JPS59213008A - Pcm recording and reproducing device - Google Patents

Abstract

PURPOSE:To execute a correcting processing such as a mean value interpolation, etc. even in case of an error exceeding an error correcting capacity on a recording medium by encoding each odd sample group and even sample group, and separating each adjacent odd sample and even sample by an interleave. CONSTITUTION:An odd sample word and an even sample word are stored by each word unit in a memory circuir 46, and when for instance, (n) is even- sampled by an error correcting encoder 48 with respect to each sampling word read out of this memory circuit 46, two error correcting words are added. As for each sample word to which the error correcting word has been added, an inter- leave of D=16 blocks is performed to each sampling signal word in one error correcting code block, and error correcting words of P and Q by an interleave circuit 50, and also an odd sampling signal word and its error correcting word are delayed by a constant interval of time C. Thereafter, a cyclic code is added by an error detecting encoder 52, and recorded in a recording medium through a modulator 54 and rotary heads 56, 58.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a PCM recording and reproducing apparatus, and particularly to a PCM recording and reproducing apparatus that interleaves data arrangement in an encoding/decoding means and a code decoder.

This type of PCM recording and playback device is DAD (
Digital audio disc) player, based on the consumer PCM encoder/decoder of Stereo Technology Committee/Video Technology Committee File 5TC-007 of the Electronics Industries Association of Japan (EIAJ) <P CM adapter or commercial 2-channel/ channel or multi-channel PC
There are M recording and reproducing devices. Each of the above-mentioned devices is provided with an encoding/decoding means for error correction, etc., and interleaving for dispersing the worst errors on the recording medium before and after the encoding/decoding means.

As a conventional PCM recording and reproducing device, for example, the above-mentioned EI
The <PCM7 adapter will be explained based on AJ 8TC-007 with reference to FIGS. 1 and 2.

In FIG. 1, IOL and IOR are input terminals for left and right channels of audio signals, 12 is a low-pass filter for band limiting, 14 is an analog-to-digital converter, 16 is an encoder for error correction, and 18 is an analog-to-digital converter. is an interleaving circuit, and 20 is a cyclic code (CRC) for error detection.
), 22 is a pseudo video signal generation circuit, 24 is an output terminal for the pseudo video signal, and a video tape recorder is connected to the output terminal 24.

Further, 26 is an input terminal to which a pseudo video signal reproduced from a video tape recorder is supplied, 28 is a synchronization signal separation circuit, 30 is an error detection decoder that checks a cyclic code, 32 is a dinterleave circuit, and 34 is an error correction decoder, 36 is a correction circuit for correcting data whose errors are not corrected, 38 is a digital-to-analog converter, 40 is a low-pass filter, and 42L and 42R are the outputs of the left and right channels of the audio signal. A terminal 44 is a clock generation circuit that supplies clocks to each of the circuits.

Next, the operation will be explained. Person, power terminal 10L and 10
The left and right channel audio signals supplied to R1 are converted into digital signals by an analog-to-digital converter 14 via a low-pass filter 12, and then converted into digital signals by an error correction encoder 16 into the following two error correction words. P,Q
is added.

P n -A n■Bn■An+s■Bn+1eAn+
2■Bn+zQ, n = T'An■T'BnflT
'An+t■T3Bn+x■T'An+g■TBn+z
where An and Bn are the analog-to-digital converted sampled signal words of the left and right channel signals, n is the address of the sampled signal, and ■ is the modulo '2'' for each corresponding bit of each word. The addition, T!-!Q, is the generating matrix.

The signal to which the error correction code has been added is processed by the interleaving circuit 18, which divides each sampled signal word within one error correction block and the P and Q error correction words into a D-16 block, as shown in FIG. Interleaving (crossing) is applied. In FIG. 2, N, N+1, . . . are block numbers, and the block containing An is the error detection encoder 2.
An error detection word (CRC) is added at 0, and the signal is converted into a pseudo video signal by the video signal generation circuit 22 in the order of the block number, sent to the output terminal 24, and recorded on a video tape recorder.

On the other hand, when the pseudo video signal recorded on the video tape recorder is reproduced and supplied to the input terminal 26, the synchronization signal is first separated in the synchronization signal separation circuit 28, and error detection is performed in the error detection decoder 30. , dinterleave circuit 3
At step 2, an operation completely opposite to that of the above-mentioned interface circuit 18 is performed to return the data string that generated the error correction word. Thereafter, correctable errors are corrected in the error correction decoder 34, and corrections such as average value interpolation are performed in the correction circuit 36 for uncorrectable errors, and then the digital-to-analog converter 3
8 is converted into an analog signal, which is sent to output terminals 42L and 42R via a low-pass filter 40.

