JPH01267820A - Sheet for adjusting head azimuth of video floppy device - Google Patents

Abstract

PURPOSE:To improve the efficiency of head azimuth adjustment by recording reference signals for adjusting a head azimuth on plural adjoining tracks. CONSTITUTION:A center core 13 to position by engaging with a spindle 12 is equipped with an energizing spring 14 and further, a PG yoke 15 for detecting a phase is fixed. The reference signal for adjusting the azimuth is recorded at a period at an angle theta2 from an angle theta1 from the PG yoke 15 on a 1st track 16, a 25th track 17 and 49th track 18. The reference signal, for example, a few sets of signals whose azimuths are shifted on purpose are burst-recorded and the azimuth is adjusted from the relation among their reproducing output values. Thus, the reproducing output values of head gaps 4 and 5 of a head 1 having the plural head gaps 4 and 5 can be simultaneously checked and the head azimuth can be efficiently adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to head azimuth adjustment of a video floppy device which performs recording and reproduction by forming an annular track in a head section having a plurality of head gaps in a magnetic sheet. This relates to the door adjustment seat used for adjustment.

BACKGROUND OF THE INVENTION This type of video floppy device records one field of signals on one track, and when recording one frame image, two adjacent tracks are used. For this reason, it is common practice to provide two heads in the head gear 11 and scan these two tracks simultaneously. In addition, since the recording wavelength is less than 1 μm, head touch requires particularly high precision, but azimuth loss, which is caused by the azimuth error of head gap 1 during recording and playback, is directly responsible for the decrease in the playback output value. This can cause a significant loss of performance. Therefore, even in the process, the reference signal is recorded and the azimuth adjustment 1 is precisely performed using a friend head azimuth adjustment sheet.

FIG. 5 shows a graph of calculated values of azimuth loss. This graph has an azimuth error. Here, W=60 μm (track width), λ=0.
5 μm to α7 μm (recording wavelength), α=0 to 12′ (azimuth/shift). The trick that is more obvious than the graph is that α=
4', even though AL = 0.3 dB, α=l
When it becomes O', AL= 1.8 dB,
You can see how important azimuth adjustment is.

A conventional head azimuth adjustment method will be explained based on FIG. In FIG. 4, 1 is the head of the Video Flora 1 device, and the head 1 has a head azimuth adjustment sheet 2.
Corresponding to the tracks 3A and 3B, fC, two helad gear lugs 4.5 are provided.

These are indicated by the relative azimuth tdθ of head gear 14.5. The head azimuth adjustment of the head 1 is performed by reproducing the reference number (g) recorded on a specific track 3A with one head gap 4, and adjusting one head so that the reproduction output value of this head gap 14 is maximized. It is being carried out in an elaborate manner.

Problems that Moxibustion attempts to solve However, with the conventional head azimuth adjustment method, as shown in Fig. 4, even if there is no error in one head gap 4, there is a deviation in relative azimuth dθ in the other head gap 5. When a magnetic sheet with azimuth and misalignment α is reproduced in this state as a random error, the worst case (dθ+α) azimuth error will occur in the other heald gear graph 5. For example, the standard for azimuth and misalignment α is ±6′. year,
If head 1 with relative azimuth dθ of 4' is used, the worst case is 1.
When an azimuth shift of 0' occurs and the recording wavelength λ is cut to 1 μm' as shown in Figure 5, the azimuth loss AL increases and the reproduction output value decreases. There is a problem in that the quality of the video becomes poor due to the influence of the reduction.

In addition, when manufacturing a thin film head, a plurality of head gaps are formed on the same substrate, and each head gap is basically arranged in a straight line. As expected, there is a problem with adjustment using a single headgear solenoid.

Therefore, it is conceivable to adjust multiple head gaps 4.5, but if two conventional head azimuth adjustment sheets are used, it is possible to adjust the head azimuth adjustment sheet for a specific trunk 3AKt, or for a friend for which no reference signal is recorded, for head 1. (I- Adjustments were made while moving, which was extremely inefficient.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a sheet rack for head azimuth adjustment of a video floppy device that can improve the efficiency of head azimuth adjustment.

Companion Means to Solve All Problems In order to solve the above problems, the present invention records reference signals for head azimuth adjustment in a plurality of adjacent tracks.

Furthermore, the present invention provides a reference signal for head azimuth adjustment recorded in a track corresponding to each head gap of a plurality of adjacent tracks. , recorded with their relative positions shifted.

Effect: With the above configuration, reference signals for head azimuth adjustment are recorded in a plurality of adjacent tracks, so that the reproduction output value from each head gap of a head having a plurality of head gaps 1 used for frame reproduction etc. It becomes possible to check at the same time, and head azimuth adjustment can be performed efficiently.

Furthermore, the reference signals on adjacent tracks are recorded with their relative positions shifted, and even if the reference signal is recorded with a wider track width than the original one in order to eliminate errors due to tracking errors. Interference of reference signals between tracks is prevented.

