JPH036561B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a device for producing a standard tape (hereinafter referred to as standard (denoted as VTR).

Conventional configurations and their problems In recent years, VTRs have become smaller and lighter, and recording tracks have become more dense.Currently, Hi-Fi audio is considered a selling point, and the PCM method using a rotating head has been introduced. It will be needed in the future.
For this reason, the amount of magnetic tape wrapped around a cylinder with a rotating head is larger than before, but in order to ensure good running, it is preferable to have a small amount of magnetic tape wrapped, so overlapping is required to ensure signal continuity. The direction is to decrease the allowable amount of area,
For example, in the case of 8mm video standards, the head switching position must be adjusted with high precision to about 1/5 of the conventional tolerance. Currently, the head switching position can be adjusted by playing back a standard tape recorded on a standard VTR that has better performance than the production VTR, and then adjusting the production VTR's head switching position based on the vertical synchronization signal of the playback signal. This is the most common method, and in order to maximize the precision of the head switching position, it is necessary to increase the precision of the vertical synchronizing signal recording position on the standard tape.

In addition, recently, the penetration rate of VTRs has increased rapidly and production has increased rapidly, and this trend is expected to further develop in the future.In order to respond to this trend, we must increase the production volume of standard tapes. Therefore, it is necessary to improve productivity.

A conventional method for confirming the recording position of a vertical synchronizing signal when creating a standard tape will be described below.

Figure 1 shows a video track of a conventional standard tape. 1 is a magnetic tape, and 2 is a video track recorded faithfully to the standard, which is recorded alternately by two heads with azimuths in opposite directions. be. 3 is a vertical synchronizing signal recorded on a part of video track 2, and if track 2 is video width recording, it is located 6 to 7H after 6. Figure 2 is a time chart showing the relationship between synchronization signals and switching signals. 4 is a synchronization signal (a part of the horizontal synchronization signal and vertical synchronization signal) of the video signal recorded on the video track 2, and 5 is a cylinder unit. P _G
(not shown) is a head switching signal that determines the recording start position 6 and recording end position 7 of the video track 2. When the signal is in a HIGH state, the signal is applied to the head (not shown). A video track 2 is recorded on a magnetic tape 1.

When checking the vertical sync signal recording position on conventional standard tapes and standard VTRs configured as above,
The most preferable method for accuracy is to develop the recorded magnetic tape using fine iron powder, etc., and then measure the dimensions shown in Figure 1a using a microscope. It is extremely difficult to develop the signal to the extent that it can be clearly identified. Furthermore, even if the problem could be improved by improving the developer and making full use of advanced techniques for development, it would be extremely difficult to distinguish the vertical synchronization signal from a complex mixture of recorded signals, and this would be impractical.

The most practical method is to measure the dimensions of the video track recording start position (Fig. 1b) with a microscope, and then
The time d from the rising position of the head switching signal 5 to the leading edge c of the vertical synchronizing signal shown in FIG. There is a method of calculating the recording position of the vertical synchronization signal by adding the vertical synchronization signal to 2 (indicated by a solid line), the dimension b becomes as shown in FIG. 3, and the vertical synchronization signal determined by the time d shown in FIG. 2'
(Dotted line) It is assumed to be at position 8 above, and the dimension from b is e, and it is determined that it is at position 9 for actual track 2. However, the actual vertical synchronization signal is at position 10. The virtual position 9 is f
This results in an error of g in the longitudinal direction of the track, resulting in a measurement error in the vertical synchronizing signal recording position, and therefore it is impossible to improve the accuracy of the vertical synchronizing signal recording position on the standard tape. Furthermore, since running is unstable on the cylinder entry/exit side, bending as shown in FIG. 3 always occurs.

As mentioned above, conventional standard tapes have a problem in that high precision cannot be achieved because the vertical synchronization signal recording position cannot be accurately measured when creating the standard tape.

In addition, as a means to solve the above problem, the method shown in FIG. 4 can be considered. In FIG. 4, 11 is a CH ₁ video track, 12 is a CH ₂ video track, and 13 is a vertical synchronization signal recorded on each track Unrecorded gate created based on the standard (not shown)
This is an unrecorded area formed in . Further, the above-mentioned unrecorded portion is configured to be generated only when a tape for confirming the recording position of the vertical synchronization signal is created using the switching switch.

