JPH01312798A - Digital recording and reproducing device - Google Patents

Abstract

PURPOSE:To easily and surely attain the propriety check of a recording medium and a recording and reproducing function with small size and light weight by providing a reproducing means reproducing a specific code block of a digital signal, a quality evaluation means evaluating the quality of the specific code block and a display means displaying the evaluation result. CONSTITUTION:A digital video signal reproduced from the final track on a magnetic tape 3 by a magnetic head 2 is subjected to code information at a reproducing circuit 4 and fed to a quality evaluation means 5. The quality evaluation means 5 has a code error detection circuit which compares the discriminating value of the occurrence state of code error with a preset prescribed value. If there is dirt on the magnetic head 2 or choking exists thereupon, since the S/N of a reproducing signal is deteriorated, a code error detection circuit of the quality evaluation means 5 detects much code error than the setting value and supplies the result to a display means 6. Thus, the recording and reproducing head for an information signal is used to check the recording and reproducing function and the small sized, light weight device is realized with low power consumption.

Description

[Detailed description of the invention] [Industrial application field] The present invention digitizes and records information signals.

Particularly related to digital recording and reproducing devices.

The present invention relates to a digital recording/reproducing apparatus equipped with a test device for checking the quality of a recording/reproducing function and checking the quality of a recording medium.

[Prior Art] In magnetic recording and reproducing devices such as video tape recorders (hereinafter referred to as VTRs), if the magnetic head is dirty or clogged, or if the magnetic tape is worn out and becomes defective, Signal recording and reproduction are not performed well, and the S/N of the reproduced signal is significantly degraded. This condition usually becomes apparent only after recording and playback, and this often results in the recording of the desired information signal becoming unusable. .

Therefore, for commercial VTRs, for example, in Masumi Harada, "Common sense of modern people, Introduction to new video technology, chapter 18", published by Dempa Shimbunsha, ρ, 191, in addition to the recording/playback head on the head cylinder, there is also a playback head. A dedicated head is provided,
A technique has been disclosed in which, in a recording mode, a track recorded by a recording/reproducing head is simultaneously reproduced and scanned by a reproduction-only head, and the recording state is monitored. According to this, the monitor screen can be used to determine whether the recording state is good or bad.

[Problem to be Solved by the Invention] However, in the above-mentioned conventional technology, since the check of the quality of the recording state is carried out using a read-only head provided separately from the recording/playback head, this read-only head is Even if the recording/reproducing head becomes dirty or clogged, the same effect will appear in the check results as when the recording/reproducing head is dirty, clogged, or the tape is defective. For this reason, even though the recording condition is good, it is erroneously determined to be defective.

In addition, VTRs can be integrated with video cameras, etc.
There is a trend toward smaller size and lighter weight for easier portability, and for this reason, there is also a trend toward smaller diameter head cylinders. Providing a reproduction-only head for monitoring the recording state on this small-diameter head cylinder poses a problem in terms of installation space.

In addition, a circuit for simultaneous playback monitoring is also required, and V
There is a problem that the circuit scale of the TR increases. In particular, VTRs that record and reproduce digital information signals
In order to prevent a significant expansion of the frequency band of the recording signal, the recording signal is divided into multiple channels, and each channel is recorded and reproduced using a separate magnetic head. For this reason, the head cylinder must be provided with a large number of magnetic heads for each channel, and if a read-only head is also provided for monitoring the recording state, this is also provided for each channel. Therefore, it is not possible to reduce the diameter and size of the head cylinder.

Furthermore, when a digital recording VTR is equipped with a playback-only head to monitor the recording status, a high-speed, large-scale signal processing circuit such as an error correction circuit is required to process the playback signal, which requires a large amount of circuit space. There is also the problem of increased power consumption.

The object of the present invention is to solve such problems and to reduce the size.

It is an object of the present invention to provide a digital recording and reproducing device that is lightweight and allows easy and reliable recording and reproducing functions and checking the quality of a recording medium.

[Means for Solving the Problems] In order to achieve the above object, the present invention reproduces a specific code block of the digital signal recorded at a predetermined position on the recording medium at the end of recording of the desired digital signal. A reproduction means, a quality evaluation means for evaluating the quality of the specific code block, and a display means for displaying the evaluation result by the quality evaluation means are provided. The quality evaluation is stored in memory when the specific code block is recorded.

This is done by comparison with the particular code block read from the memory.

The present invention also provides a pattern generating means for generating a digital code block of a predetermined pattern, a recording means and a reproducing means based on a command signal to record the digital code block on a recording medium, and then to reproduce the digital code block. A control means for controlling the digital code block, a quality evaluation means for evaluating the quality of the reproduced digital code block, and a display means for displaying the evaluation result by the quality evaluation means.

Furthermore, the present invention provides pattern generating means for generating digital code blocks representing a predetermined image pattern;
A control means for controlling the recording means and the reproduction means based on a command signal to record the digital code block on the recording medium and then reproduce it; and a conversion means for converting the reproduced digital code block into an analog video signal. and a display means to which the analog video signal is supplied and displays an image.

[Operation] To check the recording/reproducing function for clogging or dirt on the magnetic head, deterioration of the magnetic tape, etc., record the desired signal on the recording medium, reproduce it, and check the S/N of the reproduced signal and the degree of dropout. This can be done by detecting.

In the present invention, a digital signal is used to check the recording and reproducing function, and the check is performed by evaluating the quality of the signal based on code errors. This code error is extremely sensitive to recording and reproducing performance, and is also noticeable due to dropouts caused by the magnetic tape, so checking of recording and reproducing functions is performed with high precision.

Also, the check signal for checking the recording/reproducing function is a code block of a video signal such as a program or a video taken by a camera, or a code block of a predetermined pattern or a predetermined image pattern generated from a pattern generating means. Since the signal is recorded and then played back and processed for quality evaluation (that is, recording and playback are not simultaneous), it is possible to record and play back this check signal using a normal recording/playback head. can.

