JP2775788B2 - Data error detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Field of the Invention The present invention detects an error in reproduction output from a recording medium with respect to recording data double-recorded on a recording track on a recording medium by adding an error correction code. The data error detection apparatus is applied to, for example, a so-called D1 format or D2 format digital video tape recorder in which digital audio data is double-recorded on a recording track.

B. Summary of the Invention The present invention relates to recording data that is double-recorded on a recording track on a recording medium by adding an error correction code to each reproduction output reproduced from the recording track on the recording medium. Performs correction decoding processing using the inner code, compares each of the reproduction data subjected to the correction decoding processing, and outputs an error detection output when each of the reproduction data subjected to the correction decoding processing has no error and does not match. By doing so, data errors can be detected with a simple configuration.

2. Description of the Related Art Conventionally, in a so-called D1 format or D2 format digital video tape recorder, video data and audio data digitized by a rotary magnetic head device (RH) as shown in FIG. As shown in the figure, recording is sequentially performed on recording tracks (T) inclined with respect to the longitudinal direction of the magnetic tape (10).

That is, the rotating magnetic head device (RH) shown in FIG.
Is a pair of print heads (A ₁ ), (B ₁ ), (A ₂ ), (B ₂ ) arranged 180 ° opposite to each other, and the print heads (A ₁ ), (B ₁ ), (B ₁ ) A pair of 180 ° facing read heads (C ₁ ) arranged in a direction orthogonal to A ₂ ) and (B ₂ )
(D ₁ ), (C ₂ ), (D ₂ ), and the recording heads (A ₁ ), (B ₁ ), (A ₂ ), (B ₂ ) and the reproducing head (C ₁ ) of each pair described above. ) · (D ₁ ), (C ₂ ) · (D ₂ ) are arranged with different heights by one track width. In the case of, for example, the NTSC system, the rotary magnetic head device (RH) is driven at a rotation speed of 1.5 rotations per field, and as shown in FIG. ) Upper three sets of trucks (T ₁ ) ~
Record at (T ₃ ).

Each of the above track of the magnetic tape (10), a central portion thereof fields _{(F 1) · (F 2} ) ... video data (V in
_{11), (V 12),} (V 13) · (V 21), (V 22), (V 23)
.. Are recorded as video areas, and audio data (A ₁₁ ), (A ₁₂ ),
_{(A 13) · (A 21} ), is provided with _{(A 22), (A 23} ) ... of the double recording is the speech region.

In a digital video tape recorder of such a format, the recording heads (A ₁ ), (B ₁ ), (A ₂ ), (B ₂ ) simultaneously record video data and audio data while simultaneously reproducing the reproduction head (C ₁ ). Since the same track can be reproduced by (D ₁ ), (C ₂ ) and (D ₂ ), conventionally, for example, the recording head (A ₁ ) The data recorded by (B ₁ ), (A ₂ ), (B ₂ ) and the data reproduced by the reproducing heads (C ₁ ), (D ₁ ), (C ₂ ), (D ₂ ) So-called Verify (Verify)
A function is added to confirm whether or not the recording has been performed normally.

That is, in the conventional recording / reproducing system shown in FIG. 4, the analog input signal S _IN is a sample-and-hold (S /
H) An encoder (3) which is supplied to an analog / digital (A / D) converter (2) through a circuit (1) and is digitized by the A / D converter (2) as recording data D _REC.
And the recording data D _REC is _supplied to a data comparator (5) via a delay circuit (4).
After the encoder (3) performs predetermined data processing such as data shuffling and addition of an outer code and an inner code for error correction, each recording head (A ₁ ) of the rotary magnetic head device (RH) is processed. ) · (B ₁ ), (A ₂ ), (B ₂ ) are recorded on each track (T ₁ ) to (T ₃ ) on the magnetic tape (10).

The recording / reproducing system performs a reproducing operation on each of the tracks (T ₁ ) to (T ₃ ) simultaneously with the above-mentioned recording operation, and the reproducing heads (C ₁ ), (D ₁ ), (C ₂ ), ( With respect to the reproduction output by D ₂ ), the decoder (6) performs predetermined data processing corresponding to the encoder (3) to thereby record data D _REC recorded on each of the tracks (T ₁ ) to (T ₃ ).
To obtain reproduced data D _PB for this reproduction data D _PB is adapted to be supplied to the data comparison circuit (5).

Here, the delay circuit (4) sets the delay amount equal to the time required to obtain the reproduction data D _PB for the recording data D _REC recorded on each of the tracks (T ₁ ) to (T ₃ ) to the recording data D Give to _REC .

