JPH0512663A - Dropout analyzer - Google Patents

Abstract

PURPOSE:To rapidly and surely analize a dropout causing substance. CONSTITUTION:Based on an RF output and an SWP output attained at the time of reproducing a video tape T, dropout information containing the position of the dropout causing substance is operated by a computer 11. Based on this arithmetic result, the dropout causing substance on the video tape T is encircled visibly by a dot-like mark.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dropout analyzer suitable for measuring dropout of a VTR magnetic tape and analyzing the dropout.

[0002]

2. Description of the Related Art As a procedure for analyzing the cause of dropout on a video tape, a recording signal is recorded on the video tape, and a reproduced image thereof is confirmed on a monitor while searching for a dropout occurrence point.

Then, the running of the video tape is stopped at the position where the dropout occurrence point is found, and the videotape position of the dropout occurrence point portion is specified in cm order.

Subsequently, the dropout occurrence point is specified on the order of mm with an optical microscope or the like, and the dropout cause substance is analyzed with the SEM (scanning electron microscope) or the like.

[0005]

However, it is extremely difficult to specify the dropout occurrence point on the actual video tape, and during the specification of the dropout occurrence point, another factor is analyzed. There is a high possibility that they will be subject to proper analysis.

[0006] In addition, whether dropouts are periodic or sporadic,
It was also difficult to analyze statistically.

An object of the present invention is to provide a dropout analyzer capable of quickly and accurately analyzing a dropout cause substance.

[0008]

The dropout analyzer according to the present invention is a detecting means for detecting a dropout in which a reproduction output level of a video signal recorded on a magnetic tape T is lower than a preset level th. 11, 1
The dropout information including 3, 15 and at least the dropout detection position on the magnetic tape T is the detection means 1.
Computation means 11 that is computed based on the output signals of 1, 13, 15 and the computed dropout information are provided visually on the magnetic tape T corresponding to the dropout detection position. , 11, and are included.

[0009]

In the dropout analyzer according to the present invention,
Corresponding to the dropout detection position on the magnetic tape, dropout information including at least the detection position is provided on the magnetic tape.

Therefore, by visually recognizing the dropout information, the position where the dropout occurs can be visually recognized.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the dropout analyzer according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a dropout analyzer (DOA) system using an 8 mm video deck 1.

In FIG. 1, the power source portion at the rear of the input portion of the deck 1 is exposed to the outside of the deck 1, and the automatic Z stage 3 is provided with a dot impact head (DIH) 5.

The tip of the DIH 5 has a loading mechanism section 9
Of the magnetic tape (8 mm video tape) T and the tip position of the DIH 5 are set to several hundred [μm] so as not to damage the tape T. It is set.

The dropout is measured by the drop in the signal level when the video signal recorded on the tape T is reproduced.

That is, the SWP output (see FIG. 2) and the RF output obtained when the tape T is reproduced on the deck 1 are respectively detected, and the RF output has a cutoff frequency of 500.
It becomes an RF envelope through a low-pass filter of about [kHz] (see FIG. 3), and its RF output signal is A / D.
After conversion, the state of the reproduced signal is observed.

Then, the point where the RF output level is lower than the preset level th is detected as a dropout.

In this case, the SWP output of FIG. 2 and the RF of FIG.
The output (track length, dropout length, depth, position) and the RF output amplitude histogram (see FIG. 4) are input to the computer 11 and stored therein.

Then, based on the RF output, dropout information (longitudinal position, width direction position of tape T with reference to the measured position of dropout, depth of dropout from set level th, dropout The data such as the length and size of the data is calculated by the computer 11.

When the position of the dropout is calculated, the rotary encoder 13 attached to the pinch roller measures the amount of advance of the tape T from the reference position of the rotary drum 15, and the measured data. (Tape running information) is input to the computer 11 and calculated.

Then, in the computer 11, the tape T is placed at the position of the guide roller 9A based on the dropout information.
When the dropout-causing object comes, the mark surrounding the dropout-causing object is controlled by the DIH 5 via the control board 17.

In this case, the computer 11 stores the information regarding the dropouts A and B, as understood from FIG.

The centers of the circles A and B indicating the dropouts indicate the dropout positions on the tape T, and the circles A and B
The size of indicates the dropout depth or length.

A circular mark (for example, 160 dots / inch dot) is provided on the tape T so that the circles A and B are surrounded.

In this case, the dot is surrounded by a range of 100 [μm] around the dropout, so that the cause of the dropout on the tape T can be found and analyzed very quickly and accurately.

When the mark is applied to the entire width of the tape T, the DIH 5 is slid in the width direction of the tape T. In this case, the automatic Z stage 3 is moved.

As described above, in this embodiment, the mark surrounding the dropout-causing substance is provided on the tape T based on the dropout information, so that the dropout can be found and analyzed quickly and accurately. I can do it.

Further, since the size of the dropout can be analyzed from a medium size to a minute size, the analysis capability is improved.

Therefore, it is particularly effective in the dropout analysis of a tape for a short wavelength such as a vapor deposition type metal tape of 8 mm VTR for high image quality.

Note that it is possible to condition the range to which the mark is added by setting the parameters of the dropout analyzer. Also, when the dropout is continuous, by adding the mark, the cause of the dropout can be reduced. It is also possible to sample so that no mark is attached on the object.

In addition, as a method of applying the mark, for example, it is not necessary to surround the tape T in a circular shape, for example, by applying the mark to the lower portion (longitudinal direction) of the tape T.

Next, FIG. 7 shows a dropout analyzer using an open reel video deck 10. In principle, a dropout analyzer is marked around the dropout cause object in the same manner as in FIG. Is given.

In this case, a pedestal 20 of DIH 5 (formed of hard rubber) is provided, and a capstan 13A with a rotary encoder is provided.

Therefore, this embodiment also has the same effect as the above embodiment.

In addition, since the mounting space for the DIH 5 is sufficient, even if the width of the tape T is wide, the automatic Z stage 3 can be moved to apply marks over the entire width of the tape T.

[0036]

As can be understood from the above description, in the dropout analyzer according to the present invention, the dropout information corresponding to at least the dropout detection position on the magnetic tape is the magnetic tape. Granted on top.

Therefore, by visually recognizing the dropout information, the position where the dropout occurs can be visually checked.

As a result, it is possible to quickly and accurately search for the dropout-causing substance on the magnetic tape and analyze it.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a preferred embodiment of a dropout analyzer according to the present invention.

FIG. 2 is a waveform diagram of SWP output.

FIG. 3 is a waveform diagram of RF output.

FIG. 4 is a correlation diagram of an RF output amplitude histogram.

FIG. 5 is an explanatory diagram of dropout information stored in a computer.

FIG. 6 is an explanatory diagram of marks provided on the tape.

FIG. 7 is a configuration diagram of another embodiment.

[Explanation of symbols]

 1 8mm video deck 3 Automatic Z stage 5 Dot impact head 9 Loading mechanism 9A Guide roller 11 Computer T video tape

Claims (1)

Claim: What is claimed is: 1. A detection means for detecting dropout in which a video signal reproduction output level recorded on a magnetic tape is lower than a preset level, and a drop means at least on the magnetic tape. Computation means for computing dropout information including the out detection position based on the output signal of the detection means, and marking means for visibly providing the computed dropout information on the magnetic tape corresponding to the dropout detection position And a dropout analyzer.