Therefore, a head dedicated to reproducing the check signal and a circuit for processing the reproduced signal are not required, and the head cylinder can be made smaller and lighter, and the circuit scale can be reduced.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a digital recording and reproducing apparatus according to the present invention, in which 1 is a recording circuit, 2 is a magnetic head, 3 is a magnetic tape, 4 is a reproduction circuit, 5 is a quality evaluation means, and 6 7 is a display means, 7 is a control means, and 8 is a drive device. Although the present invention will be explained here as a helical scan digital recording type VTR, the present invention can be applied to digital recording/reproducing devices in general.

In the figure, in the recording mode, a drive device 8 drives a head cylinder (not shown) to which a magnetic head 2 is attached and a magnetic tape 3 under the control of a control means 7. In the recording circuit 1, a digitized video signal (
An error detection and correction code is added to each predetermined portion of the digital video signal (hereinafter referred to as a digital video signal), and the error detection and correction code is added to each predetermined portion.
Recorded as a book track.

When the recording mode ends by operating the stop button, etc.
Under the control of the control means 7, the drive device 8 drives the magnetic tape 3.
is rewound, the magnetic head 2 is made to search and reproduce the last recorded track (last trunk) on the magnetic tape 3 using the track address, and then the magnetic tape 3 is stopped. At this time, the head cylinder may also be stopped.

The digital video signal reproduced from the last track on the magnetic tape 3 by the magnetic head 2 is code-identified by the reproduction circuit 4 and then supplied to the quality evaluation means 5. The quality evaluation means 5 has a code error detection circuit, and the reproduction circuit 4
A code error in one track of the digital video signal supplied from the digital video signal is detected, and the occurrence status of the code error is compared with a predetermined value (hereinafter referred to as a set value) set in advance as a determination value. Here, if the magnetic head 2 is dirty or clogged, the S/
Since N has deteriorated, the code error detection circuit of the quality evaluation means 5 detects more code errors than the set value. Also,
If the magnetic tape 3 has deteriorated due to wear and tear, dropouts will increase and a continuous stream longer than the set value will
ms (burst errors) are detected, or a large number of such burst errors are detected. The quality evaluation means 5 checks the reproduced signal for this reason and supplies the result of the check to the display means 6. The display means 6 displays the result of the check, for example, ``Increase in errors,'' or displays a warning such as ``Head cleaning required'' or ``Defective tape,'' and informs the user of the check result of the recording/playback function. Let me know.

According to this, after recording a program or camera shooting,
It becomes possible to check the recording/playback function.

In this case, if the magnetic head is dirty or clogged or the magnetic tape is deteriorated, the S/N of recorded programs or scenes captured by the camera will deteriorate during playback. Appropriate measures can be taken to ensure good recording and playback from the next time onwards. It is also possible to set the recording mode for a short time before recording a program or scene, thereby checking the recording and reproducing function.

As described above, in this embodiment, it is possible to check the recording and playback function without adding a playback-only head or a full playback signal processing circuit, and it is possible to reduce the size and weight of portable VTRs and camera-integrated VTRs. , is effective in reducing power consumption.

FIG. 2 is a block diagram showing a specific example of the quality evaluation circuit 5 in FIG. 1, in which 9 is a digital signal processing circuit;
10 is a memory, 11 is a comparison circuit, 12 is a counter, 13
1 is a discrimination circuit, and parts corresponding to those in FIG. 1 are given the same reference numerals.

In this specific example, a bit comparison method is used for the code error detection circuit of the quality evaluation means 5, and in FIG. 2, the comparison circuit 11 and the counter 12 constitute the code error detection circuit.

The recording circuit 1 is provided with a memory 10 . This memory 1
0 has a storage capacity that is greater than the data amount of one track's worth of code blocks formed on the magnetic tape 3. In the recording mode, a digital video signal from the digital signal processing circuit 9 is written into the memory 1o by a write pulse φ8, and is read out in code block units from the memory 1o by a read pulse φR in synchronization with the scanning timing of the magnetic tape 3 of the magnetic head 2. It will be done. The digital video signal read from the memory 10 is supplied to the magnetic head 2 and recorded on the magnetic tape 3 one code block per track.

Here, in the memory 10, new code blocks are written while the stored code blocks are being erased.

When the recording mode ends, writing to the memory 1o is stopped, so that the same code block as that of the last track formed on the magnetic tape 3 remains stored in the memory 10.

Next, a search is made for the final track on the magnetic tape 3, and the code block of the digital video signal reproduced from this final track by the magnetic head 2 is sent to the reproduction circuit 4.
The signal is identified by code and supplied to the comparison circuit 11 of the quality evaluation means 5. At the same time, a code block having the same content as the code block recorded on the last track is read from the memory 10 of the recording circuit 1 and supplied to the comparison circuit 11. The comparison circuit 11 is composed of, for example, Ex-○R agate,
The code block output from the reproduction circuit 4 and the code block read from the memory 10 are compared bit by bit,
When the two bits are different, the pulse is sent to the counter 12.
Output to. The counter 12 is reset before the reproducing circuit 4 starts reproducing the code block of the final track.
The pulses supplied from the comparison circuit 11 are counted. When the playback of the last track is finished, the count value of the counter 12 is 1.
This is the number of code errors that occurred in the reproduced code block for the track, and the number of errors detected by this counter 12 is counted by the discriminating circuit 13.
and is compared with a preset set value S. The determination circuit 13 sends an output signal indicating whether or not the number of detection errors N is less than or equal to the set value S to the display means 6 as an evaluation result, and the result of the recording/reproduction function check is displayed.

As described above, in this embodiment, since the bit comparison circuit 11 is used as the code error detection circuit, the circuit scale can be made very small. Note that in a normal digital recording VTR, since digital video signals are recorded through a memory, this memory can be used as the memory 10 for data comparison. Further, the comparison circuit 11 may perform the comparison in units of symbols or units of blocks.

FIG. 3 is a block diagram showing another specific example of the quality evaluation means 5 in FIG.
is a digital comparator, and parts corresponding to those in FIG. 2 are given the same reference numerals.

