WO1996010822A1

WO1996010822A1 - Magnetic recording/reproducing device having high-speed reproduction mode

Info

Publication number: WO1996010822A1
Application number: PCT/JP1995/001991
Authority: WO
Inventors: Naozumi Sugimura; Harushige Nakagaki; Yasunori Ohara; Nobutaka Amada; Takao Arai; Masato Sano
Original assignee: Hitachi, Ltd.
Priority date: 1994-09-30
Filing date: 1995-09-29
Publication date: 1996-04-11
Also published as: KR960706165A; KR100233202B1; DE19581346C2; DE19581346T1

Abstract

A magnetic recording/reproducing device provided with a recording device which records signals on a magnetic tape with a rotary head and a reproducing device having a standard reproduction mode in which signals are reproduced at a standard tape speed and a high-speed reproducing mode in which signals are reproduced at a prescribed tape speed faster than the standard tape speed. A recording signal processing section processes digital signals to be recorded so that the data of the digital signals to be reproduced in the high-speed reproducing mode may be dispersedly recorded at prescribed positions on a plurality of prescribed tracks. In the high-speed reproducing mode, the data to be reproduced at the high-speed are recorded so that the data can be arranged along the scanning locus of the rotary head on the magnetic tape. A mark adding section generates marks corresponding to the positions of the tracks on which the data of digital signals to be reproduced in the high-speed reproducing mode are recorded and adds the marks to control signals. A control head records the control signals to which are added the marks corresponding to the positions of the tracks on a magnetic tape when the recording device records signals or reproduces the control signals to which the marks are added when the reproducing device reproduces the signals. A mark detecting section detects the marks from the reproduced control signals. A phase comparing section detects the phase differences between the marks and a reference signal synchronizing with the rotation of the rotary head. A capstan servo section controls the speed of the magnetic tape so that the phase difference may be a prescribed reference value.

Description

Description Magnetic recording / reproducing device with high-speed reproduction mode

The present invention relates to a digital VTR for recording / reproducing a digital video signal using a rotating magnetic head, and particularly to a tracking control method at the time of variable speed reproduction for reproducing at an arbitrary speed higher than a normal reproduction speed. is there.

Background art

With the rapid progress of digital technology in recent years, various information has been digitized, and it is becoming possible to store, transmit, and reuse it.

In particular, audio signals have been digitized at an early stage, and digital audio products such as compact disks (CDs) have become a well-known technology.

On the other hand, the digitization of video signals is also progressing in the field of broadcasting and communication, and digital broadcasting is about to be put to practical use in the United States and other countries in conjunction with advances in image compression technology.

Against this background, digital VTRs are also being developed. For example, digital recording is being studied using a so-called VHS VTR, which is widely used as a home VTR. When recording digital video signals on a home-use VTR such as the VHS system, the image compression technology must be relied on because of the recording quality, recording time, and tape consumption.

As an image compression technique, for example, there is a Moving Picture Experts Group (MPEG) standardized by ISO. Many image compression technologies, such as the MPEG method, use the correlation between frames to achieve a high compression ratio without degrading image quality. This takes advantage of the characteristic that the image hardly changes in consecutive frames, and encodes only the difference between two frames to greatly reduce the amount of data. On the other hand, there is a drawback that only continuous frames of images can be reproduced. When performing variable-speed playback on image data recorded on a VTR, the rotating magnetic head plays back data across tracks, so image data played back by variable-speed playback is No. For this reason, variable-speed playback could not be performed when the compressed video was recorded on a VTR.

For example, "FAST SCAN TECHNOLOGY FOR" is a recording and playback method that uses image compression by the MPEG method and also supports variable speed playback.

A method such as "DIGITAL VIDEO TAPE RECORDERS (IEEE Transactions on Consumer Electronics Vol. 39, No. 3, AUGUST 193 33)" has been proposed.

In this method, the image for variable speed playback is placed at a specific position on the magnetic tape that matches the scanning locus of the playback head according to the tape speed so that the image can be restored even during variable speed playback. Data is recorded separately and separately. If intra-frame compression is performed overnight for variable-speed playback, video can be restored from one frame of data for variable-speed playback.

FIG. 9 shows an example of data arrangement on a magnetic tape when recording is performed by this method. In FIG. 9, reference numeral 104 denotes a magnetic tape, reference numeral 402 denotes a scanning trajectory of a rotating magnetic head during normal reproduction, reference numeral 4003 denotes a scanning trajectory of a rotating magnetic head during triple speed reproduction, and reference numeral 404 Is the scanning locus of the rotating magnetic head at 9x speed playback, 405 is the recording area for video data for normal playback, 406 is the recording area for video data for 3x playback, and 407 is 9x playback speed The recording area for evening video data, and 408 is a control track.

At the time of triple speed playback, the rotating magnetic head performs playback across three tracks as indicated by 403, so that the video data for triple speed playback is arranged at a position such as 406. Also, since the scanning locus of the rotating magnetic head during 9x speed reproduction is as shown in 404, if the 9x speed reproduction video data is placed at the 407 position, the 9x speed reproduction data can be reproduced. Is possible.

When performing variable speed playback using the conventional method as described above, there are the following problems.

That is, in the above-mentioned conventional example, since the video data for variable-speed reproduction is recorded on a specific track, the rotating magnetic head accurately records this track during variable-speed reproduction. Although it is necessary to control the scanning so as to perform scanning, no control means has been considered for this.

In a conventional VHS type VTR, a control signal is recorded on a control track for tracking control, and the position of the reproduction track is detected based on the control signal during reproduction. However, since control for scanning a specific track during variable-speed playback is not taken into consideration, it is difficult to detect the position of the variable-speed playback track when the above data arrangement is performed. Images cannot be played correctly.

Disclosure of the invention

A magnetic recording / reproducing apparatus according to the present invention comprises: a recording apparatus for recording a signal on a magnetic tape by a rotating head; a standard reproducing mode for reproducing a signal at a standard tape speed; and a predetermined reproducing mode higher than the standard tape speed. A reproduction device having a high-speed reproduction mode for reproducing a signal at a tape speed. The recording signal processing unit processes the digital signal to be recorded so that the data of the digital signal reproduced in the high-speed reproduction mode is dispersedly recorded at predetermined positions on a plurality of predetermined tracks. In the high-speed playback mode, the data for high-speed playback is recorded so as to be arranged at a position along the scanning locus of the rotating head on the magnetic tape. The mark adding section generates a mark corresponding to the position of the track where the digital signal data reproduced in the high-speed reproduction mode is recorded, and adds the mark to the control signal. The control head records a control signal with a mark corresponding to each track position on a magnetic tape when a signal is recorded by a recording device, and a mark when a signal is reproduced by a reproducing device. Plays the control signal with. The mark detector detects a mark from the reproduced control signal. The phase comparator detects a phase difference between the mark and a reference signal synchronized with the rotation of the rotary head. The capstan servo unit controls the traveling speed of the magnetic tape so that the phase difference becomes a predetermined reference value.

