JPH0341676A - Digital signal reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a digital signal reproducing apparatus that records and reproduces data using an error correction code having a double or more encoding structure.

2. Description of the Related Art In recent years, in signal reproducing apparatuses, it has been considered to perform recording and reproducing using digital signals.

An example of the above-mentioned conventional signal reproducing device will be described below with reference to the drawings.

FIG. 3 is a block diagram showing the general configuration of a conventional digital signal reproducing device. In FIG. 3, 11 is a second code decoder, and 12 is a first code decoder. The operation of the signal reproducing device configured as described above will be explained below.

Since the symbol array of one received word sent from the recording medium and having a double encoded structure has a two-dimensional planar structure, the received word is first divided into rows and input to the second code decoder 11. be done. After signal processing is performed by the second code decoder 11, signal processing is performed by the first code decoder 12, and a decoded information signal is output.

FIG. 4 shows an example of a block diagram of a signal processing section of a digital signal reproducing apparatus for digital signals that performs digital recording by performing shattling.

In FIG. 4, 13 is a second code decoder.

14 is a first deshuffling device. 15 is a first code decoder. 16 is a second deshuffling device.

The operation of the signal reproducing device configured as described above will be explained below.

Since the symbol array of one received word sent from the recording medium and having a double encoded structure has a two-dimensional planar structure, the received word is first divided into rows and input to the second code decoder 13. be done. This second code decoder 13 corrects single errors and detects some of the errors that are double errors or more. If detected, an error detection flag is set to indicate that an error exists in that line. The first deshuffling device 14 performs deshuffling, and the signal is subsequently divided column by column and input to the first code decoder 15 . The first code decoder 15 can correct double or less erasure errors. Therefore, the first code decoder 15 detects the error positions for which the error detection flag has been set by the second code decoder 13 for each column, and detects if there are two or less erasure errors in one column. Perform the correction, otherwise do not make the correction, for all columns. Thereafter, deshuffling is performed by the second deshuffling device 16 to produce an information signal.

Problem to be Solved by the Invention However, with the above configuration, if three or more errors occur in the same line in the second code, it may be determined that there is no error, and in such a case, it is necessary to correct the error. The problem was that it was converted into an information signal without any processing.

In view of the above-mentioned problems, the present invention has been developed to detect errors in most cases even when three or more errors occur in the same line and it is determined that there is no error in decoding the second code, and the error is corrected. The present invention provides a digital signal reproducing device that outputs correct information signals.

Means for Solving the Problems In order to solve the above problems, the digital signal reproducing apparatus of the present invention includes a second first code decoder and a second second code decoder that decode in a decoding order different from the conventional decoding order. a decoder;
A second code syndrome checker whose output differs depending on the syndrome value of the second code, and an output from the first first code decoder and a second second code decoder based on the output of the second code syndrome checker. It is equipped with an input switching circuit that outputs either one of the output and the output.

Effect of the Invention With the above-described configuration, the present invention allows the first code decoder to determine that an error has occurred even in most cases where the second code decoder determines that there is no error when three or more errors occur in the same row. By subsequently correcting the error using the second code decoder, a correct information signal can be obtained.

Embodiment Hereinafter, a digital signal reproducing apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a digital signal processing section of a digital signal reproducing apparatus according to a first embodiment of the present invention. In FIG. 1, 1 is a second code syndrome Si calculator, 2 is a first second code decoder, 3 is a first first code decoder, 4 is a second code syndrome checker, and 5 is a second code syndrome checker. a first code decoder of 6
is a second second code decoder, and 7 is an input switching circuit.

The operation of the digital signal reproducing apparatus configured as described above will be explained below with reference to FIG.