In the figure, the reproduced code block from the reproducing circuit 4 and the code block read from the memory 10 are connected to the comparator circuit 1.
1' is input. Similar to the comparison circuit 11 in FIG. 2, the comparison circuit 11' is composed of, for example, an Ex-OR gate, and compares two input signals in units of words (bits may also be used) to ensure that they match. and error-free terminal E, and error-mismatch terminal E. A pulse is output for each. Pulses output from the error terminal E0 or the no error terminal E of the comparator circuit 11' are input as a count pulse and a reset pulse to the count terminal C8 and reset terminal C2 of the counter 12', respectively. Therefore, the counter 12' counts up only when there are continuous errors (burst errors). This counter 1
The count value A of 2' is supplied to the latch circuit 14 and the comparator 15, and the output B of the latch circuit #t14 is also supplied to the comparator 15. The comparator 15 compares the count value A of the counter 12' and the output B of the latch circuit 14, and when the count value A becomes larger than the output value B of the latch circuit 14, it outputs a latch pulse and outputs the count value A of the counter 12'. is latched in the latch circuit 14. In this way, after the code block of one track is reproduced, a value representing the length of the maximum flame burst error is latched in the latch circuit 14, and this is supplied to the discriminating circuit 13' to set the value S. ', and an evaluation result is output as to whether or not the length of this burst error is less than or equal to the set value S'.

According to this specific example, if the magnetic head is clogged or dirty, errors will occur continuously.
This can be detected, and even if the magnetic tape deteriorates, large burst errors will occur, so this can also be detected.

Although not shown, it goes without saying that the counter 12' and the latch circuit 14 are reset immediately before starting reproduction of the final track on the magnetic tape.

In addition, when the comparison circuit 11' compares in units of words, 1
If there is even one error in a word, this word is determined to be an error and an error terminal E is sent. A pulse is output from. This allows burst errors to be detected. On the other hand, when comparing bit by bit, 71'' bit is II
If the OI+ bit is mistaken, it will be detected as an error, but even if the "0" bit is mistaken, it will become a "0" bit and no error will be detected. For this reason, even if there is a burst error.

This burst error may be interrupted and the correct burst error length may not be detected. This problem does not occur when comparing word by word, but in order to eliminate this problem when comparing bit by bit, for example, when a bit error is detected, There is a method in which a pulse is output from the error terminal E of the comparator circuit 11' for a few moments, so that discontinuous portions during burst errors are made continuous.

FIG. 4 is a block diagram showing still another specific example of the quality evaluation means 5 in FIG. 1, and parts corresponding to those in the previous drawings are given the same reference numerals.

In the figure, the count value A of the counter 12' is
3'. In the discrimination circuit 13'', the counter 12
Every time the count value A of ' exceeds the predetermined set value S'
When the counter 12' becomes "High" level and the counter 12' is reset, it outputs a signal that becomes "Low" level. This output signal is supplied to the counter 12. The count value N of this counter 12 is sent to the discrimination circuit 13'. This is the number of burst errors with a length equal to or longer than the set value S' supplied.The counted value N of this counter 13' is compared with the set value S in the discrimination circuit 13, and if this counted value N becomes equal to or greater than the set value S, , a signal is output from the discrimination circuit 13.Thereby, deterioration of the magnetic tape can be checked based on the number of burst errors of a predetermined length or longer.

FIG. 5 is a block diagram showing still another specific example of the quality evaluation means 5 in FIG. 1, in which 16 is an error length measurement circuit, 17 is a determination circuit, and FIG.

Parts corresponding to those in FIG. 3 are given the same reference numerals.

In this specific example, the quality evaluation means 5 checks the recording/reproducing function using two methods: one using the specific example shown in FIG. 2, and the other using the specific example shown in FIG. be.

Similar to the specific example of FIG. 3, the comparison port g11' is used to check whether the code block from the memory 10 (FIG. 2) matches the reproduced code block, and the error terminal E is checked. The pulses from the no-error terminal E are supplied to the counter 12 and the error length measuring circuit 16, and the pulses from the no-error terminal E are supplied to the error length measuring circuit 16, respectively. The counter 12 counts the number of code errors, as in the specific example of FIG. 2, and the discrimination circuit 13 compares it with a set value and evaluates it as the number of random errors. - way,
The error length measuring circuit 16 includes the counter 12' in FIG.
Latch circuit 14. This circuit measures the maximum length of a burst error, which can be configured by the comparator 15, and obtains a measurement result representing the length of the maximum burst error in a code block for one track. This measurement result is supplied to the discrimination circuit 13' and evaluated in the same manner as in the specific example shown in FIG. The evaluation results of the discrimination circuits 13 and 13' are both supplied to the judgment circuit 17, where it is determined that if the burst l4J is short and the number of code errors is large, the magnetic head is contaminated, and if the burst error is long and the number of code errors is small, the magnetic head is contaminated. If the tape is deteriorated, the burst error is long, and the number of code errors is large, it is determined that the magnetic head is clogged, and a warning message is displayed on the display means 6.

FIG. 6 is a block diagram showing another embodiment of the digital recording/reproducing apparatus according to the present invention, in which 2' is a magnetic head;
8 is a switch, 19 is a head cylinder, and parts corresponding to those in FIG. 1 are given the same reference numerals.

In this embodiment, azimuth recording is performed using a plurality of magnetic heads. Here, an azimuth recording method in which two magnetic heads are used to perform recording or reproduction alternately will be described, but the same applies to an azimuth recording method using three or more magnetic heads.

In FIG. 6, in the recording mode, the digital video signal output from the recording circuit 1 is supplied to two magnetic heads 2.2' attached to the head cylinder 19, and the magnetic tape 3 is alternately recorded by '1 track'. recorded separately.

When the recording mode ends, the control means 7 controls the drive unit W8 to rewind the magnetic tape 3, and the magnetic heads 2, 2' scan and reproduce the last track by the magnetic heads 2, 2', respectively.