In the high-speed reproduction mode of the magnetic recording / reproducing apparatus according to the present invention, a plurality of different speeds may be set. In a reproduction mode called “variable speed reproduction” in the specification of the present application, a plurality of different high-speed running speeds are set, and a desired speed can be arbitrarily selected (variable) from a plurality of set speed values. Since the information on the recording start position of the variable speed reproduction data is recorded as a mark added to the control signal, the recording start position of the variable speed reproduction data can be known. During variable speed reproduction, the rotary magnetic head scans a predetermined track on which variable speed reproduction data is recorded by comparing the phase of the mark detection timing with the reference signal and controlling the phase of the hub.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram of an embodiment of a magnetic recording / reproducing apparatus according to the present invention.

FIG. 2 is a block diagram showing a specific configuration of the mark adding unit.

FIG. 3 is a waveform timing chart for explaining the operation of the mark adding unit.

FIG. 4 shows a recording pattern of a track reproduced in the high-speed reproduction mode.

FIG. 5 is a block diagram showing a specific configuration of a mark detection unit.

FIG. 6 is a waveform timing chart for explaining the operation of the mark detection unit.

FIG. 7 shows another recording pattern of a track reproduced in the high-speed reproduction mode. Fig. 8 shows another recording pattern of a track that is played back in the high-speed playback mode. Figure 9 shows the recording pattern on a magnetic tape in a conventional digital VTR.

FIG. 10 is a block diagram illustrating a configuration of a specific example of a tracking error detection unit. FIG. 11 shows a recording pattern of a track reproduced in the 4 × and 8 × speed modes. Fig. 12 is a schematic diagram of a part of the track played back in the high-speed playback mode. FIG. 13 is a waveform timing chart for explaining the operation of the tracking error detection unit in FIG.

FIG. 14 is a block diagram illustrating another configuration example of the tracking error detection unit.

FIG. 15 is a block diagram of another embodiment of the magnetic recording / reproducing apparatus according to the present invention. FIG. 16 is a block diagram showing a configuration of a specific example of a tracking error detection unit in the embodiment of FIG.

Figure 17 is a schematic diagram that shows a part of the track that is played back in the high-speed playback mode. FIG. 18 shows the characteristics of the output signal of the tracking error detector of FIG.

FIG. 19 is a block diagram of still another embodiment of the magnetic recording / reproducing apparatus according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram showing one embodiment of a tracking control device according to the present invention. In FIG. 1, 101 is a supply reel for supplying a magnetic tape, 102 is a rotating magnetic head for recording and reproducing signals, 103 is a drum on which a rotating magnetic head is arranged, and 104 is a signal. Magnetic tape for recording, 105 is a control head for recording and reproducing control signals, 106 is a hubstank for running the magnetic tape, 107 is a pinch roller, and 108 is a take-up for winding the magnetic tape Reel, 109 is switching means, 110 is a reproduction signal processing unit that performs reproduction signal processing, 111 is a recording signal processing unit that performs recording signal processing, and 112 is a reference signal that generates a reference signal Generating unit, 1 13 is a mark adding unit that adds a mark to the control signal, 1 14 is a switching switch, 1 15 is a capstan servo circuit that controls the rotation of the capstan, and 1 16 is a reference signal and playback. Phase comparison section that compares the phase with the control signal, 1 1 7 Is a mark detector that detects a predetermined mark from the reproduced control signal, 118 is a system controller that commands the playback speed, 119 is a signal output terminal, 120 is a signal input terminal, and 20 is a signal input terminal. This is a tracking error detector.

First, the operation at the time of recording the digital VTR will be described.

A digital video signal to be recorded by the digital VTR is input to the signal input terminal 120. The digital video signal has been subjected to image compression by, for example, the MPEG system, and is received via satellite broadcasting, cable television, or the like.

The digital video signal is divided by the recording signal processing circuit 111 into blocks of a predetermined length. A block address indicating the address of the block on the tape and an error correction code for correcting an error during reproduction are added to the data of each block. This is because even when the rotating magnetic head 102 partially reproduces data across the track, it is possible to reproduce data in units of blocks. Similarly, data for variable-speed reproduction is added with a block address and an error correction code in units of blocks, and is inserted at a predetermined position on the track as shown in FIG. As the variable speed data, data obtained by performing compression on a frame basis may be stored in a memory, and the data may be divided into a plurality of predetermined tracks and output. After that, the data of each track is modulated and converted into a signal suitable for recording on the magnetic tape 104. Under these controls, the signal for each track on which the predetermined processing has been performed by the recording signal processing circuit 111 is supplied to the rotating magnetic head 102 synchronized with the reference signal, and the magnetic tape Recorded in 104.

The rotating magnetic head 103 is controlled by a drum servo (not shown) at a rotation speed of 180 O rpm, and its rotation phase is also changed to a reference signal 112 (3 O Hz) and a drum rotation. By the phase comparison control using the rotation pulse or the like, the reference signal 112 is controlled so as to have a predetermined phase relationship with the reference signal 112. In addition, the tape speed is controlled to a predetermined speed by a capstan button, and by a phase comparison control between a signal obtained by appropriately dividing the capstan FG signal and a reference signal 112 (not shown), The running phase is also controlled. These controls are no different from the conventional analog VHS and VTR.

On the other hand, on the magnetic tape, a control track 408 for recording a control signal is provided in a longitudinal direction of the magnetic tape, separately from a video signal track for recording a video signal. The control signal is recorded by the control head 105, which is a fixed head, and is used for head tracking control during reproduction.

In the conventional analog VHS and VTR, the 30 Hz reference signal 112 used for the phase control of the rotating drum is recorded as a control signal on a magnetic tape with a fixed head. At the time of reproduction, tracking control is performed so that the head scans the recording track correctly by phase comparison control between the timing at which the control signal is reproduced and the reference signal 112.

In the digital VTR according to the present invention, since the variable speed reproduction track to be scanned by the rotating magnetic head at the time of variable speed reproduction is predetermined, a signal for tracking control for the variable speed reproduction track is also required. . Therefore, in Fig. 1, a mark for identification information is added to the control signal synchronized with the first track at which recording of variable speed playback data starts by the mark addition unit 113, and this is used as a tracking control signal during variable speed playback. I used it.

The recording signal processing circuit 1 1 1 1 is arranged so that the variable speed reproduction data is recorded at a predetermined position on the track, ie, the normal reproduction data 4 05 shown in FIG. 06 and 9x speed playback data 4 07 Recorded data is composed and supplied to the rotating magnetic head. Thus, the pattern of the recording track is as shown in FIG.

At the same time, the recording signal processing circuit 111 is a variable speed playback track located at the head position of the track for variable speed playback, that is, at the bottom end of the tape in terms of the head scanning trajectories 400 and 404 in FIG. A mark addition command is supplied to the mark addition circuit 113 at each scan timing of the head for recording the data 406 and 407. The mark adding circuit 113 works to add a predetermined mark to the reference signal in response to the mark adding command, whereby the control head has a head track of a data group forming a variable speed playback track. A control signal with a mark is output at each timing of recording a mark. Hereinafter, the operation of the mark adding circuit 113 will be described using a specific embodiment shown in FIG.

In FIG. 2, 201 is a reference signal input, 202 is a mark addition signal input, 203 is a first pulse generator, 204 is a second pulse generator, 205 is a switching switch, Reference numeral 206 denotes a control signal output, reference numeral 206 denotes an output of the first pulse generator, and reference numeral 208 denotes an output of the second pulse generator.