Note that interleaving is performed to improve the Nost error correction capability, and in this case, if an error detection code is also used, Nost errors up to 2D blocks can be corrected.

The conventional PCM recording and reproducing device is configured as described above.
- If a Nost error larger than 2D occurs in Ruri, it cannot be corrected and is corrected by the correction circuit 36. A simple and effective correction method for the correction circuit 36 is average value interpolation. In order to perform this average value interpolation, the data before and after must be correct data. Here, in FIG. 2, if a node-st error of length 2D+1 occurs from the Nth block, since L- can only correct up to two errors in one error correction code, An, BnSAn+*, Bn-3D
, B n + 1-3D.

The sampling word P of . . . becomes a correction. However,
Since An, A n + 1, etc. are continuous data, it is not possible to perform average value interpolation, which has the disadvantage of generating audible noise.

In addition, in general PCM recording and reproducing devices, when an error that exceeds the error correction capability occurs, an error correction code is configured to
・In many cases, all data must be corrected, which has the disadvantage that it is more likely to generate noise.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to encode an audio signal in odd sample group and even sample group units, and to separate adjacent odd and even samples. , Exceeds error correction ability No. 9-
An object of the present invention is to provide a PCM recording and reproducing device that can reduce the generation of noise even when a recording error occurs.

In order to achieve the above object, the present invention provides a PC that samples an audio signal, converts it into a digital signal, records it on a recording medium such as a magnetic tape, and reproduces it from the recording medium.
In the M recording and reproducing apparatus, an encoding means adds a code for error correction or error detection to the odd sample group and even sample group of the digital signal, respectively, and the code including the odd sample group and the code concatenated therewith. A recording system comprising an interleaving means for separating and interleaving a code including an even sample group, a dinterleaving means for performing an operation opposite to the interleaving means, a decoding means for detecting or correcting an error, and a correction means. The present invention is characterized in that it includes at least one of a reproduction system and a reproduction system equipped with means for correcting irreversible errors.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 3 is a block diagram of a rotary head type PCM recording/reproducing apparatus according to the present invention, and FIG. 4 is a data layout diagram thereof.

In FIG. 3, 46 is a memory circuit that stores odd sample words and even sample words of the digital signal from the analog-to-digital converter 14 in excess of the number of words constituting one error correction code. Reference numeral 48 denotes an error correction encoder for adding an error correction word to the odd sample word group and the even sample word group sequentially read out from the memory circuit 46;
52 is an error detection encoder; a modulator that converts into a signal sequence suitable for recording on a recording medium such as a magnetic tape;
56 and 58 are rotary heads for recording and reproducing, and 60 is a changeover switch for selecting one of recording and reproducing, and these constitute a recording system. 62 is a changeover switch that selects the head to which the reproduction signal is input; 64 is a demodulator that converts the reproduction signal reproduced from the recording medium into a digital signal;
66 is an error detection decoder, 68 is a dinterleave circuit that returns the error correction code to the generated time sequence, 70 is an error correction decoder, and 72 is an even sample word and an odd sample word each forming one error correction code. A memory circuit 74 is a correction circuit that performs average value interpolation, and a reproduction system is comprised of these, a digital-to-analog converter 38, and a low-pass filter 40. 76 is a clock generation circuit that supplies clock signals to each circuit.

Next, the operation will be explained. The memory circuit 46 stores odd sample words and even sample words in units of words, and when the error correction encoder 48 converts n into an even sample in each sampled word read from the memory circuit 46, The following two error correction words are added.

That is, for even sample words, Pn=An■B n(I)A n +2■Bn+2■A
n-z■Bn+nQn =-T'An@T'Bn@'I
“An + x■T” Bn+z■T”An ra■TB
For n+4 odd sample words (・Pn+ t = An+ 1■Bn+1■An+s■Bn
+ a■An+s■Bn+sQn + s -T'An
+ t■T'B n + s■T' An + s■
Error prevention words represented by T"Bn+i*T"An+s*TBn+s are respectively added.

