JPH0546954A - Magnetic recording and reproducing apparatus - Google Patents

Abstract

PURPOSE:To reduce the displacement amount of an actuator and to perform a special reproducing operation by using a frame as a unit by a method wherein the title apparatus is provided with the following: an actuator control means; a write means using a field as a unit; and readout means. CONSTITUTION:Reproduction signals from magnetic heads are FM-demodulated and introduced from terminals 101, 102. An output from an A/D converter 103 is supplied to memories 105 to 108; a write address and a readout address are given respectively from control circuits 109, 110. An output from an A/D converter 104 is supplied to memories 111 to 114; a write address and a readout address are given from control circuits 115, 116. An output from a selector 117 is used as an analog luminance signal via a dropout compensation circuit 119 and a D/A converter 121. An output from a selector 118 is passed through a dropout compensation circuit 120. A color signal is separated into PB and PR in a line sequential manner; it is converted into an analog signal via D/A converters 124, 125. A multiplied speed is designated to a system control part 130 form an operating part; the control part 30 indicates a W/R period to a control circuit, and a selector is changed over. Three element pieces are reproduced and stored, and one frame portion is read out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus equipped with signal processing means effective for special reproduction.

[0002]

2. Description of the Related Art In a magnetic recording / reproducing apparatus such as a video tape recorder (hereinafter referred to as VTR), a dynamic tracking system is adopted when performing special reproduction (normal forward double speed reproduction, reverse forward double speed reproduction, still reproduction, etc.). There is. FIG. 5 shows an example of a conventional dynamic tracking system.

Actuators 12 and 13 are provided around the rotary drum 11 so as to face each other by 180 °, for example. Magnetic heads 14 and 15 are attached to the tips of the actuators 12 and 13, respectively. The signals reproduced from the magnetic heads 12 and 13 are input to the envelope detectors 16 and 17, respectively, and are envelope-detected. The detected outputs are respectively the A / D converter 1
System controller 20 which is input to 8 and 19 and digitized
Entered in. The envelope detection output indicates the tracking status, and the system control unit 20 generates an actuator control signal according to the tracking deviation. That is, the system control unit 20 controls each actuator 1
The control data for 2 and 13 are output, and the D / A converter 2
1 and 22 are supplied. The control signals from the D / A converters 21 and 22 are supplied to the drive circuits 23 and 24, become drive voltages, and are supplied to the corresponding actuators 13 and 14.

As the actuators 13 and 14, bimorph plates having piezoelectric elements bonded to each other are used. The bimorph plates are displaced according to the applied voltage and the magnetic head at the tip end is moved in the axial direction of the rotary drum (direction orthogonal to the track). Tracking can be corrected by moving the position. In the case of special reproduction, since the displacement pattern of the actuator is known in advance, control data corresponding to the special reproduction is read from the memory of the system control unit 20 and controlled. In this control, tracking deviation (expansion and contraction of the tape, and possibly caused by the difference between the recording model and the reproducing model) is detected by envelope detection, and the correction data is detected by the system controller 20.
And the control data is corrected.

With the above-described dynamic tracking system, even in a tape running state where the magnetic head straddles a plurality of tracks such as special reproduction, the magnetic head can trace well corresponding to the tracks. ..

In this dynamic tracking system, there are a field reproduction mode and a frame reproduction mode. The field reproduction mode controls the magnetic head position on a field-by-field basis, and the displacement of the actuator may be such that a track for a field is traced. In the frame reproduction mode, the magnetic head position is controlled in units of frames, and it is necessary to reproduce a signal track for one frame and capture a signal.
The displacement of the actuator has to be largely controlled. In particular, when the recording method is a multi-channel recording method or a segment recording method in which a signal for one field is divided into a plurality of tracks and recorded, the necessary displacement amount of the actuator becomes large, and it becomes difficult to realize this. There is a problem. Further, even if it is realized, there is a problem that the actuator cannot be returned to its original state while being displaced, or the actuator is deteriorated quickly.

[0007]

As described above, according to the conventional dynamic tracking system, the required displacement amount of the actuator becomes large when performing special reproduction in frame units, which makes it difficult to realize this. There is a problem. Further, even if it is realized, there is a problem that the actuator cannot be returned to its original state while being displaced, or the actuator is deteriorated quickly. Therefore, it is an object of the present invention to provide a magnetic recording / reproducing apparatus capable of performing special reproduction in frame units by reducing the displacement amount of an actuator.