Next, the control means 7 stops the running of the magnetic tape 3 and, if necessary, also stops the rotation of the head cylinder 19.

The switch 16 is switched and controlled by the control means 7, and the switch 18 is switched in synchronization with the reproduction scanning of the magnetic tape 3 by the magnetic heads 2 and 2', and the digital video reproduced from the last track by the magnetic heads 2 and 2' is switched. The code block of the signal is passed through the switch 18 to the reproduction circuit 4.
supplied to

These code blocks are processed by a reproduction circuit 4, quality evaluated by a quality evaluation means 5, and the evaluation results are displayed on a display means 6.

FIG. 7 is a block diagram showing a specific example of the recording circuit 1 and the quality evaluation means 5 in FIG.
0'' is a memory, 20 is a switch, and parts corresponding to those in FIG. 2 are given the same reference numerals.

In the figure, memories 1o'' and 10'' each have a storage capacity greater than the data amount of a code block recorded on one track on the magnetic tape 3.

In the recording mode, the switch 20 is closed to the memory 10' side while the magnetic head 2 scans the magnetic tape 3 (FIG. 6).
A digital video signal is read from the memory 10', supplied to the magnetic head 2, and recorded on the magnetic tape 3. At this time, the digital signal processing circuit 9 is stored in the memory 10''.
A digital video signal from is written. Conversely, during the period when the magnetic head 2' (FIG. 6) scans the magnetic tape 3, the switch 20 is closed to the memory 10'' side, and the switch 20 is closed to the memory 10'' side.
A digital video signal is read from 0'' and supplied to the magnetic head 2', and a digital video signal from the digital signal processing circuit 9 is written into the memory 10'.

When the recording mode ends, writing to the memories 10' and 10'' is stopped, and the code block of the last track by the magnetic head 2 is stored in the memory 10', and the code block of the last track by the magnetic head 2'' is stored in the memory 10''. Retained. The reproduced code block from the last track by the magnetic head 2 is transferred from the reproducing circuit 4 to the comparing circuit 11.
When the signal is supplied to the memory 10', the switch 20 is closed to the memory 10' side and the memory 10' is read out, and the code block resulting from this reading is supplied to the comparator circuit 11. Further, when the reproduced code block from the last track is supplied to the comparator circuit 11 by the magnetic head 2', the switch 20 is closed to the memory 10'' side, and the read code block is supplied to the comparator circuit 11. The subsequent operation is similar to the specific example shown in Fig. 2.However, in this specific example, the quality evaluation is performed for the two final tracks, that is, the two tracks, and the set value S is also changed accordingly. Set.

It goes without saying that the quality evaluation means shown in FIGS. 3 to 5 can also be used in this embodiment.

FIG. 8 is a block diagram showing still another embodiment of the digital recording/reproducing apparatus according to the present invention.

2a and 2b are magnetic heads, 4a and 4b are playback circuits, and 5a
, 5b is a quality evaluation means, 6a and 6b are display means, 10a
, 10b is a memory, lla and llb are comparison circuits, 12a
, 12b is a counter, and 13a.

13b is a discrimination circuit, and parts corresponding to those in FIG. 6 are given the same reference numerals.

In this embodiment, multi-channel recording is performed using a plurality of magnetic heads. here,
Although two magnetic heads are used and recording or reproduction is performed simultaneously with these magnetic heads, the same effect can be achieved even if three or more magnetic heads are used.

In the same figure, the memory 10a of the recording circuit 1 is for setting the time axis compression and recording timing of the digital video signal for recording the digital video signal with the magnetic head 2a, and the memory 10b is for setting the recording timing for recording the digital video signal with the magnetic head 2a. It is for. When the recording mode ends, the memory loa.

As in the previous embodiment, the code blocks 10b hold the code blocks on the final track produced by the magnetic heads 2a and 2b, respectively.

Furthermore, a reproducing circuit 4a is provided for each magnetic head 2a, 2b.

4b, quality evaluation means 5a, 5b, display means 6a.

6b is provided, and the check result of the recording/reproducing function is displayed for each magnetic head 2a, 2b. Quality evaluation means 5
a and 5b have the same structure as the specific example shown in FIG. 2, but they can also have the structure shown in FIGS. 3 to 5. Here, a common set value S is used in the discrimination circuits 13a and 13b, and the quality evaluation means 5a and 5b are
When the configurations shown in FIGS. 5 to 5 are used, the set value S' is also common to these.

As a result, if a recording/reproducing function failure is displayed on either of the display means 6a, 6b, the magnetic head 6a,
When either one of the tapes 6b is clogged or dirty and both display means 6a and 6b display that the recording/playback function is defective, this generally means that the tape is defective, and the recording/playback function can be checked. becomes.

In this embodiment, one display means can be used by performing an OR operation on the outputs of the discrimination circuits 13a and 13b and supplying the result to the display means.

Conversely, in the embodiments shown in FIGS. 6 and 7, the reproduction circuit 9 quality evaluation means 9 display means is individually provided for the magnetic heads 2 and 2'', so that the magnetic heads 2 and 2' It is also possible to check the recording/playback function at each time.

In the embodiment described above, it is possible to check after a predetermined program or camera capture, but it is also possible to set a short-time recording mode and check the above-mentioned recording/playback function before performing such recording. You may do so. However, in such a method, it is necessary to rewind the magnetic tape to its original state in order to eliminate waste or waste of the magnetic tape or to perform continuous shooting, which takes time and effort.

First, as a solution to this problem, an embodiment of the present invention will be described which is provided with a mode in which a predetermined pattern of digital video signals is recorded/played in M2 according to a check command signal to check the recording/playback function. In this case, unlike the embodiments described above, a special pattern signal can be generated from a code pattern generator to perform a recording/playback check instead of a digital video signal for normal recording. However, the quality evaluation means and the quality evaluation method are the same as in the previous embodiments. Therefore, in the following description of the embodiments, description of these common parts will be omitted.

