JPS6376155A - Data error display device - Google Patents

Abstract

PURPOSE:To easily decide the good condition and adverse condition of a reproducing type device such as the quality or damaged condition of a magnetic tape and the clogging of a reproducing head by being provided with a data error detecting means to detect a data error and a data error display means connected to the next step of the data error display means. CONSTITUTION:The data error display device is provided with a data error detecting means 3 to detect the data error of a data reproducing device having a rotary head 1 and a data error display means 4 connected to the next step of the data error detecting means 3. When a track on a magnetic tape is alternately scanned by two heads, one side head generates the clogging and the signal of the head to be inherently reproduced is omitted, and when the track on the magnetic tape is alternately scanned by two heads, a part of the signal reproduced by respective heads is omitted, concretely, the edge part of the magnetic tape is damaged, the data error detecting means 3 detects the drop-out and the data error display means 4 displays the effect.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention relates to a data error display device, and particularly to one that displays data errors caused by dropouts.

[Conventional technology]

In general, in recording methods that use magnetic recording media such as magnetic tape, dropouts occur when the recorded signal is lost during playback due to non-uniformity of the coated magnetic material or dust particles adhering to the surface. It is known to be easy.

This phenomenon does not occur in analog magnetic recording and reproducing devices such as VTRs because the output level simply drops momentarily, but in digital audio tape recorders (hereinafter abbreviated as DAT), etc. In digital magnetic recording and reproducing devices, this causes bit errors and noise generation.

[Problem that the invention seeks to solve]

However, in conventional magnetic recording and reproducing devices, there is no way to know whether or not this dropout has occurred.
It is difficult to judge the quality or damage of the magnetic tape, or the performance of the reproduction system, such as clogging of the reproduction head.

The present invention has been made in view of the above-mentioned problems, and its technical object is to provide a data error display device that can detect and display data errors associated with dropouts.

[Means for solving problems]

In order to solve the above technical problem, the present invention has the following configuration.

That is, the data error display device includes data error detection means for detecting data errors in a data reproducing device having a rotary head, and data error display means connected to the next stage of the data error detection means.

Further, the data error detection means may include a data error amount detection section for detecting the amount of data errors and a configuration configured to display the amount of data errors.

[Effect]

When two heads alternately scan tracks on a magnetic tape, one head becomes clogged and the signal from the head that should have been reproduced is lost. When a part of the signal reproduced by each head is missing during scanning, specifically when the edge of the magnetic tape is damaged, the data error detection means detects the dropout, and the data error display means to indicate that.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

The DAT 2 as a data reproducing device is provided with a rotary head 1 having a head A and a head B, and this rotary head 1 includes a data error detection means 3 for detecting a data error by 1, and a data error detection means 3 for detecting a data error by 1, and a Data error display means 4 connected to the stage are provided. Also,
A reproduction circuit 5 is connected to the data error detection means 3.

The data error detection means 3 includes a reproduction amplifier 10 connected to the rotary head l, a reproduction stage 11 connected to the next stage of the reproduction amplifier 10 and extracting data by clock reproduction, and demodulating the data reproduced by the reproduction stage 11. demodulation stage 1
2. It includes a synchronous address detection stage 13 that detects the synchronous address of the signal from this demodulation stage 12, and the signal from this synchronous address detection stage 13 is divided into an error detection and correction stage 14 and sent to a correction output stage 15 and a sampling stage 16. It is becoming more and more human-powered.

The error detection and correction stage 14 outputs an error flag (a flag that is set when an error occurs) output signal to the sampling stage 16 side.

A DA converter 23 is connected to the next stage of the correction output stage 15, and passes through a low-pass filter (not shown) to an audio output stage.

On the other hand, the output signal of the sampling stage 16 is input to a first frequency divider 17. The first frequency divider 17 is also configured to receive the signal from the regeneration stage 11, and the output signal from this is input to the second frequency divider 19, which then determines the pulse width and timing. Timing detection stage 2 detects
It is input to 0.

Separately, the output signal of the sampling stage 16 is input to a comparator 18 that performs counting and comparison, and the output signal from the comparator 18 is input to the timing detection stage 2°.

The data error display means 4 is connected to the next stage of the timing detection stage 20. This data error display means 4 includes a first display section 21 that displays damage to the magnetic tape, and a second display section 22 that displays clogging of the rotary head l.
It consists of

In the present invention, the DAT recording pattern is as shown in FIG.
L oddSReven recorded by head A.