[0008]

SUMMARY OF THE INVENTION The present invention comprises a rotary drum, a plurality of actuators mounted on the rotary drum,
Magnetic heads fixed to the tip of each actuator, actuator driving means for controlling the displacement of each actuator to obtain tracking, and signal processing for supplying a signal to the magnetic head or processing an output signal of the magnetic head. Means and tape drive means for running a magnetic tape attached to the periphery of the rotary drum, and a video signal for one field is distributed and recorded on a plurality of tracks, and the magnetic recording / reproduction is performed. In the device,

When the magnetic tape attached around the rotary drum is run by the tape driving means to perform special reproduction, the actuator is driven through the actuator driving means so that the magnetic head reads in field units. Controlling means, a reproduction signal reproduced from the magnetic head in a field memory group on a field-by-field basis, and a signal read from the field memory group by reading out the same signal as a frame-by-frame signal. With.

[0010]

With the above means, even if the displacement amount of the actuator is such that only the signal in the field unit is read, the reproduction output from the memory group can be converted into the signal in the frame unit.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example in which the present invention is applied to a VTR (UNIHI standard) currently developed for commercial use. This type of VTR is realized by a so-called segment recording method in which an image signal of one field is distributed and recorded in a plurality of tracks in order to record a wideband image signal such as a high definition television signal.

Now, the UNIHI standard will be described. FIG. 4A shows an example of a recording pattern recorded by the segment recording method, and an arrow T indicates the head traveling direction.
The arrow H indicates the head scanning direction. In this method, an image signal for one field is composed of three segments, and an image signal for one frame is created by two fields.

FIG. 1B shows a magnetic head mounted on the rotary drum 1. In the figure, 14 magnetic heads are mounted (A1, A2, A1 ', A2', A1
″ ”, A2 ″, B1, B2, B1 ′, B2 ′, B1 ′
, B2 ″, e11, e21), but basically, it may be considered that the two magnetic heads face each other by 180 °. The segment recording is realized in this device as follows.

First, while the rotary drum 1 rotates 1/2 turn,
One recording head group (A1, B1) scan-records the first segment (S1) (indicated as one track in the drawing, but actually has two tracks of A channel and B channel). The other recording head group (A2, B2) scans and records the second segment (S2) by ½ rotation of the above, and the head group (A1, B2
1) scan-records the third segment (S3). This completes the image signal recording of the first (odd) field.

Similarly, recording of the fourth, fifth, and sixth segments (S4, S5, S6) is performed, and the image signal recording of the second (even) field is completed. Therefore, when the rotary drum 1 rotates three times, six segments (S1 to S6)
(Image signal for one frame) will be recorded.
At the time of reproduction, each segment is scanned in the same procedure as at the time of recording, but consider the case of special reproduction such as slow reproduction.

In the case of special reproduction, the traveling speed of the magnetic tape is different from the recording speed. That is, in the case of special reproduction, the running locus of the rotary magnetic head on the tape is inclined with respect to the recording track as shown in FIG. In FIG. 6C, +1 means the tape running speed at the time of recording, 0 means the tape is stopped (still reproduction), and -1 means reverse reproduction. Therefore, in special reproduction, in order to obtain a reproduced signal without noise, it is necessary to displace the magnetic head in the width direction of the track (segment) according to the tape running speed. The method for realizing this displacement is the dynamic tracking method.

In the dynamic tracking method, an actuator that corrects the scanning locus of the magnetic head is used. Although various actuators can be considered, here, a bimorph plate in which two flat plate-shaped piezoelectric elements are stacked is considered. In FIG. 4, the reproducing head group (A1
″, B1 ″, A2 ″, B2 ″) are fixed to the bimorph board.

Returning to FIG. 1, description will be made. At the input terminal 101, the signal reproduced from the A-channel magnetic head is F
A signal reproduced from a B channel magnetic head is FM-demodulated and introduced into the input terminal 102. The signal at each input terminal is the A / D converter 103,
It is digitized at 104. The digitized signals are respectively supplied to the field memory group and subjected to so-called deshuffling. The output of the A / D converter 103 is supplied to the memories 105, 106, 107 and 108. The write address of these memories 105 to 108 is given from the write control circuit 109, and the read address is given from the read control circuit 110.
The output of the A / D converter 104 is the field memory 11
1, 112, 113, 114. The write addresses of these field memories 111 to 114 are given from the write control circuit 115, and the read addresses are given from the read control circuit 116.

The outputs from the memories 105 to 108 are supplied to the selectors 117 and 118, and the memories 111 to 118.
The output from 114 is also supplied to selectors 117 and 118. The selector 117 selectively derives a luminance signal component from the signal read from the memory, and the selector 118
Selects and derives a color signal component from the signals read from the memory.

The luminance signal output from the selector 117 is dropout-compensated by the dropout compensation circuit 119, supplied to the D / A converter 121, and output to the output terminal 122 as an analog luminance signal.