The output signal of the reference signal generator 112 is 30 Hz (period t = 33.3 ms) and the duty ratio is 50%. This reference signal is input to the input terminal 201. The first pulse generation circuit 203 generates a pulse having a pulse width of 10 ms in accordance with the rise of the reference signal (207). Similarly, the second pulse generating circuit 204 is configured to generate a pulse having a pulse width of 5 ms from the rise of the reference signal (208). The switching switch 205 switches between the reference signal 201, the output 207 of the first pulse generation circuit, and the output 208 of the second pulse generation circuit in accordance with the mark addition control signal 202. The output 207 of the first pulse generation circuit corresponds to a duty ratio of 30%, and the output 208 of the second pulse generation circuit corresponds to a duty ratio of 15%. As a result, as shown in the timing chart of FIG. 3, a control signal 206 having a duty ratio modulated according to the mark control signal 202 can be obtained, and the reference signal with the mark added thereto is the switching switch 111. The signal is transmitted to the control head through 4 and recorded on the magnetic tape as a control signal.

By the above processing, the variable speed playback data is recorded on the magnetic tape as shown in FIG. A control signal with a mark added in synchronization with the first track at the start of the evening recording is recorded. In the example of the track pattern shown in FIG. 4, the first pulse output is used as a mark b for triple speed, and the output of the second pulse generation circuit is used as a mark c for triple speed and ninth speed.

Next, the operation at the time of the variable speed reproduction will be described with an example of the triple speed.

When the variable speed playback is commanded, the system controller 118 issues a command to the capstan boss 115 so that the capstan 106 rotates at three times the speed of recording. Tape 104 runs at three times the speed. At this time, the recorded control signal is reproduced from the control head 105 at three times the speed. The control signal is supplied to the mark detection unit 117 through the switching switch 114.

The mark detector 1 17 detects a mark corresponding to the playback speed from the marks added to the control signal during recording. In 3x speed playback, marks corresponding to 3x speed tracks are detected.

Here, the operation of the mark detection unit 117 will be described below.

FIG. 5 shows a specific example of the mark detection unit 1 17. In the figure, 501 is a control signal input, 502 is a speed designation signal input, 503 is a pulse generation unit, 50 0 4 is a latch circuit, 505 is a mark detection signal output, and 506 is an output of a pulse generator.

The control signal reproduced from the control head is input to the control signal input terminal 501. Further, a speed designation signal from the system control unit 118 is input to the speed designation signal human input terminal 502.

At 3x speed, the control signal is also played back at 3x the speed of normal playback. At this time, the frequency of the control signal 501 is 90 Hz. Here, the duty ratio of the control signal recorded for the mark b for 3 × speed reproduction is 30%, and the duty ratio of the control signal for the mark c for 3 × and 9 × speed reproduction is 1 Assuming 5%, the H level period of the control signal in the marked part is about 3.3 ms (b) and 1.6 ms (c), respectively. Since the control signal without the mark recorded has a duty ratio of 50%, the H level period is about 5.5 ms. Therefore, by examining the part where the H level period of the control signal is shorter than 4 ms, for example, The peaks b and c can be detected.

Fig. 6 shows the operation waveforms. The pulse generation circuit 503 outputs 4 ms from the control signal 501 reproduced from the head 105 input to the control signal input terminal. A pulse is generated (506). The latch 504 latches the control signal 501 at the falling edge of the pulse 506. For a normal control signal without a mark, the H level period is longer than 4 ms, so the latched result (505) is always H level. On the other hand, in the mark portions b and c, the H level period of the control signal 501 is short and the control signal falls before the pulse 506 described above. The positions of the marks b and c can be detected from the control signal 501.

The phase comparator 1 16 compares the phase of the 30 Hz mark detection signal generated by the mark detection section 1 17 with the reference signal 1 1 2, and adjusts the capstan motor so that the comparison error becomes a predetermined value. (Not shown).

As a result, the tracking phase of the rotating magnetic head 102 scans a predetermined track 403 on which data for triple-speed reproduction is recorded.

The data for triple-speed reproduction on the magnetic tape is reproduced by the rotating magnetic head 102. The data reproduced by the rotating magnetic head 102 is input to the reproduction signal processing circuit 110 through the switching switch 109, and is output to the signal output terminal 119 as video data by predetermined processing. .

In the above embodiment, since the start positions of the variable speed reproduction tracks of 3 × and 9 × overlap, the mark c indicates two types of variable speed reproduction tracks. For example, as shown in FIG. 7, by arranging the tracks for variable-speed playback at different playback speeds, one mark can correspond to one playback speed. In this case, two pulse generators may be provided for mark detection so that each mark can be detected independently, and only a mark having a predetermined width may be detected.

By the way, in the recording as shown in Fig. 4, if the position of the 9x speed mark c is known, the position of the 3x speed mark b can be obtained from the arrangement relationship of the tracks at both playback speeds. May be. FIG. 8 shows this embodiment. It is. By measuring the number of control signals after detecting mark C,

It is easy to identify the starting position of the 3x speed track. In addition, even if the arrangement of the tracks for variable speed playback changes, it is possible to obtain the start position of each track by calculation if there is at least one mark if it is known.

In the above example, variable speed playback at 3 × speed and 9 × speed has been described as an example, but the present invention is not limited to these, and data for a variable speed playback track at an arbitrary playback speed is recorded. It is needless to say that the present invention can be used for tracking control of a magnetic table which has been performed, and also for tracking control of variable speed reproduction not only in the forward direction but also in the reverse direction.

Furthermore, in the above example, the duty ratio modulation of one control signal is used as a mark recording method. However, the present invention is not limited to this. For example, a plurality of continuous control signals may have the same duty ratio. It is also possible to identify the mark by the ratio modulation and the number of marks, or to record the mark by using a pattern in which control signals having different duty ratios are combined.

As described above, according to the present invention,

When performing variable-speed playback of a magnetic tape in which information for variable-speed playback at an arbitrary speed higher than the normal playback speed is dispersedly recorded at track positions according to the scanning trajectory of the rotating head, the information for variable-speed playback is used. It is possible to provide a tracking control device capable of accurately tracking a variable speed reproduction track on which data is recorded.

Next, a second embodiment of the magnetic recording / reproducing apparatus according to the present invention will be described with reference to other drawings. In the first embodiment, the rotation head accesses the track on which the variable speed reproduction data block is arranged by detecting the mark in the control signal. The fixed position of the control head 105 is manufactured to be the specified value with respect to the rotation phase of the rotating head 102. ), The position of the control head 105 varies between products or different models. This variation appears as a detection error, that is, a tracking error when a variable speed reproduction track is determined by detecting a mark. In the second embodiment, even if the recording position of the mark and the position of the track for variable speed reproduction corresponding to the mark vary depending on the recording / reproducing apparatus, the track for variable speed reproduction and the reproduction speed of the track for variable speed reproduction are different. An error from the rotational phase of the head is detected by the tracking error detector 20 in FIG. 1, and the speed of the magnetic tape is adjusted so that the head always traces accurately to the desired variable-speed playback track. Adjust to correct head tracking deviation at variable speed. Hereinafter, the tracking correction operation will be described by taking as an example a case where the magnetic head is accurately tracked to the center of the track 4003 for quadruple speed reproduction in FIG. This control is performed by changing the reference value of the control of the phase comparison unit 116 that compares the phase of the mark detection signal and the reference signal, and is performed to enable compatible reproduction between VTRs. .

