JPH01138646A - Tracking control system for r-dat - Google Patents

Abstract

PURPOSE:To accurately control a tracking and to attain a reproducing even when one side of head is defective at the time of recording by recording a preliminary ATF pilot beforehand at the position of a regular ATF (Automatic Track Finding) pilot signal. CONSTITUTION:First, preliminary ATF pilot signals 301-305 are recorded only for the width of the track of the upper half of a position corresponding to regular ATF pilot signals 312, 322, 332, 342 and 352 to a tape 2 beforehand. At the time of recording, overwriting is executed to the signals 301-305 by a plus azimuth head (+H) or a minus azimuth head (the inverse of H) and a signal is recorded. When the +H is defective at the time of recording, for music azimuth tracks 31a, 33a and 35a, the signal is recorded with a track width and signals 302 and 304 remain between respective ones. Consequently, when the signal 331a of the track 33a is detected, next, detecting is executed in the sequence of the signals 302 and 304. Thus, even when one side head becomes defective, the reproducing can be correctly executed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a tracking control method for R-DAT, and particularly relates to a tracking control method for R-DAT, and in particular, it is capable of performing tracking control even if one of the positive azimuth head or the negative azimuth head becomes defective during recording. The present invention relates to an R-DAT tracking control method that can be performed accurately.

R-DAT is a rotary head.
) type DAT (Digital Audio Tape)
It has superior performance in terms of SZN ratio 5 frequency characteristics, distortion rate, dubbing characteristics, random access, etc., compared to conventional analog tape radars.

[Conventional technology]

In recent years, research and development of DAT has progressed, and in particular, R-DAT, which can be applied to VTR technology, has already been put into practical use. This R-DAT is, for example, approximately 6°23° with respect to the tape.
Data signals such as stereo music are digitized and time-compressed and recorded on a trunk having a width of 13.6 μm and having an angle of . When reproducing recorded signals, it is necessary for the head to accurately trace the trunk, and for this reason, as part of the R-DAT standard, the part where data signals such as stereo music are recorded (PCM A to perform tracking control on both sides of the part)
T F (Automatic Track Find
ing) signals. This AT
The F signal is composed of a sync signal and a pilot signal, and tracking control is performed by detecting the ATF signal recorded on each track during playback and changing the running speed of the tape.

FIG. 4 is a diagram for explaining the tracking control system of the conventional R-DAT. FIG. 4(a) shows the structure of the head provided on the rotating drum, and FIG. The relative relationship between the tape format and the moving head is shown to explain tracking control using the ATF signal.

As shown in FIG. 2(a), the head configuration of the conventional R-DAT is such that a positive azimuth head 111 and a negative azimuth head 112 are provided on the outer periphery of a rotating drum 101 at an angle of 1809. 103 has a wrapping angle of 90° around the rotating drum. Also these two azimuth heads 111.112
A rotating drum 101 provided with a tape 103 is configured to diagonally trace a tape 103 while rotating on a fixed drum 102. Then, the throat 111 to the positive azimuth
The negative azimuth head 112 has an azimuth angle of +20° with respect to the direction perpendicular to the head tracing direction, and the negative azimuth head 112 has an azimuth angle of −20° with respect to the direction perpendicular to the head tracing direction. °. As a result, when each azimuth head 111, 112 reproduces a signal recorded on each azimuth track, it is difficult to be influenced by the signal recorded on an adjacent track.

Here, R-DAT is generally not equipped with an erasing head, and signals are recorded (override) on the tape on which signals have been previously recorded by overlapping them with the plus azimuth head 111 and the minus azimuth nozzle 112. By doing so, a regular signal is recorded.

Further, the plus azimuth head 111 and the minus azimuth head 112 each have a width of 1.5 tracks (
20.4 .mu.m), and during recording, the signal is recorded by overriding the previous adjacent track by a width of 0.5 track (about 6.8 .mu.m).

