JPS626469A - Interpolating device for error correction - Google Patents

Abstract

PURPOSE:To prevent the mixed regeneration of data obtained before and after the interruption of data by interleaving when the data interruption is occured by generating a flag indicating a data error during the period up to the completion of interleaving. CONSTITUTION:Data read out from a recording medium are written in a data memory circuit 1 in the alphabetical order. If the data are discontinued due to a track shift or the like on the way of data writing in the alphabetical order, a flag generating circuit 3 detects the interruption of data on the basis of a tracking signal indicating the track shift and writes a flag indicating the data error of a frame in a position corresponding to a pair of data arrayed alphabetically in the memory circuit. Thus, the mixing phenomenon of data obtained before and after the interruption which is generated by interleaving at the reproducing of the interrupted part of data can be prevented and the remarkable deterioration of reproduced sound can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an error correction interpolation device for digital audio equipment that digitizes temporally continuous audio signals and records and reproduces them.

BACKGROUND OF THE INVENTION In recent years, with the spread of digital audio equipment, error correction methods have been developed using a combination of interleaving, which changes the order of recorded data, and error correction codes, which detect data errors and perform correction or interpolation. The ones that exist are the mainstream.

An example of the above-mentioned conventional error correction interpolation device will be described below with reference to the drawings. 3a and 4 show the operation and configuration of a conventional error correction interpolation device.

In FIG. 4, 1 is a memory circuit, 2 is an error correction interpolation circuit, and the output of the memory circuit 1 is input to the error correction interpolation circuit.

The operation of the error correction interpolation circuit configured as described above will be explained below.

First, error correction codes are used to correct errors caused by data reading errors when reading data on a recording medium, but if errors occur continuously, they cannot be corrected, so data must be rearranged to avoid this. Interleaving is also performed. FIG. 2 shows the arrangement of data within the memory circuit 1 for which interleaving is to be performed. During recording, the data is written in the direction of ABC...F to which an error correction code is added, and is read out in the direction of abc...F in the figure. It will be recorded. As a result, the order of the recorded data is different from the original, and even if errors occur continuously in the data during reproduction, they become isolated errors and can be corrected during error correction.

Next, during reproduction, the data read from the recording medium is written into the memory circuit 1 in the order of abc...f in FIG. The written data is shown in Figure 2.
. . . are read out in the order of F, input to the error correction interpolation circuit 2, where errors are corrected. If correction is not possible, interpolation is performed using temporally consecutive data. (For example, "Compact Disc Reader" Ohmsha, S6A, 103-1
(page 10).

Problems to be Solved by the Invention However, with the above configuration, if the pickup of a compact disc playback device moves to another track due to scratches or vibrations on the disc, data will be interrupted and the data will be lost. It becomes discontinuous. In FIG. 2, if a data disconnection occurs at the write position abc...f in the figure, the subsequent data will no longer be connected to the previous data, and the read data will be BICL-...
The period up to reading F' is discontinuous. Of course, since it is not a correct code word, error correction cannot be performed, and if this code word is output as is, an audio signal as shown in Figure 3 (B) will be reproduced. In FIG. 3a, the first half shows the data before the break occurs, and the second half shows the data after the break. The middle part shows how the data before and after the break are mixed together due to interleaving. When this data is reproduced as sound, the portion where the data is mixed becomes large noise, which has the problem of significantly deteriorating the sound quality.

In view of the above problems, the present invention provides an error correction interpolation device that prevents data before and after the data discontinuity from being mixed and reproduced by interleaving when a data discontinuation occurs, and improves the sound quality of reproduced sound. It is something.

Means for Solving the Problems In order to solve the above problems, the error correction interpolation device of the present invention includes a memory circuit that performs data interleaving by changing the order of writing and reading data, and a memory circuit that interleaves data by writing and reading data in different orders. Interleaving is completed with an error correction interpolation circuit that detects and corrects or interpolates errors in the data written to the memory circuit, and a flag that detects discontinuous points in the data written to the memory circuit from the tracking signal and indicates that there is an error in the data. This circuit consists of a flag generation circuit that generates a flag that is generated during a period of time until the flag is generated and is written to the memory circuit, and is configured to correct or interpolate the data written to the memory circuit during the period when this flag is generated, assuming that it is an error. It is.