In Fig. 11, the hatched portion like 401 shows data for 4x speed playback, the shaded portion like 402 shows data for 8x speed playback, and 4003 shows 4x speed playback. Reference numeral 404 indicates a track for 8 × speed reproduction. In the figure, reference numeral 405 denotes a control track. The control signal recording position of a 50% duty ratio control signal, which outputs the reference signal as it is, is a, and the duty ratio output from the pulse generation circuit 203 is 30%. The recording position of the signal is indicated by b, and the recording position of the control signal with a duty ratio of 15% output from the pulse generation circuit 204 is indicated by c.

The control signal indicating the recording position of the track is recorded by the control head 105, but this control head 105 is not necessarily installed in the same position in all VTRs. . Therefore, the recording position of the control signal with respect to the recording position of the track when considering compatible reproduction has a difference for each recorded VTR.

In the VTR capable of recording and reproducing the digital signal of the present invention, the recording position of the track for variable speed reproduction is detected by the mark added to the control signal. Therefore, if there is a problem as described above, the recording position of the mark does not accurately indicate the recording position of the track for variable speed reproduction, and accurate tracking of the magnetic head cannot be realized for compatibility. become.

In order to solve such a problem, it is only necessary to have an adjustment device that corrects the reference point of the phase comparator 116 according to the output from the tracking error detection unit 20 during reproduction. This correction is performed, for example, in the order of the mark signal detected by the mark detection unit 117. This can be realized by shifting the phase or the phase of the phase reference signal from the reference signal generator 112, or by giving an offset to the output of the phase comparator 116.

In the VTR capable of digital recording and reproduction according to the present invention, the tracking error detection unit 20 shown in FIG. 1 detects a required phase shift amount according to the tracking error, and performs tracking correction according to the result. are doing.

Hereinafter, the operation of the tracking error detecting section 20 will be described using a specific embodiment shown in FIG. In the figure, reference numeral 701 denotes a speed command input terminal for inputting a speed command output from the system control unit 118, and 702 and 703 input a block address output from the reproduction signal processing unit 110. This is a block address input terminal for inputting the track number of the block currently being scanned by the magnetic head to terminal 702 and the block number to terminal 703. 704 is a ROM that stores the reference block address. 705 is a comparison circuit that compares the block number output from the ROM 704 with the block number output from the playback signal processing circuit 8. 06 is the sampling operation when the track number output from the ROM 704 matches the track number output from the playback signal processing unit 110, and the operation is held otherwise. This is a sample & hold circuit that switches to operation. Reference numeral 707 denotes a tracking error output terminal for outputting a comparison result from the comparison circuit 705.

The tracking error detection unit 20 shown in FIG. 10 detects the tracking error of the magnetic head with respect to the variable speed reproduction track based on the track number and the block number supplied from the reproduction signal processing unit 110. It has a configuration.

FIG. 12 is a drawing of a part of the recording pattern on the magnetic tape 104 of FIG. 11 and illustrating the principle of error detection by the tracking error detection unit 20 of FIG. In the figure, reference numerals 800, 800, and 803 denote the scanning trajectories of the magnetic head 102, and the scanning trajectory 8001 is the quadruple speed shown in FIG. 11 by the magnetic head 102. The trajectory when scanning the center of the reproduction track 403 is shown. The alphanumeric characters shown on the track indicate the block address of each track, such as (track number, block number). When the magnetic head reaches the track of track number 4 in the scanning trajectory 8001, the block number is 27. Since the signal processing circuit 7 determines the arrangement of data for variable-speed playback according to a fixed algorithm based on the block address, the block numbers 27 are predetermined and the ROM block is used as a reference block number. It can be stored in a storage device such as. Assuming that 800 and 803 are the actual scanning trajectories of the magnetic head, the block numbers when arriving at the track of track number 4 in these scanning trajectories are 30 and 22 respectively. The difference between the value and the above-mentioned reference block number is 3 and 15, respectively, and these values are values proportional to the phase difference between the reference path and the scanning trajectory 8001.

As described above, the relationship between the track number and the block number to be reproduced when the magnetic head scans the center of the track 4 × 4 for 4 × speed reproduction is stored in the ROM 704 in advance, and the reference block By comparing the head address with the actually reproduced block address, it is possible to detect a tracking deviation of the magnetic head from the track 4003 for the quadruple speed reproduction.

FIG. 13 shows the operation waveforms when the magnetic head scans along a locus such as a scanning locus 803. FIGS. (A) and (B) show block addresses output from ROM 704, and show a state where track number 4 and block number 27 are output as reference block addresses during quadruple speed playback. ing. FIGS. 7C and 7D show block addresses output from the reproduction signal processing unit 110, and show the addresses of the blocks currently being scanned by the magnetic head. FIG. 11E shows the operation of the sample & hold circuit 706, and FIGS.

When the track numbers shown in (C) match, the operation switches to the sampling operation, and the difference between the two block numbers (B) and (D) output from the comparison circuit 705 is sampled. The sample & hold circuit 706 immediately switches to the hold operation, and the difference 15 between the two block numbers is output from the tracking error detecting means 20 (FIG. 13 (F)).

Since the sign of the tracking error signal is negative, it can be seen that the scanning trajectory 803 leads the scanning trajectory 801 which is the reference scanning trajectory. This indicates that the scanning trajectory 803 is shifted to the right (opposite to the tape advancing direction) with respect to the scanning trajectory 801. In other words, the mark recording position is 4x speed playback It is shifted to the right with respect to the recording position of the recording track. Using the tracking error signal, the phase of the mark signal reproduced by the mark detection unit 117 or the phase of the phase reference signal of the reference signal generator 112 is shifted using this tracking error signal. By giving an offset to the output of the phase comparator 116, it is possible to control the magnetic head to accurately scan the center of the track 403 for quadruple speed reproduction.

It should be noted that a specific example of the mark detection unit 117 shown in FIG. 5 detects the mark b and the mark c which are marks corresponding to the quadruple-speed reproduction track during quadruple-speed reproduction in the high-speed mode. However, in order to detect only the mark c corresponding to the 8 × -speed playback track during 8 × -speed playback in the high-speed mode, the “H” level of the latch pulse output from the pulse generation circuit 503 in FIG. It can be realized by changing the period as follows.

Since the cycle of the control signal reproduced at 8x speed reproduction in the high-speed mode is 4.2 msec, the level period at mark a is 2.1 msec corresponding to a 50% duty ratio. The “H” level period in b is 1.3 msec, which corresponds to a duty ratio of 30%, and the level period at mark c is 0.6 msec, which corresponds to a duty ratio of 15%. It is. At this time, if the period of the latch pulse output from the pulse generation circuit 503 is set to, for example, 1.0 msec, it is possible to detect only the mark c at the time of 8 × speed reproduction in the high-speed mode.