FIG. 9 is a block diagram showing the main parts of an embodiment of the digital recording and reproducing apparatus according to the present invention, which is equipped with a mode for recording and reproducing a predetermined digital signal pattern according to a command signal and checking the recording and reproducing function. 2 is a pattern generator, 22 is an input terminal, and parts corresponding to those in the previous drawings are given the same reference numerals.

In the figure, when a mode command signal M for starting the check mode is inputted from the input terminal 22 to the control means 7 by an operation by an operation means (not shown), the control means 7
controls the drive device 8 to advance the magnetic tape 3 as necessary, and causes the magnetic head 2 to scan the magnetic tape 3. At the same time, the pattern generator 21 generates a code block for one track having the same structure as, for example, a normal digital video signal to be recorded, and supplies it to the magnetic head 2 to record it on a track on the magnetic tape 3. . Next, the control means 7 controls the active device 8 so that the magnetic head 2 reproduces and scans the track on which recording has been completed. From here on, similarly to the embodiment shown in FIG. 1, this reproduced code block is code identified by the reproducing circuit 4, and
It is inspected and evaluated by the quality evaluation means 5 and the results are displayed on the display means.

In this way, it is possible to easily check the recording/reproducing function at any time with a simple operation without adding a read-only head or large-scale circuit.

Here, in the case of having a plurality of magnetic heads, the pattern generator 21 may generate a code block of a different pattern for each magnetic head, or the pattern generator 21 may generate a code block of the same pattern to be supplied to each magnetic head. May be used as a block.

Alternatively, a pattern generator may be provided for each magnetic head, and code blocks of different patterns may be supplied to each magnetic head independently. Furthermore, the quality evaluation means 5 and the display means 6 may be common to each magnetic head or may be separate (A).

Next, an example of control in the check mode of this embodiment will be explained in detail.

FIG. 10 is an explanatory diagram showing a specific example of the control method in the recording/reproducing function check mode of this embodiment.

In the figure, when a pulsed mode command signal M for starting the check mode is input, the magnetic tape 3 starts running along with this input, and then the pattern generator 21
Code blocks corresponding to one track from . . . are recorded on the magnetic tape 3. Thereafter, the magnetic tape 3 is rewound to reproduce the recorded track, and after that, reproduction for checking is performed and the magnetic tape 3 is stopped.

This ends the check operation of the recording/reproducing function, but the check results are retained by appropriate means and continue to be displayed on the display means 6.

FIG. 11 shows another specific example of the control system in the recording/reproducing function check mode. In this specific example, the mode command signal M rises together with the check mode command, and the check mode starts.

As in the specific example of FIG. 10, the pattern generator 21
After that, the magnetic tape is repeatedly rewound and reproduced for inspection until the mode command signal M falls. The check result is displayed until the mode command signal M falls, but the check result may be displayed for each test, or, for example, the check result based on the average of the results of previous tests may be displayed. It may be displayed.

In the specific example shown in FIG. 12, the operation is started by a mode command signal M, the code block from the pattern generator 21 is recorded, and then the magnetic tape 3 is rewound and replayed a predetermined number of times. It is designed to repeat. This repetition is set so that the check results are displayed for sufficient time to allow the user to make treatment decisions.

In the specific example shown in FIG. 13, the mode command signal M is divided into a start signal M1 and a stop signal ME.

As a result, as shown in the figure, the necessary rewinding of the magnetic tape 3 and playback for inspection are repeated, and the check results can be displayed during this period. Starting number M...
For example, an operation button may be provided for each stop signal M6,
Alternatively, one operation button may be provided, and each time the button is pressed, the start signal Ms and the stop signal ME may be generated alternately.

In the specific example shown in FIGS. 11 to 13 above, the rewinding of the magnetic tape 3 and the reproduction for inspection are repeated for the period necessary for display, but the quality evaluation means 5 or the display means 6
It is also possible to provide a means for retaining the evaluation results, and to perform tape rewinding and playback for inspection only once or multiple times, the tape playback system is stopped, and only the display continues for a desired period. The desired period may be until the next recording/reproducing function check is performed.

It may be a preset fixed period or a period until a reset signal is supplied.

In the specific example shown in FIG. 14, the code block from the activation pattern generator 21 is recorded in response to the mode command signal M, and after checking the reproduction, the magnetic tape 3 is rewound to the position before activation and then stopped. It is. By doing this, for example, even if the recording/reproducing function is checked during continuous shooting, normal recording/reproducing images can be prevented from being affected.

In the above specific example, the recording and reproducing function check was performed by feeding the magnetic tape 3 in such a manner that the tape pattern was the same as that for normal recording and reproducing. but,
As far as the recording/reproduction function check is concerned, there is no problem even if it is performed with the magnetic tape 3 stopped. 15th
In the specific example shown in the figure, the code block from the pattern generator 21 is recorded in accordance with the mode command signal M while the magnetic tape 3 is stopped without running up or rewinding the magnetic tape 3. Perform playback for, and
Even in this case, only reproduction for checking can be repeated as necessary, as in the specific example shown in FIGS. 11 to 14. At this time, since there is no need to rewind the magnetic tape by two runs, the drive device 8 can be easily controlled.

By the way, if recording and reproducing for checking is performed while the magnetic tape 3 is in a stopped state, there is a possibility that the recorded track for checking overlaps the track that was normally recorded immediately before. In the specific example shown in FIG. 16, after activation by the mode command signal M, the magnetic tape 3 is first run for a predetermined distance and then stopped, and then the recording/reproducing function is checked.
The magnetic tape 3 is rewound again to its original position and stopped.

This avoids the problem of overlapping tracks as described above.

The specific example described above can be realized within the scope of a system control device that is normally implemented by software, so a specific example of its implementation will be omitted.

Next, a specific example of the pattern generator 21 in FIG. 9 will be explained.

In the specific example shown in FIG. 17, a ROM is used as the pattern generator 21. The storage capacity of the ROM 21 may be at least the amount of code pattern data for one track, and data of a predetermined pattern is stored therein. When checking the recording/reproducing function, a pattern digital signal is read from the ROM 21 and compared with the digital signal reproduced from the magnetic tape 3.