By the way, in the R-DAT, various signals to be recorded and played back on the tape 103 are defined by a predetermined format, and tracking control is performed by the ATF on both sides of the PCM part.
and ATFt. That is, as shown in FIG. 4(b), for example,
When the positive azimuth head 111 traces the positive azimuth track 134, the positive azimuth head 111 traces the positive azimuth track 1 in ATFt.
34, the positive azimuth head 111 detects the ATF pyloft signal 1332 of the next adjacent negative azimuth track 133 after the track 134, and further detects the ATF pyloft signal 1332 of the negative azimuth track 133 adjacent to the front of the trunk 134. Detect ATF pilot signal l352. That is, the positive azimuth head 111 moving on the positive azimuth track 134 compares the strength of the leakage magnetic field from the ATF pilot signals 1332 and 1352 in the negative azimuth tracks 133 and 135 adjacent on both sides, and The running speed of the tape is changed so as to match the intensities of the detection signals from 1352. As a result, the positive azimuth head 111
Tracking is controlled to accurately trace on the plus azimuth track 134. Such ATF signals are recorded at two locations, ATF on both sides of the PCM portion and ATF2, for each track. Here, specifically, the ATF pilot signal is:
A signal of 130.67 KHz is used, a frequency that is hardly affected by azimuth loss.

[Problem that the invention seeks to solve]

As described above, the conventional R-DAT is configured to perform recording and reproduction on the tape 103 using two heads, a positive azimuth head 111 and a negative azimuth head 112. Tracking control is performed using A
This is done by detecting the sync signal and pilot signal of TF and ATF2.

By the way, the tape output of R-DAT is small (and the recorded signal may not be completely readable due to the thinness of the tape, contact with the head, adhesion of dust, clogging of the head, etc.) .

To this end, the R-DAT has various functions for correcting and supplementing errors during playback. For example, during playback, if the signal of one of the positive azimuth tracks or the negative azimuth track cannot be read, the recorded signal can be restored by interpolating the signal of the other readable azimuth track (average value interpolation). It can be played back. However, conventional R-DA
T is AT if no signal is recorded on either the positive azimuth track or the negative azimuth track.
Trunking control using the F signal could not be performed, and recorded signals could not be reproduced. In other words, in the conventional R-DAT, if one azimuth head becomes defective during reproduction and only the other azimuth head can read the signal, the other azimuth head read by the other readable azimuth head It was possible to reproduce the recorded signal by interpolating the average value of the track signal. However, if one azimuth head becomes defective during recording and no signal is recorded on the other azimuth track, even if both azimuth heads can read the recorded signal during playback, the R-DAT
It was not possible to perform tracking control using the ATF signal, and it was impossible to reproduce the recorded signal.

That is, as shown in FIG. 4(b), for example, if the minus azimuth head 112 becomes defective during recording and no signal is recorded on the minus azimuth track 13L 133,135, the plus 7 azimuth head 111
is the ATF sync signal 1 of the positive azimuth track 134
342 is detected, the ATF pilot signal 1332 of the next adjacent negative azimuth track 133 to that track 134 and the ATF pilot signal 1352 of the negative azimuth track 135 adjacent to the front of the trunk 134 are not recorded. , conventional R
- DAT was unable to perform tracking control. Further, for example, even if the minus azimuth head 112 is normal (reading the recorded signal is possible) during playback, the minus azimuth head 112 moving on the minus azimuth track 133 will not move on the track 133.
AT of the positive azimuth track 132 next to 3
F pilot signal 1321 and ATF of the positive azimuth track 134 adjacent to the front of the truck 133
Although it is possible to detect the pilot signal 1341, since the ATF sync signal 1331 of the minus azimuth track 133 is not recorded, the minus azimuth head 112 cannot detect the ATF sync signal 1331, and the conventional R-DAT could not perform tracking control.

In this way, in the conventional R-DAT, if a signal is not recorded on either the positive azimuth track or the negative azimuth track, both the positive azimuth head and the negative azimuth head are normal during playback. However, tracking control could not be performed and recorded signals could not be reproduced.

To address this problem, conventional approaches have been to make the head less likely to clog by improving the shape of the head and the magnetic material and binder of the tape, and by installing a separate CTL servo to track the head during playback even if the head is defective during recording. Measures were taken to enable control. However, these measures are not fundamental, and even if the shape of the head and the magnetic material and binder of the tape are improved, there are limits.Furthermore, if a separate CTL servo is provided, there will be problems in terms of compatibility. was to occur.

In view of the above-mentioned problems with the conventional R-DAT tracking control method, the present invention provides that even if one of the positive azimuth head or the negative azimuth head becomes defective during recording, tracking control is performed accurately and the other azimuth head is The purpose is to read and reproduce signals recorded by a head.