In addition, the detection of marks corresponding to the 8x and 16x speed playback tracks in the medium speed mode and the marks corresponding to the 16x speed and 32x speed playback tracks in the low speed mode are also performed in the same manner as described above. This can be dealt with by changing the period of the latch pulse output from the generation circuit 503.

Further, in the second embodiment, in the operation of the tracking error detection unit 20 shown in FIG. 13, the force of fixing the track number of the track for comparing the block number to one specific track number, There is no particular limitation, and tracking error signals can be detected in a plurality of tracks as necessary.

By the way, in one specific embodiment of the tracking error detection unit 20 shown in FIG. The tracking deviation of the magnetic head from the track for variable-speed playback is detected by using the relationship between the track number of the block currently scanned by the magnetic head and the block number. The method of detecting the tracking error is not limited to this. FIG. 14 shows another specific embodiment of the tracking error detecting section 20. In the figure, reference numeral 700 denotes a speed command input terminal for inputting a speed command output from the system control unit 118, and reference numeral 700 denotes a magnetic head output from the reproduction signal processing unit 110 which is currently scanned. Track number input terminal for inputting the track number of the current block, 703 is a head switching signal input terminal for inputting a head switching signal for switching magnetic heads, and 724 is a track number and magnetic ROM that stores the relationship between the head scan times, 725 is a comparison circuit that compares the time output from the ROM 724 with the time output from the timer 726, and 726 is a head switch Timer that measures the time from the start of magnetic head scanning, which is cleared at the falling and rising edges of the signal. 727 is the track number output from ROM 724 and output from the playback signal processing unit 110. When the track number matches, the operation is instantaneously changed to sampling operation. Otherwise, it is a sample and hold circuit that switches its operation to the hold operation. Reference numeral 707 denotes a tracking error signal output terminal for outputting the comparison result from the comparator 725.

The ROM 724 of the tracking error detection unit 20 shown in FIG. 14 stores the digital signal data reproduced in the variable speed reproduction mode, the track number of a specific track recorded and the start of scanning of the specific track. A data table is stored which shows the relationship between and the reference time until a predetermined track is detected. The timer 726 measures the time from the start of the track scan. The operation of the tracking error detection shown in FIG. 14 will be briefly described with reference to the track pattern of the quadruple speed reproduction shown in FIG. 12 as an example. The time from the start of scanning at the beginning of track No. 3 of the regular center locus 8001 until the head reaches the next track No. 4 is known in advance as described later. Is stored in the ROM 724 as a reference time. If the actual head trajectory is such as 802, the head starts to scan the next track No. 4 from the beginning of the scan of the head of track No. 3 measured by timer 726. It is evident from the figure that the actual time up to is different from the reference time. The difference between the real time and the reference time corresponds to the tracking error. In one scan of the magnetic head at the time of variable speed playback, the magnetic head 102 is attached in the track longitudinal direction from the initial value to the final value of the block number while scanning over multiple tracks. Play all the block numbers. The time required for one scan of the magnetic head is determined by the rotation speed of the rotating drum 103, and the rotation speed is 180 rpm. Since two sets of 02 are installed 180 degrees opposite each other, the time required for scanning is 16.666 msec. From such a relationship, it is understood that there is a proportional relationship between the block number of the block reproduced by the magnetic head and the time from the start of scanning of the magnetic head. Therefore, in the same way that the tracking error detector shown in FIG. 10 detects the tracking error signal from the relationship between the track number and the block number, the tracking error detector shown in FIG. The tracking error signal can be detected from the relationship between the number and the head scanning time.

In order to make the transmission rate of the reproduced digital signal at the time of variable speed reproduction the same as that at the time of normal reproduction, the rotation speed of the rotating drum 103 should be slightly higher than the reference rotation speed of 180 O rpm. It may be corrected. In this case, the time required for one scan of the magnetic head does not become the above-mentioned 16.666 msec. However, since the correction amount of the rotational speed is determined by the speed of the variable speed reproduction, it is easy to obtain the scanning time required for one scanning of the magnetic head at each speed of the variable speed reproduction. As described above, a proportional relationship between the block number and the head scanning time is established.

The configuration of the tracking error detection unit 20 shown in FIG. 14 is effective when, for example, a tracking error detection unit is configured using a one-chip microcomputer with a built-in timer counter. This is the ability to detect a tracking error without adding a new circuit or inputting a block number from the external reproduction signal processing unit 110.

Further, the tracking error detecting section 20 does not need to use digital reproduction data as shown in FIGS. 10 and 14, for example, by using the output level reproduced by the magnetic head, the variable speed of the magnetic head. It is also possible to detect a tracking deviation with respect to the reproduction track. During variable speed playback, the magnetic head scans across multiple tracks, so the output level of the signal reproduced by the magnetic head fluctuates at a fixed cycle in accordance with the head scanning Will do. At this time, the timing at which the output level of the reproduction signal is maximized is limited to some specific timings determined according to the scanning locus of the magnetic head.

For this reason, when the magnetic head scans the center of the variable-speed reproduction track, the timing at which the output level of the reproduction signal becomes maximum is stored in advance, and the reproduction signal becomes maximum during the actual scanning of the magnetic head. It is also possible to obtain the tracking deviation of the magnetic head with respect to the track for variable-speed reproduction by comparing the timing with the timing at which the change has occurred.

Further, in the above-described embodiment, the description has been given using the example of the variable speed reproduction at 4 × speed, but the present invention is not limited to this. It can be used for tracking control of a magnetic tape on which data for a variable-speed playback track at an arbitrary playback speed is recorded. It can also be used for tracking control of variable speed playback in the (reverse) direction.

Furthermore, in the above-described conventional example, the duty ratio of one control signal is modulated as a mark recording method. However, the present invention is not limited to this. For example, a plurality of continuous control signals are made the same. Marks are identified by the number of duty ratio modulations and the number of marks is used, or a pattern combining control signals with different duty ratios is used. Furthermore, for example, the "H" level interval or "L" level of control signals It is also possible to record marks by duty-modulating the section of.

Also, instead of modulating the duty ratio, there is a method of changing the recording current of the control signal in the mark portion or adding a specific signal to the control signal. Various modifications are possible without changing the gist of the present invention. It is possible.

As described above, according to the present invention, information for variable speed reproduction at an arbitrary speed higher than the normal reproduction speed is recorded in a distributed manner at positions corresponding to the scanning trajectory of the magnetic head. When performing variable-speed playback using a magnetic tape recorded with independent tracks formed on the control signal, a mark added to the control signal for identifying the variable-speed playback track is detected, and a signal for phase comparison is detected. The magnetic head can be scanned on a track for variable-speed reproduction, and the force and the block address to be reproduced can be adjusted. Since the phase comparison result is corrected by using the tracking control, tracking control capable of accurately scanning the center of the variable speed reproduction track can be realized. In addition, since the absolute speed of the tape is specified as the variable speed playback speed for the multiple tape speed recording and playback modes, the variable speed playback track (recording pattern) on the magnetic tape in all recording and playback modes is specified. ) Can be made the same, and simplification of the circuit for processing the recording signal and the reproduction signal can be realized.