When confirming the vertical synchronizing signal recording position with the above configuration, it is sufficient to provide an unrecorded area using the switching switch and measure the dimensions of the unrecorded start position (n in FIG. 4) of the recorded and developed pattern. Furthermore, when creating a standard tape for production use, it is sufficient to release the unrecorded portion using the SW, but adding this means will cause the following problem. First, before starting recording on a standard tape, we check whether the tape pattern and all signal contents satisfy the standard tape specifications.The tape pattern is checked for video track linearity, recording start and end positions, and audio. Since the position and height of the control head, etc. are determined by developing the recorded signal and measuring its mechanical dimensions using a microscope, adding the above-mentioned new means requires the use of a recording tape for confirmation. A new type of tape must be created, which increases the time required for recording, as well as the time required to replace the sample with a microscope and reset the measurement standards during measurement, which increases confirmation time and reduces the efficiency of standard tape creation. However, a problem arises.

Further, an increase in the number of recording modes causes problems such as complicated handling, poor workability, and the possibility of operational errors.

Purpose of the Invention The present invention improves the accuracy of the vertical synchronization signal recording position by providing means for directly reading the vertical synchronization signal recording position of the video signal from the developed pattern in the recording mode of a standard tape for audio fixed head position adjustment. At the same time, the purpose is to provide a standard VTR with improved standard tape production efficiency.

Structure of the Invention The present invention makes it possible to read the vertical synchronization signal recording position with high precision from a developed tape pattern by forming a video track with a signal format different from other parts based on the vertical synchronization signal of the video signal to be recorded. The recording position can be highly accurate, and the measurement efficiency can be improved by making the above reading possible in a mode that creates a standard tape to adjust the distance from the fixed audio head cylinder. It is possible to measure the efficiency of standard tape production.

DESCRIPTION OF THE EMBODIMENTS Figure 5 shows a standard VTR tape running system, with 14
is a cylinder, 15 is a guide post, and 16 is a fixed head for recording audio and control signals. Figure 6 shows a standard VTR recording gate that creates the standard tape necessary to adjust the distance from the cylinder of the fixed audio head installed on the VTR.
17 is a time chart showing the gate of the vertical synchronization signal measurement standard. Reference numeral 17 indicates the current flowing to CH ₁ of the rotating video head (not shown) based on the _PG (not shown) provided in the cylinder 14. ON,
18 is a gate signal that turns OFF, and has an overlap of j before and after the video width i.
This is a gate signal that turns on and off the current flowing to CH ₂ , and has a phase difference of 180° from that of 17 above. 19
is a gate that turns on and off with the video width i, 20 is a pulse signal from which a vertical synchronization signal is extracted at a rate of one in every five tracks of CH ₁ , and 21
is the CH ₁ gate signal 17 and the pulse signal 20
Gate signals 17 and 21 are selected by a switching switch (not shown) provided in the device and turn on the current of the CH ₁ video head.
Turn off. 22 is a gate signal that turns ON/OFF the current flowing to the audio head of the fixed head 16;
The gate 22 turns OFF based on the rising edge of the pulse 20 and turns ON at the falling edge of the pulse 19.
is also configured to be selected by the CH ₁ head switching SW, and when the CH ₁ gate signal is 21, it becomes 22 and 1.
7, it is ON for the entire period. FIG. 7 shows the magnetic tape pattern recorded by the gates 18, 21, and 22 shown in _FIG . CH ₁ track, CH 2 track recorded up to the vertical synchronization signal at a rate of one in five tracks.
5 is the CH ₂ track, 26 is the audio track, and 27 copies are unrecorded. 28 is a control signal.

Also, Figure 8 shows the recording pattern shown in Figure 7.
Shows the video and audio signals obtained when played back on a VTR, and 29 shows the video width section played.
CH ₁ signal, 30 is a CH ₁ signal that has been reproduced up to the vertical synchronization signal at a rate of one in five, 31 is a CH ₂ signal,
32 is an audio signal and 33 is a no-signal section.

The procedure for creating a standard tape using the standard deck of this embodiment constructed as described above will be explained.

First, before creating a standard tape, the performance of each part of the tape pattern must be checked, and the switching
Set the CH ₁ gate to 21 and the audio gate to 22 in Figure 5 using the SW, and after recording the time during which a sample of the development pattern can be created, develop the recorded area using fine iron powder, etc. to create a sample. do. After that, use a microscope to measure the video track linearity, recording start position, recording end position, audio control track height, etc., and measure the k method (track center) shown in Figure 7 to calculate the error with respect to the standard value. If not satisfied, correct the vertical sync signal recording position and check again. Also, measure the dimensions from the unrecorded start part of the audio track to the unrecorded start part of the CH ₁ track, and tape the fixed head 16 so that it has the dimensions shown in FIG. 5 when the fixed head 16 is in a predetermined position. Adjust by moving it in the longitudinal direction of 1.

