place where the error occurs is 0, then the data at this position can be corrected. If the internal code flag is 1, No correction is made. Therefore, the present invention utilizes the characteristic of the internal code flag to commend the correctness of the internal code position data, and uses it as a filter condition for whether to perform data correction, so that the error rate of the entire decoding system will not deteriorate and remain at a good correctness. Rate.

In actual implementation, there may be many different implementation forms based on the above-mentioned internal code flag as the judgment condition of whether the data is corrected or not. The following is an example to illustrate. As shown in the block diagram of the embodiment in FIG. 4 , for the sake of illustration, only the existing conventional interleaved code decoder 94 in FIG. 1 and the error judgment unit 10 of the present invention are shown. The erasure flag counter 941 that is positioned at the peripheral position of Fig. 4, RS code decoder 942 RS-CODE DECODER (Reed-Solomen CODE DECODER), and corrector 943 belong to the interior of interleaved code decoder 94 (CIRC DECODER) among Fig. 1 . The erase flag counter 941 is connected with the inner-code flag (Inner-code flag), and can be used to accumulate data error (ERROR), that is, an error whose location and content are unknown, and erase ERASRE, that is, the location is known but the content is unknown The number of errors, the RS code decoder 942 deinterleaves the input outer code data (outer-code data), and at the same time according to the status of the inner code flag sent by the erasure flag counter 941 and the error or erasure The accumulated value is analyzed to find out the error location (Error Location) and the wrong value (ErrorMagnitude), which are sent to the corrector 943 on the right side of the drawing for data correction or correction, and finally the corrected data (Corrected Data) is sent out.

The error judgment unit 10 of the present invention is inserted between the RS code decoder 942 and the corrector 943 of the interleaved code decoder 94 . This wrong change judging unit 10 can be made up of an erasure location memory 11 (erasure location memory) and a position comparator 12 (location comparator), and this erasure location memory 11 is connected with the inner code flag signal, and can according to the inner code flag signal The state of the code flag is used to record the wrong position signal, and at the same time, the output of the erased position memory device 11 is sent to the position comparator 12 for position comparison with the wrong position signal sent by the RS code decoder 942. If If the comparison position is consistent, it means that the position where the error occurs can be corrected or corrected, so the position comparator 12 sends a "correction signal" to inform the corrector 943 on the right side of the drawing to correct the data, and the rest is not recorded. No correction processing is skipped for error locations that can be corrected, thereby preventing the rate of false corrections from deteriorating.

In the foregoing Fig. 4, various error messages sent by the RS code decoder 942, such as residual value (SYNDROME), error count (ERROR COUNT), erasure count (ERASRE COUNT), and other error messages can be passed through a The CAS output terminal is sent to the error correction judgment unit 10, and is further used as the judgment condition for correction according to the quantity of errors, and only under some conditions, it is processed by the aforementioned method, as shown in Fig. 3, one embodiment action As shown in the flowchart, the residual value is judged sequentially, 1 error count, 2 error counts, 2 erasure counts plus 1 error count 2 ERASURE+1 ERROR, and conditions such as greater than 4 erasure counts. Wherein the residual value (SYNDROME) in the action flow chart is the final value indicating whether the data is correct. If it is zero, it means no error, if it is not zero, it means that an error occurred. Therefore, in the process of judging that the residual value is not equal to zero, the following conditional judgment and action flow are performed, and when the error count is known to be less than or equal to 1, the error correction process is directly performed without further judgment, because When the error count is 1, it is within the allowable range, and will not cause the error rate to deteriorate. When the erasure count is greater than 4 at the bottom of the picture, it is skipped and not processed. When the erasure count is equal to 1, equal to In the case of 3, no judgment is made, and the correction is made directly through the correction steps at the bottom of the drawing, because it has no effect on the error correction rate. Check and filter the internal code flag only under the condition that the error count is 2 and there are 2 erase counts plus 1 error count. If the internal code flag is checked to be the correct value, and the The position comparator 12 performs error correction processing when comparing the wrong position.

The determination condition set in the above-mentioned embodiment flow chart of FIG. 3 is only one implementation situation, and can also be moderately adjusted to meet actual needs, and is not a limiting condition. The key of the present invention to prevent the false modification rate from deteriorating is to increase the judgment and filtering of the internal code flag to solve the above-mentioned problems and obtain improved effects.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still belong to within the scope of the technical solutions of the present invention.

Claims (2)

1. An optical disc player decoder error prevention device, with a phase-locked loop, a synchronous signal detector, a demodulator, an interleaved code decoder and a data filler to form a disc decoder, characterized in that: It is additionally equipped with an error judgment unit device, which is arranged between the interleaved code decoder and the data filling device, and is composed of an error position memory device and a position comparator, and the input terminal of the error position memory device is connected to the The internal code flag signal output terminal of the interleaved code decoder is connected, and the error position memory device outputs a position signal. The output terminal of this output position signal is connected with a position input terminal of the position comparator, and the other position input terminal of the position comparator is connected with the position input terminal of the position comparator. The decoded error position output signal sent by the interleaved code decoder is connected. 2. The device for preventing error modification of the optical disc player decoder according to claim 1, characterized in that said position comparator further has a control signal terminal connected to the error message output terminal of the interleaved code decoder.

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