Next, a third embodiment of the magnetic recording and reproducing apparatus according to the present invention will be described with reference to FIG. In the third embodiment, at the time of the variable speed reproduction, that is, the high speed reproduction mode, first, the tape speed is controlled so as to reach a predetermined speed. Next, by detecting a mark in the control signal, the rotation head is controlled so as to access the track position where the variable speed reproduction data is recorded. Then, tracking control is performed so that the scanning locus of the rotating head passes through the center of the track for variable speed reproduction. The tracking control is performed by the speed servo control of the hubstan motor, but the damping coefficient of the speed servo control can be changed according to the situation.

In FIG. 15, the components having the same reference numerals as those in FIG. 1 indicate the same functional elements, and a description thereof will be omitted.

FIG. 15 is a block diagram showing a third embodiment of the magnetic recording and reproducing apparatus according to the present invention. In the figure, 103 is a rotating drum, 102a and 102b are a pair of rotating magnetic heads mounted on the rotating drum and having opposite azimuth angles, here 102a. Has a positive azimuth angle and 102 b has a negative azimuth angle. 7 is a hub motor that drives the rotation of the hub 106, 8 is a frequency generator FG (octopus generator) that generates a frequency signal synchronized with the rotation speed of the hub motor 7, 9 is the hub motor 1 High-speed running control unit that rotates 07 at high speed and runs the tape at high speed, 10 is an adder, 11 is a motor drive circuit, 1 16 is a phase control unit that controls the rotation phase of the cap 106, 2 Numeral 0 denotes a tracking error detection unit for detecting a tracking error with respect to the variable speed reproduction track of the magnetic head, and numeral 121 denotes a switching switch.

The phase comparison unit 116 compares the phase of the mark detection signal generated by the mark detection unit 117 with the reference signal, and outputs an error signal corresponding to the phase difference to the capstan motor 7. Output to the phase controller 16 for controlling the rotation phase. That is, the phase force of the mark detection timing with respect to the reference signal is << positive when it is late, and an error signal of a level corresponding to the amount of phase delay, and conversely, the phase of the mark detection timing with respect to the reference signal is If it is advanced, it generates and outputs an error signal of negative polarity and a level according to the amount of phase advance, o

The tracking error detector 119 detects the deviation of the rotating magnetic head from the center of the desired scanning track, based on the sub information signal of the track number and block number reproduced from the reproduction signal processing circuit 110. Then, a tracking error signal having a polarity according to the direction of the shift and a level according to the shift amount is generated.

FIG. 16 shows a block diagram of one specific configuration example of the tracking error detection section 20. In the figure, 703 is a reproduction signal input terminal, 802 is a block number detection circuit, 803 is a specific track number detection circuit, 804 is a block error calculation circuit, and 805 is an error signal generation The circuit, 701 is a speed command input terminal, and 707 is a tracking error signal. The sub information signal reproduced from the reproduction signal processing unit 110 is input to the block number detection circuit 802 and the specific track number detection circuit 803. The block number detection circuit 802 detects the block number added to each block from the sub information signal, and supplies the block number to the block error calculation circuit 804. Further, the specific track number detection circuit 803 detects a specific track number from the track number added to each block from the sub information signal, and supplies it to the block error calculation circuit 804. The block error calculation circuit 804 calculates the reproduction block number at the specific track number scanned by the rotating magnetic head based on the track number and block number of the reproduced sub information signal and the speed command signal 701. Then, the deviation amount from the center of the desired scanning track is detected.

Hereinafter, this operation will be described with an example of 9 × variable speed reproduction.

In 9x playback, the rotating magnetic head 102a reproduces data across nine tracks in one scan. Therefore, for example, if one track is composed of 96 blocks from No. 0 to No. 95, data for 9x playback will be recorded in approximately 12 blocks per track. Become.

Fig. 17 shows the relationship (enlarged view) between the desired scanning of the head 102a and the block address in the specific track including the data block for variable speed playback. The double-speed variable-speed playback data is recorded at the block positions of block numbers 18 to 29 in the track of track number 2. In order to reproduce this, the scanning phase of the head 102a must be a thick solid line as shown in Fig. 8 (here, the head 102 Must be 8 0 1 as shown in

On the other hand, if the tracking of the head 102a shifts in the direction of A or B in the figure, the reproduced block number shifts up and down. In other words, in the tracking state as shown by the thin solid line in the figure, for example, the block number to be reproduced is shifted from 20 to 31, which is higher than the desired block. Conversely, it shifts in the B direction, and in the tracking state shown by the broken line in the figure, the reproduction block number is shifted from 16 to 27, which is below the desired block.

For example, if the track number is specified as 2 by the specific track number detection circuit 803, the block error calculation circuit 804 calculates the maximum value and the minimum value of the block number reproduced in this track. Based on this, the deviation of the average block number from the reference value is detected. In other words, the average block number 23.5 (the average value of the minimum value 18 and the maximum value 29) serving as the reference, whereas the average block number 25.5 (the minimum value 20 and the maximum value 3 1) and outputs +2 as the error with respect to the reference value 23.5. Conversely, in the scan of B, 21.5 (the average of the minimum value 16 and the maximum value 27) is calculated as the average block number, and 12 is output as an error with respect to the reference value 23.5.

The error signal generation circuit 805 generates a tracking error signal 707 having the characteristics shown in FIG. 18 according to the block error calculation result from the block error calculation circuit 804. In other words, if the signal is shifted in the direction A (the head scanning phase is advanced), an error signal having a positive polarity and a level corresponding to the block shift amount is output. If it is shifted to (delay), an error signal having a negative polarity and a level corresponding to the block shift amount is output as a tracking control signal. This control signal is a very detailed signal in block units. That is, in 9x speed reproduction, since 96 blocks of signals are reproduced over eight tracks, detection in units of one block corresponds to a resolution of about 0.1 (8966) when converted to a track width. . In other words, The _c- phase controller 16, which is equivalent to detecting a tracking error with an accuracy of 1 Z 10 or less of the clock width, is controlled by the system controller 118, and is controlled via the switching switch 121. The scanning phase control of the rotating magnetic head, that is, the control of the tape running speed, is performed based on the error signal from the phase comparing section 116 or the tracking error detecting section 20 which is manually operated. If the command from the control unit 118 is an open loop control command, a fixed reference voltage corresponding to the target tape speed is output to the adder 10. When the command from the control unit 118 is a closed loop control command, it operates so as to form a phase control loop based on the control signal of the switching switch 121. With this closed loop control, when the error signal of the phase comparison unit 116 or the tracking error detection unit 20 is positive, the tape speed is accelerated to relatively delay the scanning phase of the rotating magnetic head, Conversely, in the case of negative polarity, the tape speed is reduced and the scanning phase of the rotating magnetic head is relatively advanced, so that the tracking error is controlled by the phase comparator 116 and the tracking error is detected. The tracking control of the rotating magnetic head with respect to the center of the desired scanning track by the unit 20 is performed.

Next, the overall operation of the third embodiment shown in FIG. 15 will be described below.

When the user operates a command key (not shown) for variable speed playback and selects, for example, 9 × speed playback (forward), the system control unit 118 recognizes this first and switches the switching switch 121 The contact closes to the b side in the figure, the phase control unit 115 becomes open loop control, and a control signal to start the control of the high-speed traveling control unit 9 is issued.At the same time, the speed command value is also sent to the mark detection unit 117. As n = 9. Note that n indicates n times the standard speed.