EXAMPLE Hereinafter, an example of the present invention will be described based on the drawings. Note that the same components as those in FIG. 4 of the conventional example are given the same reference numerals and explanations will be omitted.

FIG. 1 is a plan view of a head azimuth adjustment sheet (hereinafter referred to as adjustment sheet) of a video floppy device showing an embodiment of the present invention. The shape of the adjustment sheet 11 is exactly the same as that of a video floppy. That is, the center core 13 that engages with and positions the spindle 12 is provided with a biasing spring 14, and is further equipped with a PG yoke 15 for phase detection.
is fixed.

A reference signal for azimuth adjustment is recorded on the first track 16, the 25th track 17, and the 49th track 18, respectively, for a period of angle θ2 from the angle θ1 from the PG yoke 15. For this reference signal, for example, the azimuth may be intentionally shifted, several sets of ratio signals may be recorded, and the azimuth may be adjusted based on the relationship between their reproduction output values. In addition, the 2nd Towotsuku 19, the 2nd
The same signals as the 1st track 16, the 25th track 17, and the 49th track 18 are applied to the 6th track 20, the 50th track 21, and the 49th track 18, respectively, with the phase shifted by π, and at the opposite positions symmetrical to the center. Record. For this reason, the first track 16 and the second track 19 are located on the outer circumferential side, the 25th track 17 and the 26th track 20 are located on the middle part, and the 49th track
Track 18 and 50th track 21 allow you to check the azimuth adjustment on the inner circumference side. In this process, the phase, that is, the relative position of the reference signal, is shifted. Since the track width and track pitch are narrow, the original track width is modified on the adjustment sheet 11 to eliminate errors due to tracking errors. When recording signals, interference of reference signals between tracks can be prevented.

FIG. 2 shows the output waveform when reproduced on this adjustment sheet ll'. On this adjustment sheet 11, a burst record is recorded with azimuth deviations of ±30' and ±40° with respect to the reference within the angle θ2. This ±301, ±40°
The azimuth has been adjusted to the reference value when the reproduced output values of the signals become equal, and the larger the difference between the left and right reproduced output values, the more the azimuth is shifted.

In Fig. 2, A is the waveform when the outer track (for example, the first track 16) is reproduced with a head gap of 4, and B is the waveform when the inner track (fc and Eva 2nd track 19) is reproduced with the head gap of 5. It is a waveform.

Since these output waveforms can be observed at the same time using the Mesiscope 1, very efficient adjustment can be performed when this adjustment sheet 11 is used.

FIG. 3 shows the relative azimuth dθ? with a head gap of 4.5 using the adjustment sheet 11 of FIG. 1. The head 1 which has been adjusted is in good condition, and if adjusted in this way, 2
Both head gaps ``4.5'' are d0 relative to the standard.
This results in an azimuth error of /2. This method adjusts the azimuth error tdV2, and when reproducing a magnetic sheet with an azimuth deviation α as a random error, the worst case is an azimuth error, whereas in the past it would be an azimuth error (dθ + α). (d''/2+α), and for example, if the standard for azimuth/displacement α is ±6' and a head 1 with relative azimuth dθ of 4' is used, the worst deviation will be 81, which is the worst case under the same conventional conditions. The azimuth error of 10' is improved by 10'. In the device shown in Fig. 5, when the recording wavelength input is cut to 1 μrn', this difference of 21 is large, and the azimuth loss AL? is greatly improved, and the reproduction output value is It is possible to prevent cost reduction and improve the quality of the video.

According to the present invention, a reference signal for head azimuth adjustment is applied to a plurality of adjacent tracks. Since it is recorded, it is possible to simultaneously check the reproduction output value of each head gap of a head having multiple heald gear gaps.
Head azimuth adjustment can be done efficiently.

Furthermore, since the reference signals of adjacent tracks are recorded with their relative positions shifted, even if a reference signal with a wider track width than the original one is recorded in order to eliminate errors due to tracking errors, Interference between tracks can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a head azimuth adjustment sheet of a video floppy device showing an embodiment of the present invention, and FIG. 2 is an output waveform diagram when the same head azimuth adjustment sheet is reproduced.
Figure 3 is an explanatory diagram of the head adjusted using the head azimuth adjustment sheet Th, Figure 4 is an explanatory diagram of the head adjusted by the conventional method, and Figure 5 is the azimuth deviation and azimuth loss based on the calculation results. FIG. 1...Head, 4.5...Head gap, 11.
...Bed azimuth adjustment sheet, 16-21...Track, dθ...Relative azimuth, α...Azimuth/displacement of magnetic sheet. Agent Yoshihiro Morimoto.・′] l Figure n. If -P(:T3-7 Figure 2 and 6 Figure 3 and Figure 4 1+7

Claims (1)

[Scope of Claims] 1. A head azimuth adjustment sheet for a video floppy device in which reference signals for head azimuth adjustment are recorded in a plurality of adjacent tracks. 2. A head azimuth adjustment sheet for a video floppy device, in which reference signals for head azimuth adjustment are recorded in tracks corresponding to respective head gaps of a plurality of adjacent tracks, with their relative positions shifted.