Then, the recording data D _REC given via the delay circuit (4) and the reproduced data D _PB are compared by the data comparing circuit (5) to detect a mismatching portion, so that occurrence of a recording error is prevented. A counter (11) counts the detection error detection output of the data comparison circuit (5) and issues a warning when the number of recording errors exceeds a predetermined number.

D Problems to be Solved by the Invention By the way, like the conventional recording / reproducing system shown in FIG. 4, the recording data D _REC given via the delay circuit (4) and the reproduced data D _PB The occurrence of a recording error is detected by detecting a non-coincidence portion by the data comparison circuit (5), and the recording error detection output by the data comparison circuit (5) is counted by a counter (11), and a recording error is detected. If a warning is issued when the number of occurrences exceeds a predetermined number, for example, when new data is overwritten and recorded on a recorded magnetic tape (10) by so-called insert editing, etc. If the previous data remains in the section, the data comparison circuit (5) detects it as a recording error. If the number of recording errors is small and does not reach the predetermined number, a warning is issued. Is not, the previous data of the unerased portions is disadvantageously would be reproduced commingled new data.

Accordingly, the present invention has been made in view of the above-described conventional circumstances, and provides a data error detecting device capable of reliably detecting a data error due to a remaining erase of previous data on a recorded magnetic tape. The purpose is.

E Means for Solving the Problems In order to achieve the above object, a data error detection device according to the present invention provides an error correction code to a recording track on a recording medium, Correction decoding processing by an inner code is applied to each reproduction output reproduced twice from the recording track on the recording medium by the correction decoding processing means, and each of the reproductions having been subjected to the correction decoding processing by the mismatch detecting means. Data is compared, and an error detection output is output when the reproduced data subjected to the correction decoding processing do not coincide with each other in an error-free state.

F Function In the data error detection device according to the present invention, the correction decoding processing means adds an error correction code to a recording track on the recording medium, and outputs each reproduced output of the double-recorded recording data using an inner code. A correction decoding process is performed.
Then, the discrepancy detecting means compares each of the corrected and decoded reproduction data, and when each of the corrected and decoded reproduction data does not match in an error-free state, that is, on the recorded magnetic tape, An error detection output indicating data due to the remaining remaining data is erased.

G. Embodiment Hereinafter, an embodiment of the data error detection device according to the present invention will be described in detail with reference to the drawings.

In the embodiment shown in the block diagram of FIG. 1, the present invention is applied to the audio signal reproduction system of the digital video tape recorder having the track format shown in FIG.

In this embodiment, among the reproduction outputs reproduced from the respective tracks on the magnetic tape (10) having the track format shown in FIG. 3, the reproduction output from the audio area on the entrance side of the video area (hereinafter, referred to as the output). The first audio reproduction output is supplied to a first correction decoding processing circuit (21) via a first input terminal (20A), and the reproduction output from the audio area on the exit side of the video area is output. (Hereinafter, referred to as a second audio reproduction output) is supplied to a second correction decoding processing circuit (22) via a second input terminal (20B).

The correction / decoding processing circuits (21) and (22) perform a correction decoding process such as an error correction process or a decoding process on each of the audio reproduction outputs on a data block basis of the inner code. The decoded audio reproduction data DATA ₁ and DATA ₂ are converted into error flags EF ₁ and EF _{2 respectively.}
It is output together with. The audio decoding data DATA ₁ and DATA _{2 which} have been subjected to the correction decoding processing obtained by the correction decoding processing circuits (21) and (22) are supplied to a data comparator (30) and selected switch (23). To the third correction decoding processing circuit (24).
The error flag EF ₁ obtained in the first correction decoding processing circuit (21), the audio reproduction data DATA ₁ correction decoding processed indicates absence of error at logic "H", the It is supplied to one AND gate (31) and a first burst error detection circuit (32). Further, the error flag EF obtained by the second correction decoding processing circuit (22)
₂ indicates a state in which there is no error in the audio reproduction data DATA ₂ which has been subjected to the correction decoding processing by logic “H”.
The signal is supplied to a gate (31) and a second error detection circuit in a burst (33).

The third correction / decoding processing circuit (24) subjects the audio reproduction data supplied via the selection switch (23) to a correction decoding process such as an error correction process using an outer code or a decoding process. The audio reproduction data which has been subjected to the correction decoding processing by the third correction decoding processing circuit (24) is supplied to a D / A conversion circuit (26) via a muting processing circuit (25), and the D / A conversion circuit The signal is converted into an analog signal by the conversion circuit (28) and output from the signal output terminal (27) as a reproduced audio signal.