In the case of the video track linearity measurement described above,
When measuring the CH ₁ track, it is difficult to measure because there is an unrecorded part in 1 out of 5 tracks, so there is no problem if you measure the CH ₂ track. As mentioned above, all the performance checks regarding tape patterns can be performed using one type of recording tape. When creating a standard tape for audio fixed head position adjustment, record in the above recording mode, and when creating a normal standard tape, use the switching switch to set the CH ₁ gate to 17 in Figure 6 and set the audio gate to 17. Recording is performed by switching so that no recording part occurs.

Next, a method of adjusting the head switching position and the fixed audio head position when adjusting a VTR using the standard tape recorded as described above will be explained.

First, when adjusting the head switching position, play the standard tape recorded in the normal state described above, observe the vertical synchronization signal of the video playback signal and the head switching signal in the oscilloscope's 2 development mode, and make sure that both are at the predetermined position. Highly accurate settings can be made by adjusting the head switching position of the VTR to match the relationship.

When adjusting the position of the fixed audio head, play the standard tape created in the standard tape recording mode for adjusting the fixed audio head position, and observe the video playback output using the oscilloscope's 2-development mode as shown in Figure 8. , up to the vertical sync signal is played back.
Adjust the position of the audio fixed head so that the deleted part of the CH ₁ video signal 30 and the deleted part 33 of the audio signal 32 match. By doing this, the position of the audio fixed head of the VTR to be adjusted is determined. The position can be set with high precision, and it is possible to prevent a time lag between the video signal and the audio signal during compatible playback between multiple VTRs.

In the above embodiment, the tracks after the vertical synchronization signal of the CH ₁ track were configured as unrecorded, but the position in the developed pattern can be sufficiently identified, and when observing both signals with an oscilloscope as shown in FIG. Similarly, if the signal can be identified, there is no problem in recording the signal. In particular, in VTRs in which a pilot signal is superimposed on the video track and recorded, and the tracking servo system is operated by the reproduced signal from the pilot during playback, there is a problem that the servo is disturbed in the unrecorded area. It is necessary to write these marks continuously on all tracks to form tracks that can be identified by signals other than the pilot signal.

Effects of the Invention The present invention is a VTR equipped with a rotating video head and a fixed head for audio, in which a track portion with a signal form different from other portions is formed based on a vertical synchronization signal of a video signal to be recorded, and a developed pattern is formed. By configuring the vertical synchronizing signal recording position to be directly measured, the vertical synchronizing signal recording position on the standard tape can be highly accurate, and the head switching position of the VTR to be adjusted can be adjusted with high precision.

In addition, by providing the plurality of tracks and keeping the audio fixed head in a non-recording state during the formation of the track section, it is possible to check all the performance related to the tape pattern in one type of recording mode. This method is effective in increasing the efficiency of standard tape creation because the time required for performance confirmation before and after standard tape creation can be shortened.

[Brief explanation of the drawing]

Fig. 1 is a video track pattern diagram showing a conventional method for confirming the vertical synchronizing signal recording position of a standard tape, Fig. 2 is an electrical signal waveform diagram showing a conventional method of confirming the vertical synchronizing signal recording position of a standard tape, and Fig. 3 The figure is a video track pattern diagram showing the causes of errors in the conventional vertical synchronization signal recording position confirmation method. Figure 4 is a video track pattern diagram showing another conventional vertical synchronization signal recording position confirmation method. Figure 5 is the standard.
Plan view showing part of the VTR tape running system, No. 6
The figure is a signal waveform diagram showing the recording gate of a standard VTR in the rotating head type magnetic recording and reproducing apparatus of the present invention.
Figure 7 is a tape pattern diagram recorded in the mode for creating a standard tape for audio fixed head position adjustment of the standard VTR of the same device, and Figure 8 is the playback when the same standard audio head position adjustment tape is played back. It is a signal diagram. 14...Cylinder, 15...Guidance post, 1
6... Fixed head, 23, 24... CH ₁ track, 25... CH ₂ track, 26... Audio track, 27... Unrecorded section, 28... Control signal.

Claims (1)

[Claims] 1. A rotating video head forms a video track diagonally with respect to the magnetic tape, and a fixed head forms an audio track in the longitudinal direction of the magnetic tape, based on the vertical synchronization signal of the video signal to be recorded. A gate signal is provided, and the gate signal is used to form a track section having a different signal form from other tracks for each of the plurality of tracks of the video track, and the audio track is placed in a final recording state during the period when this track section is formed. A rotating head type magnetic recording and reproducing device.