[Means for solving problems]

According to the present invention, there is provided a tracking control method for an R-DAT that detects ATF signals recorded by first and second azimuth heads to control tracking during playback, wherein the first and second azimuth heads Reserve AT at the location of the regular ATF pilot signal to be recorded by the head.
The F pilot signal is recorded in advance, and if the first azimuth head becomes defective during recording, the ATF sync signal of the second azimuth track is detected by the second azimuth head, and the second azimuth head is detected. An R-DAT tracking control method is provided, characterized in that tracking control is performed by detecting the preliminary ATF biloft signal recorded adjacent to the azimuth track using the second azimuth head.

[For production]

According to the R-DAT trunking control method of the present invention having the above-described configuration, a preliminary ATF pilot signal is recorded in advance at the position of the regular ATF pilot signal to be recorded by the first and second azimuth heads. be done.

Therefore, even if the first azimuth head becomes defective during recording, the second azimuth head detects the ATF sync signal of the second azimuth track, and
Tracking control can be performed by detecting a preliminary ATF biloft signal recorded adjacent to the azimuth track.

In this way, even if one of the positive azimuth head or the negative azimuth head becomes defective during recording and no signal is recorded on one azimuth track, tracking control is performed accurately to ensure that the signal recorded by the other azimuth head is not recorded. can be read and played.

〔Example〕

Hereinafter, the R-DAT tracking control method according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram for explaining an R-DAT tracking control method according to the present invention. As shown in FIG. 3A, first, preliminary ATF biloft signals 301, 302, 303, 304, and 305 are recorded on the tape 3 in advance. These preliminary ATF pilot signals 301.30
2,303,304.305 are the ATF pilot signals when the signal is normally recorded on the tape 3, that is, the regular ATF pilot signals 312, 321, 332, as is clear from the same figure (b). ,341,352
The width of the upper half of the track (0, 5) rank) of each ATF pilot signal is recorded at the position corresponding to . As shown in FIG. 6B, if the plus azimuth head 11 and minus azimuth head 12 are normal during recording, the pre-recorded preliminary ATF pilot signals 301, 302, 303, 304, 305 are overridden and the regular ATF signal 312°321.
332, 34L352 will be recorded.

For example, when the positive azimuth head 11 detects the ATF sync signal 342 of the positive azimuth track 34, the positive azimuth head 11 detects the ATF sync signal 342 of the next adjacent negative azimuth track 33 of the trunk 34.
The pilot signal 332 is detected and the track 34
ATF of minus azimuth track 35 adjacent to the front of
Pilot signal 352 is detected. That is, the positive azimuth head 11 moving on the positive azimuth track 34 receives the ATF pilot signal 332 at the negative azimuth tracks 33 and 35 adjacent on both sides.
The strength of the leakage magnetic field from the pilot signals 332 and 352 is compared, and the running speed of the tape is changed so as to match the strength of the detection signals from both the pilot signals 332 and 352. As a result, the plus 7 azimuth head 11 is tracked to be accurately traced on the plus azimuth track 34. The same applies when the minus azimuth head 12 traces the minus azimuth track.

Next, as shown in FIG. 1(c), a case will be described in which, for example, the plus 7 azimuth head 11 becomes defective during recording and a signal cannot be recorded on the plus azimuth tracks 31, 33, 35. Here, the minus azimuth head 12 has a width of 1.5 tracks (approximately 20.4 μm), and if the plus azimuth head 11 becomes defective, the width of the plus azimuth head 11 becomes oversized by 0.5 tracks. Since it will not be bi-written, the negative azimuth track 31a.

Signals are recorded at 33a and 35a with a width of 1.5 tracks. Pre-recorded pre-@ATF pilot signals 302 and 304 remain between the minus azimuth tracks 31a and 33a and between the minus azimuth tracks 33a and 35a, respectively. These preliminary ATF pilot signals 3
02 and 304 are recorded at positions corresponding to the regular ATF pilot signals 321 and 341 that should be recorded in the plus azimuth tracks 32 and 34 when the plus azimuth head 11 is normal. Therefore, for example, when the minus azimuth head 12 detects the ATF sync signal 331a of the minus azimuth track 33a, the minus azimuth track 2 detects the regular ATF pilot signal 3 next adjacent to the track 33a.
Preliminary ATF pilot signal 30 recorded at position 21
2 is detected, and furthermore, a preliminary ATF pyro throat signal 304 recorded at the position of the regular ATF pilot signal 341 adjacent to the front of the track 33a is detected.

Then, the negative azimuth head 12 moving on the negative azimuth track 33a is adjacent to the pre-IAT on both sides.
Trunking will be controlled by comparing the strengths of the stray magnetic fields from F pilot signals 302 and 304.