In the specific example shown in FIG. 18, an M-sequence generator is used as the pattern generator 21. Even when checking the recording/reproducing function, the same pattern can be generated and compared for checking. Furthermore, since the M-sequence signal is a pseudo-random signal, it is possible to check the characteristics of the entire recording/reproducing system including the waveform equalization circuit.

In the specific example shown in FIG. 19, for example, a T pattern, 2
T pattern, 3T pattern (however, T is the minimum bit @)
A rectangular wave generator that generates a repeating pattern of rectangular waves with a predetermined cycle is used as the pattern generator 21. In this case, since the check signal is a rectangular wave pattern with a constant period, checking for code errors can be performed only by checking the periodicity of the reproduced signal. Therefore, code error detection can be performed without using a data synchronization circuit or the like.

FIG. 20 shows the pattern generator 21 in FIG. 9,
As shown in FIG. 19, it is a block diagram showing a specific example of the quality evaluation means 5 when a rectangular wave generator is used.

In the figure, the quality evaluation means 5 includes a pattern verification circuit 2.
3 is provided. The reproduced rectangular wave signal inputted from the reproduction circuit 4 is supplied to the pattern verification circuit 23. The pattern verification circuit 23 measures the polarity reversal interval of the reproduced rectangular wave signal and compares it with the polarity reversal interval of the pattern signal from the pattern generator 21, which is a rectangular wave generator. If the two polarity inversion intervals are different, a pulse is output from the pattern verification circuit 23 and counted by the counter 12.

Thereafter, the count value for one track is checked by the discrimination circuit 13 and displayed by the display means 6, as in the specific example shown in FIG.

FIG. 21 is a block diagram showing the main parts of still another embodiment of the digital recording/reproducing apparatus according to the present invention, and 21'
, 21''' is a pattern generator, and 24 is a switch.

In the figure, two pattern generators 21' and 21'' that generate different pattern signals and a switch 24 that selects these are provided.
To explain with reference to FIG. 2, after the first pattern (pattern A) from the pattern generator 21' is recorded, played back and checked, the selector switch 24 is reversed and the second pattern from the pattern generator 21'' is recorded. (Pattern B) is recorded on the same trunk, played back, and checked.In this way, the override characteristics of a recording/playback device that records a new signal by override without using an erase head can also be checked and evaluated. can do.

In this embodiment, it is also possible to increase the number of pattern generators and check them.

As shown in FIG. 23, the override characteristic can be checked even if the reproduction check is performed only on the last recorded pattern and only the recording is performed on the previous patterns.

In each of the embodiments described above, the quality of the reproduced signal is evaluated by detecting code errors.

By viewing the image signal on a monitor or the like, it is also possible to evaluate the quality based on the image quality. FIG. 24 is a block diagram showing still another embodiment of the digital recording and reproducing apparatus according to the present invention for realizing this, in which 25 is a digital image generator that generates a digitized image signal, 26
is a D/A converter, 27 is a monitor or E V F (E
1 electronic View F 1der).

In the figure, a digital image generator 25 outputs a digital signal that becomes an image signal after D/A conversion, and is recorded and reproduced by the magnetic head 2. The reproduced digital signal is code-identified by the reproduction circuit 4, and is converted into a digital signal by D/A conversion @ 26 without error correction.
Converts to analog video signal and displays on monitor or EVF2
7. This allows the user to judge the quality by visually checking the display screen. here,
If this image signal is a vertical striped test signal such as a color bar, the digital image generating circuit 25 only needs to repeatedly generate signals for one to several lines, and the circuit size can be small. This does not pose a particular problem even in the segment recording method, since only one track (one segment) can be repeatedly reproduced and these can be assembled and displayed in one field. In this case, by reproducing the same track with a plurality of heads, it can be determined which head's performance is deteriorating by seeing which part of the reproduced screen has deteriorated in the image.

In the embodiment in which the recording/reproducing function is checked using the mode command signal M described above, a plurality of heads are alternately operated with the same configuration as in the embodiment in which the check is performed at the end of the recording mode such as program or camera shooting. It goes without saying that it can also be applied to the case where recording and reproduction are performed simultaneously.

In that case, when an image signal is used as a check signal as in the embodiment shown in FIG. It is only necessary to repeat the steps, and the circuit size does not increase. Furthermore, with such an image pattern, one recording track can be used for checking a plurality of magnetic heads when azimuth recording is not performed or when the same azimuth head is used.

Although the above embodiments are all applied to a digital VTR, it goes without saying that the present invention can be applied to other systems such as optical disks, magnetic disks, audio recorders, etc.