The data comparator (30) compares each of the corrected and decoded audio reproduction data DATA ₁ and DATA ₂ obtained by each of the correction and decoding processing circuits (21) and (22). Is supplied to the first AND gate (31). This first AND
When the error flags EF ₁ and EF ₂ are both at logic “H”, that is, when the error decoding processing circuits (21) and (22) have already performed the correction decoding processing, the gate (31) performs the processing. It is opened when both the audio reproduction data DATA ₁ and DATA ₂ have no error, and outputs the mismatch detection output by the data comparator (30) as an error detection output.

Here, when the data remaining on the recorded magnetic tape (10) due to the erasure of the previous data is normally reproduced by one of the correction / decoding processing circuits (21) and (22). Is the audio data DA obtained by the correction decoding processing circuits (21) and (22) and having undergone the correction decoding processing.
Since both TA ₁ and DATA ₂ do not match in an error-free state, an error detection output indicating a data error due to the unerased residue can be obtained by the first AND gate (31).

The data remaining on the recorded magnetic tape (10) due to the erasure of the previous data is reproduced in both the corrective decoding processing circuits (21) and (22) in a regular and identical manner. The probability is extremely low, and in practice, each of the corrected and decoded audio reproduction data DATA ₁ and DATA ₂ obtained by each of the correction and decoding processing circuits (21) and (22) does not match in an error-free state. , It is possible to sufficiently detect a data error due to the unerased data.

In this embodiment, the first AND gate (3
The error detection output obtained in 1) is supplied as a control signal to the muting processing circuit (25) through a second AND gate (35), and when a data error due to the unerased residue occurs, the reproduced audio signal is muted. I'm trying to put on

Here, when a data error due to the above-mentioned unerased data occurs, a burst error always occurs before and after the data error. Therefore, in this embodiment, each of the burst error detection circuits (32) and (33) performs Audio playback data DATA ₁ ,
For DATA ₂ , the occurrence of a burst error is detected for each segment. Then, the detection output of the first burst error detection circuit (32) is supplied as a selection control signal to the control input terminal of the selection switch (23). Select the audio playback data of. Further, each detection output of each of the burst error detection circuits (32) and (33) is supplied to the second AND gate (35) as a gate control signal through an exclusive OR gate (24), and the respective audio signals are output. Playback data DATA
Only when a burst error occurs in only _{one of the first} and _second data, the third OR gate (24) outputs the third signal.
Is opened to allow muting by the error detection output.

H In the data error detection device according to the present invention, the error correction code is added to the recording track on the recording medium, and each reproduction output of the recording data that is double-recorded is corrected by the correction decoding processing means. A correction decoding process using a code is performed. Then, the discrepancy detecting means for comparing each piece of reproduction data which has been subjected to the correction decoding processing by the correction decoding processing means reproduces each reproduction data in an error-free state by the correction decoding processing by the correction decoding processing means. In addition, when there is a mismatch, that is, when an erasure remaining portion of the previous data by insert editing or the like is normally reproduced by the correction decoding processing means, an error detection output is output.

Therefore, by applying the present invention, for example, in a digital video tape recorder or the like for recording and reproducing digital data in a so-called D1 format or D2 format in which digital audio data is double-recorded on a recording track, etc. It is possible to easily and surely detect a data error due to the remaining data erased before the tape occurs due to so-called insert editing or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a data error detection device according to the present invention. FIG. 2 is a schematic diagram showing a configuration example of a rotary magnetic head device used for a digital video tape recorder, and FIG. 3 is a schematic diagram showing a track format of a digital video tape recorder using the rotary magnetic head device. FIG. 4 is a block diagram showing a configuration of a recording and reproducing system of a conventional digital video tape recorder having a recording confirmation function. (21), (22): Correction decoding circuit (30): Data comparator (31): AND gate

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G11B 20/18 576 G11B 20/18 576F

Claims (1)

(57) [Claims] An error correction code is added to a recording track on a recording medium, and double-recorded recording data is reproduced twice from the recording track on the recording medium by a correction decoding processing means. Each of the reproduced outputs is subjected to correction decoding processing using an inner code, and each of the reproduction data subjected to the correction decoding processing is compared by the mismatch detecting means. A data error detection device that outputs an error detection output when there is a mismatch.