Effect of the present invention With the above-described configuration, a flag is added to indicate that there is an error in the data after data discontinuation occurs,
By correcting or interpolating the data with this flag after solving the interleaving, only the data before the break is reproduced and output, preventing the data after the break from being mixed in, and the flag is set after the interleaving is completed. By stopping the addition, only the data after the interruption continues to be reproduced and output, so the sound quality is improved without mixing the data before and after the interruption.

Embodiment Hereinafter, an error correction interpolation device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of an error correction interpolation device in a first embodiment of the present invention. In FIG. 1, 1 is a memory circuit, 2 is an error correction interpolation circuit, and 3 is a flag generation circuit. The output of the flag generation circuit 3 is input to the memory circuit 1, and the output of the memory circuit 3 is input to the error correction circuit 2. This is the configuration that will be used.

The operation of the error correction interpolation device configured as described above will be described below with reference to FIGS. 1 and 2.

First, FIG. 2 shows the arrangement of data in the memory circuit 1. Data read from the recording medium is written to the memory circuit 1 in the order of abc...f in FIG. I'm going to go. If discontinuity occurs in the data due to track deviation while writing data to abc...f, the flag generation circuit 3 detects the data discontinuity from the tracking signal indicating the track deviation, and writes the data to the memory. A flag indicating that the data of the frame is incorrect is written at a position corresponding to the - set data of abc...f (this is called a frame) in the circuit. From then on, until the data of frames abc...f in which this discontinuity occurred is no longer included in the data read out from the memory circuit, that is, aB'C'...F' in FIG. A flag indicating that there is an error is written at the position corresponding to the frame up to the frame containing the data at the read position (this is referred to as the period during which interleaving is completed).

There is no need to write a flag to a frame containing data F'. However, when reading the data of aB'C'...F', the data up to axK' has a flag indicating an error and will not be reproduced and output.
Even if F' is reproduced and output without error, the data before the interruption will not be mixed in.

From then on, the frame data including data B' to E' is flagged as an error, so it is not reproduced and output.
The number gradually decreased, and as shown in Figure 2, "B" and "C"...
. . . At the time of reading the data of "F", all the data are determined to be error-free and are reproduced and output.

Figure 3 shows the situation. The first half of the waveform shows the data before the break, and the dotted line shows the data after the break.

Since the data indicated by the dotted line has the above-mentioned flag, it is not reproduced and output, but is corrected or interpolated by the error correction interpolation circuit 2, and the data before the interruption is re-corrected and output. At the time when the data of F' is read out from the memory circuit 3, the waveform shifts to the data after the discontinuation. This waveform further passes through a low-pass filter to prevent aliasing, so it is reproduced as a smooth sound.

As described above, according to this embodiment, a discontinuous point in data written to a memory circuit is detected from a tracking signal, etc., and a flag indicating that there is an error in the data is generated until the interleaving is completed. By providing a flag generation circuit that is written into the circuit, it is possible to prevent the phenomenon in which data before and after the break are mixed together due to interleaving when playing back the discontinuous portion of data, thereby improving the significant deterioration of the reproduced sound quality. be able to.

Note that the tracking signal is a signal output from the servo circuit of the pickup, and is a signal indicating whether or not the track is off track with a value of 1 or 0.

Effects of the Invention As described above, the present invention detects a discontinuous point in data written to a memory circuit and generates a flag indicating that there is an error in the data until interleaving is completed and writes the flag to the memory circuit. By providing the generating circuit, it is possible to prevent the mixing of data before and after the discontinuation caused by interleaving when reproducing and outputting the discontinuous portion of data, and therefore it is possible to improve the deterioration of the reproduced sound quality.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an error correction interpolation device according to a first embodiment of the present invention, FIG. 2 is a diagram showing a data arrangement in the memory circuit of FIG. 1, and FIG. 3 is a diagram showing the effects of the present invention. FIG. 4 is a block diagram of a conventional error correction interpolation device. 1...Memory circuit, 2...Error correction interpolation circuit, 3...Flag generation circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Figure? Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] a memory circuit that interleaves data by different data writing and reading orders; an error correction interpolation circuit that detects and corrects or interpolates errors in data read from the memory circuit; The error correction interpolation circuit includes a flag generation circuit that detects a discontinuous point in data to be written from a tracking signal and generates a flag indicating that there is an error in the data, and writes the flag to the memory circuit. An error correction interpolation device characterized by correcting or interpolating data written in the memory circuit during a period in which an error is occurring.