[Effects of the Invention] As explained above, according to the present invention, without adding a read-only head or a processing circuit for the playback signal of the head,
It becomes possible to check the recording/reproducing function using the information signal recording/reproducing head, and the device can be made smaller, lighter in weight, and lower in power consumption.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a digital recording/reproducing apparatus according to the present invention, FIG. 2 is a block diagram showing a specific example of the recording circuit and quality evaluation circuit in FIG. 1, and FIGS.
5 is a block diagram showing another specific example of the quality evaluation means in FIG. 1, FIG. 6 is a block diagram showing another embodiment of the digital recording/reproducing apparatus according to the present invention, and FIG. 7 is a block diagram showing another example of the quality evaluation means in FIG. FIGS. 8 and 9 are block diagrams showing further embodiments of the digital recording and reproducing apparatus according to the present invention, and FIGS. 9 are operation explanatory diagrams of the embodiment shown in FIG. 9, FIGS. 17 to 19 are block diagrams showing specific examples of the pattern generator in FIG. 9, and FIG. 20 is a block diagram of the pattern generator in FIG. 2 is a block diagram showing a specific example of the quality evaluation means when the specific example of FIG. 19 is used.
FIG. 1 is a block diagram of main parts showing still another embodiment of the digital recording/reproducing apparatus according to the present invention, and FIGS. 22 and 23 are
The figures are an explanatory diagram of the operation of the embodiment shown in Fig. 21 and Fig. 24, respectively.
The figure is a block diagram showing still another embodiment of the digital recording/reproducing apparatus according to the present invention. 1...recording circuit, 2...magnetic head,
3...Magnetic tape, 4...Reproduction circuit, 5
・・・・・・Quality evaluation means. 6.6a, 6b - display means, 10.10', 10''
. 10a, 10b---Memory, 11.
11', lla, llb--comparison circuit, 12
．． 12', 12a, 12b---counter. 13, 13', 13a, 13b...Discrimination circuit, 14...Latch circuit, J5...
Comparison circuit, 16...Error long hand JQ circuit, 17.
...Judgment circuit, 18.20...Switch,
21.21'. 21″... Pattern generator, 22...
Mode command signal input terminal, 25...Digital image signal generator, 26...D/A converter. Agent Patent Attorney Takeshi Kenjibe (1 other person) Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 13' +60 Figure 6 Figure 7 Figure 8 Figure 9 Figure 1 o Figure □ - L Kaku No. Figure 11 - Do Gyugyu Ig JrM
-17=/'On the other hand, I-1riio barrier)'Z and Figure 12-7-Do index value number M
--1□Measure 13 Time * 14 Time 9 $15 Time rlil Figure 16 Time Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 21"

Claims (1)