As a result, with the tracking phase control system inactive, the high-speed traveling control unit 9 starts the rotation speed control of the hubstan motor 7, and the 9x-speed playback with the specified tape 104 speed is performed. It is launched at the speed of.

Next, when the tape speed reaches the predetermined 9-times speed, the control unit 118 detects this from the convergence state of the control error voltage of the speed control system included in the high-speed running control unit 9 and the like. 16 A control signal is issued again so that the operation in step 6 becomes closed-loop control. As a result, when the tape speed reaches 9x speed, the phase control system based on the control signal of the phase comparator 116 becomes closed-loop control, and the phase control operates. Led to the state.

At the moment when the phase control system goes into a closed loop, the scanning locus of the head 102a (the force that is the same for the head 102b, ') scans the recording track of the 9x-speed playback data. Not always, and may deviate from the desired scanning trajectory.

After the phase control system is closed loop, if the scanning of the head 102a is advanced in phase with respect to the desired variable speed reproduction track, the phase comparator 1 16 outputs the positive electrode by the above operation. The phase control unit 16 accelerates the capstan motor 7, that is, accelerates the tape speed, so that the error signal becomes zero, and outputs the head scanning track. Performs a number error pull-in.

Conversely, if the phase of the head 102a is delayed with respect to the desired trajectory after the closed loop of the phase control system, the negative polarity is output from the phase comparison unit 116. Is output. As a result, the tape speed is controlled to be reduced, and similarly, the pull-in control of the head scanning phase to the variable-speed reproduction track is performed.

Next, when the scanning phase of the head 102 a reaches within a predetermined range of the desired scanning phase, for example, within one track by the track pull-in control by the phase comparing section 116, the controlling section 118 controls the phase comparing section. This is detected from the convergence state of the error signal 1 16, and a control signal for switching the contact of the switching switch 1 2 1 from b to a in the figure is output again. Thereby, the subsequent control by the phase control unit 16 is switched to tracking control using the control signal of the tracking error detection unit 20.

As described above, the control signal of the tracking error detection unit 20 is an extremely fine error signal of block unit detection. With this tracking control, the head 102a scans the track on which the variable speed reproduction data is recorded. The center of the object is tracked with high accuracy.

In the third embodiment, the example is 9-times speed reproduction in the forward direction.However, the present invention is not limited to this, and the same can be applied to variable-speed reproduction in the reverse direction. Operation at an arbitrary speed is possible.

FIG. 15 shows an example in which the error detection operation by the tracking error detection unit 20 is performed on one specific track. However, the present invention is not limited to this. Perform tracking error detection You may.

FIG. 15 shows a configuration in which the phase control unit 16 is provided independently. The configuration is not limited to this configuration. For example, the phase comparison unit 116 and the tracking error detection unit 20 have this function. It is easily possible, and can be omitted.

Further, in the mark adding unit 113 in the embodiment of FIG. 15, the mark addition is performed by changing the duty ratio of one control signal. However, this is not particularly limited. The duty ratio of a plurality of control signals may be changed, or the duty ratio of a level section of one or a plurality of continuous control signals, or a duty ratio of an "L" level section may be changed. Also, a combination of control signals having different duty ratios can be used as a mark, and various modifications can be easily made without changing the gist of the present invention.

FIG. 19 is a block diagram showing an embodiment of another tracking control device according to the present invention. In the figure, reference numeral 24 denotes a damping coefficient control unit, and other units denoted by the same reference numerals as those in FIG. 10 indicate the same units, and their operations are also the same.

In the embodiment shown in FIG. 19, the damping coefficient control section 24 is controlled to weaken the damping coefficient of the speed control to reduce the maximum speed of the capstan motor only during the track pull-in control process by the phase comparison section 116. It increases the speed of the phase pull-in response and speeds up access to the variable speed playback track.

In a control system that uses both speed control and phase control, the response of the phase pull-in becomes slower as the damping coefficient of the speed control, that is, as the sensitivity ratio of the speed control system to the phase control system increases, conversely, the sensitivity ratio decreases. The smaller the coefficient, the faster the response. Therefore, it is only necessary to set a small damping coefficient to speed up the phase pull-in. However, considering the stability of the control system during normal phase control (tracking control), the damping coefficient cannot be uniquely reduced. .

In consideration of the stability of the control system, the damping coefficient is generally set to a value of about 1 or 2, and the response of the phase pull-in is naturally limited. However, the stability of the control system is not particularly required in the process of pulling the phase into the predetermined track for variable speed playback, and the damping coefficient is reduced only in this process. It is possible.

In view of this point, the embodiment of FIG. 19 does not require the stability of the control system in the phase pull-in process of the track, so that damping is weakened to speed up the access.

Although the details are omitted, the damping coefficient control unit 24 sets the damping coefficient of the speed control system to a second predetermined value during normal reproduction (including variable speed reproduction) and a first predetermined value smaller than the second predetermined value. The gain is switched by a control signal from the control unit 118, for example, by a gain switching circuit or the like so as to switch to the predetermined value.

With this configuration, as described in the embodiment of FIG. 15, when the tape speed reaches a predetermined variable speed playback speed under the control of the high-speed running control unit 9, a control signal is output from the control unit 118. You.

Upon receiving the control signal from the control unit 118, the damping coefficient control unit 24 functions to switch the gain to a first value smaller than the second value during normal reproduction. As a result, the control sensitivity of the speed control system is reduced during the operation of controlling the phase pull-in to the desired scanning track by the phase comparing section 116. In other words, the control sensitivity of the phase control system becomes relatively strong, thereby increasing the maximum speed of the capstan motor and speeding up the phase control response.

Next, when the scanning phase of the head 102 a reaches within a predetermined range of the desired scanning phase, that is, within one track described in the embodiment of FIG. 15 by the phase pull-in control by the phase comparing section 116, The control signal is output again from the control unit 1 18 to the damping coefficient control unit 24, and when the damping coefficient control unit 24 receives the control signal, the gain is again changed from the first small value to the second value during normal reproduction. Works to switch to As a result, at the time of tracking control using the tracking error detection unit 20, the damping coefficient of the speed control system is held at the second regular value corresponding to the normal reproduction, and thereafter the stability of the control system is ensured. The tracking operation is performed in the state in which the tracking operation is performed.

FIG. 19 shows a configuration in which the damping coefficient control section 24 is arranged on the speed control path. However, this is not particularly limited. For example, the damping coefficient control section 24 is arranged on the phase control system path so that the desired track phase can be adjusted. The control sensitivity of the phase control system may be relatively increased during the phase pull-in process. Switching of damping coefficient is controlled by tracking control. It is not necessary to limit the phase error to within one track, as described above, and it is not necessary to switch the phase error to a single track. Depending on the convergence of the phase pull-in, it is possible to carry out a plurality of times or in steps, and it is easy to make various modifications within the scope of the present invention.