Each sample word to which these error correction words r have been added is processed by an interleave circuit 50, as shown in FIG.
The Q error correction words are interleaved by D=16 blocks, and the odd sampled signal words and their error correction words are delayed by a fixed time C.

After that, the error detection encoder 52 uses a cyclic code (CR
C) is added to the modulator 54 and the rotary head 56.5.
8 and is recorded on the recording medium.

The recording signal recorded on the recording medium by the recording system is reproduced by the rotary heads 56 and 58, and the reproduced signal is demodulated into a digital signal by the demodulator 64, and the reproduced signal is converted into a digital signal by the error detection decoder 6.
Error detection is performed in step 6, and a dinterleave circuit 68 performs an operation completely opposite to that of interleave circuit 5, and returns the data string that generated the error correction word. Thereafter, the error correction decoder 70 corrects the correctable errors, and sends the uncorrectable errors to the correction circuit 74 as erasure information.

After that, in the memory circuit 72, the odd sample words or even sample words are stored in units of words in the same way as the memory circuit, and the analog-to-digital converter 14 of the recording system is also returned to the original time sequence outputted, and the lost information is stored. In some cases, average value interpolation is performed in the correction circuit 74 and sent to the output terminals 42L and 42R via the digital-to-analog converter 38 and the low-pass filter 4o.

Therefore, the block number N may be the length 2D+1 in the playback data.
If a no-stop error occurs, as mentioned above, the error correction code can only correct up to two errors even if erasure information is used. This can be understood from Figure 4. , among the block data of block numbers N, N10, and N+2D, An, Bn, An+2, Bn-30, A
n 10z-sD, Bn+2-3D, ------・,B
The n+4-tsD sampling words are corrections, but since these are even sampling words and not consecutive odd sampling words, the sampling words are not consecutively corrected and are within the average value. The generation of noise can be reduced by inserting the

In addition, as the delay time C in the interleave circuit 5o becomes thicker (the larger it is, the more average value interpolation can be performed), the length of the strike error increases. If you choose a larger value than
It is possible to configure an M recording/reproducing device.

Assuming that one code consists of M symbols in t76, in the above embodiment, one symbol is an odd number (an even number), but multiple samples are one symbol,
Alternatively, it is obvious that one sample may be divided into several parts and used as one symbol.

Further, in the above embodiment, the delay time C is constant, but the delay time may be set as C, C, . . . C for each symbol.

Furthermore, in the above embodiment, a PC equipped with a recording and reproducing system
Although the M recording and reproducing apparatus has been described, it goes without saying that the present invention can also be applied to a PCM recording apparatus or a PCM reproducing apparatus in which either the reproducing system or the recording system is omitted.

As described above, according to the present invention, by encoding in odd sample group and even sample group units and separating adjacent odd and even samples by interleaving, errors exceeding the error correction capability on the recording medium can be prevented. However, it is possible to perform correction processing such as average value interpolation, and has the excellent effect of providing a PCM recording and reproducing device with low noise and high reliability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional PCM recording and reproducing device.
Figure 2 is a data layout diagram, and Figure 3 is a PC according to the present invention.
FIG. 4 is a block diagram showing one embodiment of the M recording/reproducing apparatus, and is a data arrangement diagram thereof. The same members in each figure are given the same reference numerals, 46 is a memory circuit, 48 is an error correction encoder, 5o is an interleave circuit,
52 is an error detection encoder, 66 is an error detection decoder, 68 is a dinterleave circuit, 70 is an error correction decoder, 72 is a memory circuit, and 74 is a correction circuit. Agent: Masuo Oiwa, patent attorney (2 others)

Claims (1)

[Claims] (1) In a PCM recording and reproducing device that samples an audio signal, converts it into a digital signal, records it on a recording medium such as a magnetic tape, and reproduces it from the recording medium.
Error correction is performed on each of the odd sample group and the even sample group of the digital signal, and an encoding means for adding a code for error detection, etc., and a code including the odd sample group and the even sample group concatenated therewith. A recording system comprising an interleaving means for separating and interleaving the included code, a dinterleaving means for performing an operation opposite to the interleaving means, a decoding means for detecting or correcting an error, and a recording system for detecting or correcting an uncorrectable error. P
CM recording and playback equipment. (2. The PCM recording and reproducing apparatus according to claim 1, wherein the amount of separation between adjacent codes is selected to be larger than the amount by which each sample within the code is separated by interleaving.