This method takes advantage of the fact that the data is divided into four blocks, Rod, and Even, which are recorded by head B, and these four blocks are independently corrected for errors.An example of the operation will be described below together with the configuration of the timing detection stage 20.

The output signal from the comparator 18 is first sent to the shift register 30.
When 8 bits of data are input, the timing signal from the clock 42 inputs the data as a parallel bit string to the comparator 31 at the next stage.

Reference data 32 is input to this comparator 31, and is compared with the data from the shift register 30, and if they match, the count of the next stage counter 33a is incremented by one. If the two data do not match in the comparator 31, the data from the shift register 30 is input to the comparator 32, where it is compared with reference data 33.

If these match, the count of the counter 33 at the next stage is incremented by one.

On the other hand, the data from the shift register 30 is transferred to the comparator 3.
4 is also input at the same time, and here reference data 35
compared to If these match, the next stage counter 36
However, if the two data do not match in the comparator 34, the data from the shift register 30 is input to the comparator 37, where it is compared with the reference data 38.

If these data match, the count of the next stage counter 36 is incremented by one, but if the two data do not match,
The data from the shift register 30 is input to a comparator 39, where it is compared with reference data 40, and if they match, the count of the counter 36 at the next stage is incremented by one.

A data error display means 4 is connected to the rear stage of these counters, and a first display section 21 displays damage to the magnetic tape when a certain number or more is counted per unit time.
Alternatively, the second display unit 22, which displays the clogging of the rotary head l, is turned on, and the above operation is repeated.

Specifically, the reference data 32 to 40 are as follows:
00001100.11000000.0100010
It is set to 0.10001000.11001100.

Among these 8-bit number sequences, 00001100, Ift
)00000.11001100, as shown in FIG.
This shows the reproduced signal in a state where the signal of head B (indicated by the dotted line) that should originally be reproduced is missing when the head B becomes clogged.

On the other hand, 01000100.10001000 is the second
As shown in Figure (B), when heads A and B alternately scan tracks on a magnetic tape, a portion of the signal reproduced by each head AB is missing, specifically at the edge of the magnetic tape. This shows the reproduced signal when the part is damaged.

Therefore, the reproduced signal is used as the reference data 32 to
40 and if there is a match, this means that dropout has occurred on the matching side.

FIG. 4 shows the contact timing of the rotary head to the magnetic tape and the reproduced output waveform. FIG. 4 (A) shows the contact timing of the rotary head to the magnetic tape, and FIG. 4 (B) shows the contact timing of the rotary head to the magnetic tape.
4(C) shows a state in which the head B is clogged, and FIG. 4(D) shows a state in which the end of the magnetic tape is damaged.

Note that if the end of the magnetic tape is damaged, the width of the pulse output from the timing detection stage 20 will vary depending on the state of damage, so the data error display means 4 will continuously display this pulse width. This is possible by displaying the information.

In this case, it becomes clear which part of the magnetic tape is damaged.

〔Effect of the invention〕

According to the present invention, it is possible to detect and display data errors associated with dropouts, so it is possible to determine the quality or damage of the magnetic tape, etc., and the performance of the playback system such as clogging of the playback head. This makes it easier.

Therefore, in response to this display, measures such as replacing the magnetic tape or cleaning the magnetic head can be taken, and the data reproducing apparatus can be maintained in perfect condition.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a block diagram, FIG. 2 is a waveform diagram, FIG. 3 is a plan view showing the state of data recording on a magnetic tape, and FIG. 4 is a diagram showing the situation in which data errors occur. The waveform diagram shown in FIG. 5 is a block diagram of a partial circuit. 1... Rotating head, 2... Digital tape recorder as a data reproducing device, 3... Data error detection means, 4... Data error display means, 5... Data error amount detection section. Utility model registration applicant Pioneer Corporation Figure 1 Figure 2

Claims (2)

[Claims] (1) Data error detection means for detecting data errors in a data reproducing device having a rotating head, and data error display means connected to the next stage of the data error detection means. Display device. (2) The data error detection means includes a data error detection means for detecting data errors in a data reproducing device having a rotary head, and a data error display means connected to the next stage of the data error detection means. A data error display device characterized by being provided with a data error amount detection section for detecting an error amount and displaying the data error amount.