As described above, according to the present invention, a control signal is used as a tracking control signal, and digital image data dedicated to variable-speed playback at an arbitrary speed faster than normal playback is used in accordance with the scanning locus of the rotating magnetic head. In variable-speed playback tracking control of magnetic tapes recorded independently and dispersed at track positions, a mark is added to the control signal corresponding to the recording start position of the variable-speed playback data, and this mark is used during variable-speed playback. Is detected, the phase is compared with the reference signal, and the phase is pulled into the desired scanning track. After the scanning phase of the rotating magnetic head is drawn within the predetermined range of the desired phase, The tracking error is detected based on the sub information signal of the track number and block number which are the reproduction signals of the track itself, and the tracking control is performed. . As a result, in the variable speed reproduction operation, the scanning phase of the head is accurately drawn into a desired variable speed reproduction track, and tracking which has been indispensable due to the variation in the mounting position of the control head, which is conventionally known, is essential. Compatible playback is possible without the need for correction means, and a stable and highly accurate tracking control device can be realized.

Furthermore, according to the present invention, in the process of pulling in the phase into the variable-speed playback track, the damping coefficient of the speed control is controlled to be switched to a small value. A tracking control device that can be improved can be realized.

Claims

The scope of the claims

1. A recording device that records signals on a magnetic tape using a rotating head, a standard playback mode that plays back signals at a standard tape speed, and a high-speed playback that plays back signals at a predetermined tape speed higher than the standard tape speed A magnetic recording / reproducing apparatus comprising: a reproducing apparatus having a mode;

Recording signal processing means for processing a digital signal to be recorded so that data of the digital signal reproduced in the high-speed reproduction mode is dispersedly recorded at predetermined positions on a plurality of predetermined tracks; Is recorded such that the data for high-speed reproduction is arranged at a position along a scanning trajectory of the rotating head on the magnetic tape;

Mark adding means for generating a mark corresponding to the position of the track on which the digital signal data reproduced in the high-speed reproduction mode is recorded and adding the mark to the control signal;

When recording the signal by the recording device, a control signal to which the mark signal is added corresponding to each track position is recorded on the magnetic tape, and when the signal is reproduced by the reproducing device, the mark is recorded. Control head that plays back the control signal with

Mark detecting means for detecting the mark from the reproduced control signal; phase comparing means for detecting a phase difference between the mark and a reference signal synchronized with the rotation of the rotary head;

And a capstan means for controlling a running speed of the magnetic tape so that the phase difference becomes a predetermined reference value.

2. The magnetic recording / reproducing apparatus according to claim 1, wherein the mark adding means changes a duty ratio of one or a plurality of continuous control signals to generate the mark, or The mark is generated by pulse width modulation of one of a high level section and a low level section of one or a plurality of continuous control signals.

3. The magnetic recording and reproducing apparatus according to claim 1, further comprising: the high-speed reproducing mode. Means for detecting a tracking error indicating a deviation between a track on which digital tongue signal data reproduced in the high-speed reproduction mode is recorded and an actual scanning trajectory of the rotary head, and eliminating the tracking error. A force for changing the phase of the mark or the reference signal detected by the phase comparing means, or a phase adjusting means for changing the phase difference.

4. The magnetic recording / reproducing apparatus according to claim 3, wherein the mark adding means changes a duty ratio of one or a plurality of continuous control signals to generate the mark, or The mark is generated by pulse width modulation of one of a high level section and a low level section of one or a plurality of continuous control signals.

5. The magnetic recording / reproducing apparatus according to claim 3, wherein each of the tracks is composed of a plurality of data blocks, and the digital signal is recorded in a distributed manner over the plurality of data blocks. In the data block, a main information signal and a sub information signal including identification information indicating a track number and a data block number are recorded.

The tracking error detecting means indicates a track number of a specific track on which digital signal data reproduced in the high-speed reproduction mode is recorded and a reference data block number to be detected when scanning the specific track. Storage means for storing the data table,

The tracking error detecting means includes: a data in the sub information signal reproduced when the rotating head actually scans one or more specific tracks corresponding to the mark in the high-speed reproduction mode. A difference between a block number and a reference data block number indicated in the data table is detected, and the tracking error signal corresponding to the difference is generated.

6. The magnetic recording / reproducing apparatus according to claim 3, wherein each of the tracks is composed of a plurality of data blocks, and the digital signal is recorded in a distributed manner over the plurality of data blocks. Records a main information signal and a sub information signal including identification information indicating a track number and a data block number. The tracking error detecting means is configured to determine a relationship between a track number of a specific track on which digital signal data reproduced in the high-speed reproduction mode is recorded and a reference time from the start of scanning of the specific track to detection of a predetermined track. Storage means for storing a data table indicating the following, and a timer for measuring the time from the start of scanning of the track,

In the high-speed playback mode, the tracking error detection means performs the actual operation from the time when the rotating head actually starts scanning one or more specific tracks corresponding to the marks to the time when a predetermined track is detected. A time is detected using the timer, a difference between the reference time indicated in the data table and the detected real time is detected, and the tracking error signal corresponding to the difference is generated.

7. The magnetic recording / reproducing apparatus according to claim 3, wherein the phase adjustment unit is configured to determine a phase of the mark in a direction in which the difference becomes zero in accordance with the tracking error signal generated by the tracking error detection unit. Either adjust the phase of the reference signal or the phase of the reference signal, or make a change to the value of the phase difference from the phase difference detecting means.

8. The magnetic recording and reproducing apparatus according to claim 1 further includes:

High-speed running control means for running the magnetic tape at the predetermined speed higher than the standard speed in the high-speed playback mode;

Means for detecting a tracking error indicating a deviation between a track on which the digital signal data reproduced in the high-speed reproduction mode is recorded and an actual scanning locus of the rotating head during the high-speed reproduction mode. ,

Switching means for selectively outputting one of the phase difference from the phase comparison means and the tracking error from the tracking error detection means in accordance with a control signal;

In the high-speed playback mode, when the magnetic tape reaches the predetermined speed, the switching means selects the phase difference from the phase comparison means, and when the phase difference reaches a predetermined range, the switching means Has control means for generating the control signal so as to select the tracking error from the tracking error detection means,

The capstan servo means, according to an output from the switching means, The running speed of the magnetic tape is controlled so that the phase difference becomes a predetermined reference value or the tracking error becomes zero.

9. The magnetic recording and reproducing apparatus according to claim 8, wherein the mark adding means generates the mark by changing a duty ratio of one or a plurality of continuous control signals, or Alternatively, the mark is generated by pulse width modulation of one of a high level section and a low level section of a plurality of continuous control signals.

10. The magnetic recording / reproducing apparatus according to claim 8, further comprising: means for adjusting a control damping coefficient when the capstan servo means controls a traveling speed of the magnetic tape in the high-speed reproducing mode. The damping coefficient adjustment unit uses a first damping coefficient until the phase difference from the phase comparison unit reaches a predetermined value, and the phase difference from the phase comparison unit has reached a predetermined value. Thereafter, a second damping coefficient larger than the first damping coefficient is used.

11. The magnetic recording / reproducing apparatus according to claim 10, wherein the mark adding means generates the mark by changing a duty ratio of one or a plurality of continuous control signals, or The mark is generated by pulse width modulation of one of a high level section and a low level section of one or a plurality of continuous control signals.