Furthermore, as shown in FIG. 1(d), a case will be described in which, for example, the minus azimuth head 12 becomes defective during recording and signals cannot be recorded on the minus azimuth tracks 32 and 34. Here, the plus azimuth head 11 also has a width of 1.5 tracks like the minus azimuth head 12 described above, and if the minus azimuth head 12 becomes defective, the plus azimuth tracks 32a and 34a will have a width of 1.5 tracks. The signal will be recorded with a width equal to the track width. And plus azimuth track 3
2a and the next positive azimuth track, between the positive azimuth tracks 32a and 34a, and between the positive azimuth track 34a and the previous positive azimuth track, there are pre-recorded preliminary ATs.
F pilot signals 301, 303 and 305 will remain. These preliminary ATF pilot signals 30
1° 303 and 305 are negative azimuth head 1
If 2 is normal, negative azimuth track 31.33
and 35 are recorded at positions corresponding to the regular ATF pilot signals 312, 332 and 352 to be recorded. Therefore, for example, when the positive azimuth head 11 detects the ATF sync signal 342a of the positive azimuth track 34a, the positive azimuth head 11 detects the next normal ATF sync signal 342a of the positive azimuth track 34a.
Reserve AT recorded at the position of pilot signal 332
F pilot signal 303 is detected, and furthermore, the normal ATF pilot signal 3 adjacent to the front of the track 34a is detected.
Preliminary ATF pilot signal 30 recorded at position 52
5 is detected. And the positive azimuth track 34a
Tracking is controlled by comparing the strength of the leakage magnetic field from the ATF pilot signals 303 and 305 adjacent to both sides of the positive azimuth head 11 moving above.

FIG. 2 is a diagram showing an example of a head configuration for realizing the R-DAT tracking control method of the present invention. Figure (a)
As shown in FIG. 1 and (b), in an example of the head configuration for realizing the R-DAT tracking control method of the present invention, the pilot signal recording heads 13 and 14 are
．． The plus and minus azimuth heads 11 and 12 have a width d for 5 tracks (approximately 6.8 μm) and a width d for 1.5 trunks (approximately 20.4 μm).
The rotating drum l moves forward by an angle of 90″ against
It is located in Furthermore, the upper ends of the pilot signal recording heads 13 and 14 are made to coincide with the upper ends of the plus and minus azimuth heads 11 and 12.

FIG. 3 is a diagram showing signals recorded on a tape by the head configuration of FIG. 2.

First, as shown in FIG. 3(a), an IBG signal (Inter Block Gap: for example, a signal with a frequency of 1 and 568 MHz) 353a is applied to the minus azimuth track 35a by the minus azimuth head 12.
ATF sync signal 351a, erase signal (Era
se: For example, a signal with a frequency of 1.568MHz)
354a, ATF by O soto signal 352a and [
The BG signal 355a is recorded with a width of 1.5 tracks. Here, 0 . . . in the center of the ATF pilot signal 352a
A preliminary ATF pilot signal 305 is recorded in advance by the pilot signal recording head 13 at a position of five track widths. Next, as shown in FIG. 3B, the pilot signal recording head 14 records the IBG signals 3041. Pre-@ATF pilot signal 304. Erase signal 3042 and IBG signal 304
3 is recorded with a width of 0.5 track.

Furthermore, if the positive azimuth head 11 is normal,
As shown in the same figure (c), plus azimuth head 1
1, the IBG signal 3 is sent to the positive azimuth track 34a.
43a, ATF pilot signal 341a, erase signal 344a, ATF sync signal 342
a. Erase signal 345a and IBG signal 346
a is recorded with a width of 1.5 tracks. At this time, 0, 5 recorded by the pilot signal recording head 14
The track width signal is overridden by the plus azimuth head 11, and the minus azimuth track 35a with a 1.5 track width is overridden by the width of the upper 0.5 track to become the minus azimuth track 35 with a one track width. At this time, if the plus azimuth head 11 is defective and a signal cannot be recorded on the plus azimuth track 34a, the recording signal shown in FIG. 3(b) is held, and if the plus azimuth head 11 continues to be defective, A signal as shown in FIG. 1(c) will be recorded. Even when playing back a tape on which a signal like the one shown in FIG. It is as follows.