[Claims] 1. In a digital recording and reproducing apparatus that records and reproduces a digital information signal consisting of a series of code blocks of a predetermined size on a recording medium, when the recording of the digital signal is completed, the digital information signal is placed at a predetermined position on the recording medium. Reproducing means for reproducing a specific code block of the recorded digital signal; quality evaluation means for evaluating the quality of the specific code block;
1. A digital recording/reproducing apparatus comprising: a display means for displaying the evaluation result by the quality evaluation means. 2. In claim 1, the recording circuit is provided with a memory for storing the specific code block when recording the specific code block in the predetermined position of the recording medium, and the quality evaluation means is configured to record the specific code block read from the memory. A digital recording and reproducing apparatus characterized in that the quality of the specific code block reproduced by the reproducing means is evaluated based on the code block of . 3. The digital recording/reproducing apparatus according to claim 2, comprising a plurality of recording/reproducing heads for the digital information signal, and the memory is provided for each recording/reproducing head. 4. In claim 3, the recording/reproducing head sequentially reproduces the digital information signal from the recording medium, and a switch for selecting each of the specific code blocks sequentially reproduced from the recording/reproducing head. A digital recording and reproducing apparatus, characterized in that it comprises means for supplying a particular code block from said switching means to said single quality evaluation means. 5. A digital recording and reproducing apparatus according to claim 3, wherein the quality evaluation means and the display means are provided for each of the recording and reproducing heads. 6. A digital recording/reproducing apparatus according to claim 1, wherein the recording medium is a magnetic recording medium. 7. In claim 6, the recording/reproducing head for the digital information signal is a rotary head, and the code block is recorded on one track of the digital information signal, and the track on which the specific code block is recorded is the recording head. A digital recording and reproducing apparatus characterized in that the last track of the digital information signal formed by a reproducing head. 8. In claims 1 to 7, the quality evaluation means includes a measuring means for measuring the number of code errors in the specific code block during a reproduction period or a part thereof, and 1. A digital recording/reproducing apparatus comprising a determining means for determining the magnitude relationship between the number of errors and a preset value. 9. In claims 1 to 7, the quality evaluation means includes a measuring means for measuring the maximum length of consecutive code errors in the specific code block during a reproduction period or a part thereof; 1. A digital recording/reproducing apparatus comprising: a determining means for determining the magnitude relationship between the maximum length of the consecutive code errors and a preset value. 10. In claims 1 to 7, the quality evaluation means measures the number of code errors of a predetermined length or more in the specific code block during a reproduction period of the specific code block or a part thereof. 1. A digital recording/reproducing apparatus comprising: means for detecting code errors; and determining means for determining a magnitude relationship between the measured number of code errors and a preset value. 11. In claims 1 to 7, the quality evaluation means includes a first measuring means for measuring the number of code errors of the particular code block during a reproduction period of the particular code block or a part thereof; a first determining means for determining the magnitude relationship between the measured number of code errors and a preset value; and a maximum length of consecutive code errors in the specific code block during the measurement period of the first measuring means. a second measuring means for measuring the length of the consecutive code errors; a second determining means for determining the magnitude relationship between the measured maximum length of the consecutive code errors and a preset value; and the first and second determining means. 1. A digital recording/reproducing apparatus comprising: determination means for determining a recording/reproducing function based on a determination result of the determination result. 12. In a digital recording/reproducing device for recording and reproducing a digital information signal consisting of a series of code blocks of a predetermined size on a recording medium, a pattern generating means for generating a predetermined pattern of digital code blocks, and a pattern generating means for recording based on a command signal. a control means for recording the digital code block on a recording medium and then reproducing the digital code block by controlling the digital code block; a quality evaluation means for evaluating the quality of the reproduced digital code block; and an evaluation by the quality evaluation means. 1. A digital recording/reproducing device comprising display means for displaying results. 13. The digital recording and reproducing apparatus according to claim 12, comprising a plurality of recording and reproducing heads for the digital information signal, and the pattern generating means is provided for each recording and reproducing head. 14. In claim 13, the recording/reproducing head sequentially reproduces the digital information signal from the recording medium, and the recording/reproducing head sequentially reproduces each digital code block into a single A digital recording and reproducing device, characterized in that the digital recording and reproducing device supplies information to the quality evaluation means. 15. The digital recording and reproducing apparatus according to claim 13, wherein the quality evaluation means and the display means are provided for each of the recording and reproducing heads. 16. In claim 12, a plurality of recording and reproducing heads for the digital information signal are provided, and the digital code block having the same or different pattern is supplied to each of the recording and reproducing heads from a single pattern generating means to perform the recording. A digital recording/reproducing device characterized by recording on a medium. 17. In claims 12 to 16, the control means controls the reproduction means to repeatedly reproduce the digital code block during the duration of the command signal, and the quality evaluation means controls the reproduction means for each reproduced digital code block. A digital recording and reproducing device characterized by evaluating quality. 18. In claims 12 to 16, the control means controls the reproduction means to repeatedly reproduce the digital code block a predetermined number of times, and the quality evaluation means evaluates the quality of each reproduced digital code block. A digital recording and reproducing device characterized by: 19. In claims 12 to 16, the control means controls the reproduction means to repeatedly reproduce the digital code block until a stop signal is input, and the quality evaluation means controls the reproduction means for each reproduced digital code block. A digital recording and reproducing device characterized by evaluating quality. 20. In claims 17 to 19, the control means controls the drive means to drive the recording medium, and records the digital code block while the recording medium is being driven, and after recording, drives the recording medium. A digital recording and reproducing apparatus characterized in that the digital code block is reproduced every time the digital code block is driven by repeating the process of repeating and returning to the original state. 21. The digital recording/reproducing apparatus according to claim 20, wherein the recording medium is returned to its original state after the final reproduction of the digital code block. 22. Claims 17 to 19 are characterized in that the control means records the digital code block on the recording medium and reproduces the digital code block from the recording medium while the recording medium is stopped. A digital recording and reproducing device. 23. In claim 22, the control means controls the drive means to drive the recording medium by a predetermined amount before recording the digital code block, and when the digital code block is reproduced for the last time, the recording medium is A digital recording/reproducing device characterized in that it returns to the state of. 24. A digital recording/reproducing device for recording and reproducing a digital information signal consisting of a series of code blocks of a predetermined size on a recording medium, comprising: a pattern generating means for generating mutually different patterns of digital code blocks; control means for controlling recording means and reproduction means to sequentially record and then reproduce the digital code blocks from the pattern generation means on the recording medium; and a quality evaluation for evaluating the quality of the reproduced digital code blocks. 1. A digital recording and reproducing apparatus comprising: a means for evaluating quality; and a display means for displaying an evaluation result by the quality evaluating means. 25. The digital recording and reproducing apparatus according to claim 24, wherein the quality evaluation means evaluates the quality of each of the digital code blocks to be reproduced and generates a comprehensive evaluation result. 26. The digital recording and reproducing apparatus according to claim 24, wherein the reproducing means reproduces only the last recorded digital code block, and the quality evaluating means evaluates the quality of the digital code block. 27. A digital recording and reproducing apparatus according to any one of claims 24 to 26, characterized in that each digital code block from said pattern generating means is sequentially recorded in an overlapping manner on the same location on said recording medium. 28. Claims 12 to 27, wherein the quality evaluation means or the display means is provided with means for retaining the evaluation results, and the evaluation results are displayed on the display even after the last reproduction of the digital code block from the recording medium. A digital recording/reproducing device characterized in that it is capable of displaying information on a display device. 29. The digital recording and reproducing apparatus according to claim 28, wherein the display period of the evaluation results is constant. 30. The digital recording/reproducing apparatus according to claim 28, wherein the display period of the evaluation results is set until a display stop signal is input. 31. The digital recording and reproducing apparatus according to claim 28, wherein the display period of the evaluation result is until the input of the next command signal. 32. A digital recording/reproducing apparatus according to claim 12, wherein said pattern generating means is a read-only memory storing said digital code block. 33. A digital recording/reproducing apparatus according to claim 12, wherein said pattern generating means is means for generating a predetermined pseudo-random signal. 34. A digital recording/reproducing apparatus according to any one of claims 12 to 31, characterized in that said pattern generating means is means for generating a repetitive signal of a predetermined period. 35. In claims 12 to 34, the quality evaluation means includes a measuring means for measuring the number of code errors of the digital specific block during a reproduction period of the digital code block or a part thereof; 1. A digital recording/reproducing apparatus comprising a determining means for determining the magnitude relationship between the number of errors and a preset value. 36. In claims 12 to 34, the quality evaluation means includes a measuring means for measuring the maximum length of consecutive code errors of the digital specific block during the reproduction period of the digital code block or a part thereof; 1. A digital recording/reproducing apparatus comprising: a determining means for determining the magnitude relationship between the maximum length of the consecutive code errors and a preset value. 37. In claims 12 to 34, the quality evaluation means comprises a measuring means for measuring the number of code errors of a predetermined length or more in the digital code block during a reproduction period of the digital code block or a part thereof. 1. A digital recording/reproducing apparatus comprising: a determining means for determining a magnitude relationship between the measured number of code errors and a preset value. 38. In claims 12 to 34, the quality evaluation means includes a first measuring means for measuring the number of code errors of the digital code block during a reproduction period of the digital code block or a part thereof; a first determining means for determining the magnitude relationship between the number of code errors and a preset value, and measuring the maximum length of consecutive code errors in the digital code block during the measurement period of the first measuring means. Second to do
a measuring means, a second determining means for determining the magnitude relationship between the measured maximum length of the consecutive code errors and a preset value, and based on the determination results of the first and second determining means. 1. A digital recording and reproducing device comprising: determination means for determining a recording and reproducing function. 39. A digital recording/reproducing apparatus according to any one of claims 12 to 38, wherein the recording medium is a magnetic recording medium. 40. In a digital recording and reproducing apparatus for recording and reproducing a digital video signal consisting of a series of code blocks of a predetermined size on a recording medium, a pattern generating means for generating a digital code block representing a predetermined image pattern, and a command signal a control means for controlling the recording means and the reproduction means to record the digital code block on the recording medium and then reproduce it; a converting means for converting the reproduced digital code block into an analog video signal; 1. A digital recording and reproducing apparatus comprising: a display means to which a video signal is supplied and which displays an image. 41. A digital recording and reproducing apparatus according to claim 40, wherein the recording medium is a magnetic tape, and a plurality of rotating magnetic heads serve as recording and reproducing heads for the digital video signal and the digital code block.