A received word whose symbol array has a two-dimensional planar structure transmitted from a recording medium is divided into rows and input into a second code syndrome St calculator I and a first second code decoder 2. At the same time, it is divided into each column and the second
is input to the first code decoder 5. The output of the first second code decoder 2 is sent to the input switching circuit 7 via the first first code decoder 3. Further, the output of the second first code decoder 5 is sent to the input switching circuit 7 via the second second code decoder 6. The input switching circuit 7 uses the output from the second second code decoder 6 as an information signal when the syndromes of each row calculated by the second code syndrome checker 4 are all 0,
If at least one of the syndromes in each row calculated by the second sign syndrome calculator 1 is not O, the first
The output from the first code decoder 3 is used as an information signal.

As described above, according to this embodiment, by providing a manual switching circuit that can switch the output signal by a decoder that performs decoding in an order different from the conventional decoding order and a second code syndrome checker, the same In most cases where three or more errors occur in a row and the second code decoder determines that there is no error, the first code decoder can determine that an error has occurred and correct it, and then the second code decoder A correct information signal can be obtained by correcting errors using the decoder. Further, in the first embodiment, an input switching circuit is installed at the final stage of the signal, but it goes without saying that this may be placed before the decoder.

A second embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram of a signal processing section of a digital signal reproducing apparatus showing a second embodiment of the present invention. 21 is the second code syndrome Si calculator, 22 is the first
a second code decoder, 32, a first first code decoder, 23;
26 is a second code syndrome checker, 26 is a second first code decoder, 29 is a second second code decoder, and 24 is a manual switching circuit, which is the same as the configuration shown in FIG. be. The difference from the configuration shown in FIG. 1 is that a first de-shuffling device 25, a first code encoder 27, a first shuffling device 28, and a second de-shuffling device 33 are provided.

As shown in FIG. 2, by providing a de-shuffling device, a first code encoder, and a shuffling device as shown in FIG. The effect of this can be obtained. For example, D-
If applied to a one-system digital VTR, etc., a single error correction method is used as the decoding method of the second first code decoder 26, and a double error correction method is used as the decoding method of the second second code decoder 29. By using it, the effects of the present invention can be easily obtained.

In addition, by using the double error correction method as the decoding method of the second first code decoder 26 and using the triple error correction method as the decoding method of the second second code decoder 29, the D-2 system The effects of the present invention can also be easily obtained for digital VTRs.

In the second embodiment, the input switching circuit is inserted at the final stage of the signal, but it goes without saying that this circuit may be placed before the first deciphering device.

Effects of the Invention As described above, the digital signal reproducing apparatus of the present invention includes a first code decoder and a second code decoder that decode in a decoding order different from the conventional decoding order, and a syndrome value of the second code. By providing a second code syndrome checker with different outputs depending on the output, and an input switching circuit that outputs one of the two inputs depending on the output of the second code syndrome checker, triple Even in the majority of cases where the above errors occur and the second code decoder determines that there is no error, the first code decoder can determine that an error has occurred and correct it, and the second code decoder continues to Correct information signals can be obtained by correcting errors.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a digital signal reproducing apparatus according to a first embodiment of the present invention, FIG. 2 is a block diagram of a digital signal reproducing apparatus according to a second embodiment of the present invention, and FIG. 3 is a block diagram of a conventional digital signal reproducing apparatus. Block Diagram of Reproducing Apparatus FIG. 4 is a block diagram of a conventional digital signal reproducing apparatus that performs shirt ringing. l...Second sign syndrome calculator, 2...
...First second code decoder, 3...First first code decoder, 4...Syndrome checker, 5
... Second first code decoder, 6 ... Second second code decoder, 7 ... Input switching circuit.

Claims (1)

[Claims] a second code syndrome calculator that calculates the syndrome of a second code of a code having a double or more encoding structure;
a first second code decoder that receives a code having a double or more encoding structure as an input signal and decodes a second code of the code having a double or more encoding structure; a first code decoder that decodes the first code of a code having a double or more encoding structure based on the output of the second code decoder; and the output of the second code syndrome calculator. a second code syndrome checker that outputs different values depending on when all the syndromes of the second code are 0 and when they are not; a second first code decoder that can use a different decoding method from the first first code decoder; A second second code decoder that can use a decoding method different from that of the code decoder; and an input switching circuit that outputs either the output from the second code decoder.