Then, the positive azimuth head 11 is normal and as shown in Fig. 3 (c).
) is recorded, the pilot signal recording head 13 records a signal of 1.5 as shown in FIG.
IBG signal 3031° Erase signal 3 next to the minus azimuth track 34a of track width
032. Reserve ATF pilot signal 303 and IBG
A signal 3033 is recorded with a width of 0.5 track.

Furthermore, when the minus azimuth head 12 is normal, as shown in FIG.
, erase signal 334a, ATF pilot signal 332a, and IBG signal 335a are recorded with a width of 1.5 trunks.At this time, the 0.5 track width recorded by the pilot signal recording head 13 is recorded. The signal is overridden by the minus azimuth head 12, and the 1.5 track width plus azimuth track 34a is overridden by the width of the upper 0.5 track to become the 1 track width plus azimuth track 34. At this time, The negative azimuth head 12 is defective.
If a signal cannot be recorded on the minus azimuth track 33, the recorded signal shown in FIG.
A signal as shown in FIG. 1(d) will be recorded. Even when playing back a tape on which a signal like the one shown in FIG. It is as follows.

In the embodiment described above, the pilot signal recording head 13 (14) is the azimuth head 11- (1
2), and is arranged on the rotating drum 1 at a position advanced by an angle of 90° with respect to 2), and at a position where the upper end of the pilot signal recording head 13 (14) coincides with the upper end of the azimuth head 11 (12). The preliminary ATF pilot signals 301, 303, 305 are placed at the positions of the regular ATF pilot signals 312, 332, 352 (321, 341) to be recorded by the azimuth head IH12).
It can be provided at any position on the rotating drum 1 as long as it is possible to record (302, 304) in advance.

Also, to the pilot signal recording head 13 (14)
- The rad width does not have to be the width of 0.5 trunks as long as it satisfies the above-mentioned conditions and does not overlap the track to be written first.

〔Effect of the invention〕

As described above in detail, the R-DAT tracking control method according to the present invention allows even if either the positive azimuth head or the negative azimuth head becomes defective during recording,
Tracking control can be performed accurately, and the signal recorded by the other azimuth head can be read and reproduced.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the tracking control method of the R-DAT according to the present invention, FIG. 2 is a diagram showing an example of a head configuration for realizing the tracking control method of the R-DAT according to the present invention, and FIG. 2 is a diagram showing signals recorded on a tape by the head configuration of FIG. 2, and FIG. 4 is a diagram for explaining a conventional R-DAT tracking control system. (Explanation of symbols) 1...Rotating drum, 2...Fixed drum, 3...Tape, 11...Plus azimuth head, 12...Minus azimuth head, 13, 14...Biloft signal recording head, 3L3
1a, 33° 33a, 35, 35a... Minus azimuth track, 32, 32a, 34, 34a... Plus azimuth track, 301.302° 303.304, 305... Reserve ATF pilot signal, 31L3L1a, 322 , 322a, 331°33
1a, 342.342a, 351, 351a=
ATF sink signal, 312.312a, 321,3
21a, 332° 332a, 341, 341a, 352
, 352a = A TF pilot signal.

Claims (1)

[Scope of Claims] 1. A tracking control method for R-DAT that detects ATF signals recorded by first and second azimuth heads to control tracking during playback, comprising: A preliminary ATF pilot signal is recorded in advance at the position of the regular ATF pilot signal to be recorded by the azimuth head of the azimuth head, and if the first azimuth head becomes defective during recording, the ATF sink of the second azimuth track is recorded. A signal is detected by the second azimuth head, and the preliminary ATF pilot signal recorded adjacent to the second azimuth track is detected by the second azimuth head to perform tracking control. R-DAT tracking control method. 2. The preliminary ATF pilot signal is recorded by first and second pilot signal recording heads corresponding to the first and second azimuth heads, and the first and second pilot signal recording heads include: 2. The method according to claim 1, wherein said first and second azimuth heads are respectively disposed on rotating drums provided with said azimuth heads. 3. The first and second pilot signal recording heads have a width of 0.5 track, and are angled at 90° with respect to the first and second azimuth heads, which have a width of 1.5 track. Claim 2, wherein the first and second pilot signal recording heads form an angle, and the upper ends of the first and second pilot signal recording heads coincide with the upper ends of the first and second azimuth heads. method. 4. Claim 1, wherein the preliminary ATF birod signal is recorded on the first and second azimuth tracks together with the IBG signal and erase signal located before and after the preliminary ATF pilot signal. The method described in section.