The color signal output from the selector 118 is
The dropout is compensated in the dropout compensation circuit 120 and input to the vertical filter 123. In the vertical filter 123, the color signals are line-sequential PB, PR.
The PB and PR signals are separated into analog signals by D / A converters 124 and 125, respectively, and led to output terminals 126 and 127.

Here, the reproduced signals of the A channel and the B channel are TCI (time compressed integration) signals. The TCI signal is subjected to TCI decoding and deshuffling in the memory and selector section. The signal output from the selector 118 is a line-sequential color signal.

Now, FIG. 2 is a timing chart when signal processing is performed at +1/2 speed. in this case,
The video signals reproduced in the order of the reproduction segments shown in FIG. 7B are shown in FIGS. 7D, 7E, 7F, and 7G.
Signals are written to the respective field memories 105, 106, 107 and 108 at the field timings shown in FIG. WR is a writing period. When the same field is reproduced subsequently, overwrite is performed on the memory of the same number. When a different field is reproduced, the number is updated and the next corresponding memory is written. O / E in FIG. 7A is an odd / even field identification signal of the VTR output, and FIG. 7C is an odd / even field identification signal of the TCI signal written in the memory.

In the period T1, segments 1 to 3 are reproduced, and the reproduction signal is written in the memory 105 twice by overwriting. In the period T2, the segments 4 to 6 are reproduced, and the reproduced signal is overwritten twice in the memory 106. During the period T3, segments 1 to 3 are reproduced, and the reproduced signal is overwritten in the memory 107 by 2 times.
Written twice. In the period T4, the segments 4 to 6 are reproduced, and the reproduction signal is overwritten twice in the memory 107. On the other hand, looking at the reading, in the period T1, the data of the memory 107 and the data of the memory 108 are read.
Data is read. That is, the data for one frame is read. Also in the period T2, the data of the memory 107 and the data of the memory 108, that is, the data for one frame are read. Further, in the period T3, the data of the memory 105 and the data of the memory 106, that is, the data for one frame are read. Also in the period T4, the memory 104
Data of the memory 105 and the data of the memory 105, that is, the data for one frame is read. This reading was performed in units of fields when writing, but it means that reading was performed twice (1/2 speed) in units of frames when reading.

The write / read timing is determined by the system controller 130 from the write control circuits 109 and 11.
0, which is realized by being applied to the read control circuits 110 and 116. The system control unit 130 is adapted to be given a double speed designation signal from the operation unit. In addition, the system controller 130 outputs selectors 117 and 118.
A switching signal is also applied to. In the above description, the write / read operation of the memory group (A channel side) on one side of the pair of magnetic head outputs (A channel, B channel) has been described. Done,
Deshuffling is obtained.

According to the above system, in the case of special reproduction, three segments are reproduced by the magnetic head and written into the field memory group, and one frame is read out.

FIG. 3 shows a displacement pattern of an actuator having a head for scanning each segment.
The pattern at the time of +0.5 times is shown. In the figure, the solid line shows the part scanning each segment, and the broken line shows the part returning toward the next scanning segment. The head groups h1 and h2 shown close to the broken line indicate the returning head group, and S1, S2, ... Shown close to the solid line indicate the scan segment. Since each segment is alternately scanned by the head groups h1 and h2, the displacement pattern of h1 and h2 is clear from the figure. Tracking the segment movement of one head group (channels A and B) results in a thick line, and in the field unit, the displacement is 3 segments at the maximum. Although the actuator is actually driven in field units, the signals output from the memory group are in frame units.

[0029]

As described above, according to the present invention,
Special displacement can be performed in frame units by reducing the displacement of the actuator.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing an embodiment of the present invention.

2 is a timing chart for explaining an operation example of the apparatus of FIG.

3 is a diagram showing an example of a displacement pattern of an actuator in the device of FIG.

FIG. 4 is an explanatory diagram of a recording pattern, a head device, and a tracking pattern shown for explaining the segment recording method.

FIG. 5 is an explanatory diagram of a configuration of a conventional tracking servo system.

[Explanation of symbols]

103, 104 ... A / D converter, 105-108, 11
1-114 ... Field memory, 109, 115 ... Write control circuit, 110, 116 ... Read control circuit, 1
17, 118 ... Selector, 119, 120 ... Dropout compensation circuit, 121, 124, 125 ... D / A converter, 123 ... Vertical filter, 130 ... System control circuit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H04N 5/93 C 4227-5C

Claims (1)

[Claims] 1. A rotary drum, a plurality of actuators mounted on the rotary drum, a magnetic head fixed to the tip of each actuator, and actuator driving means for controlling the displacement amount of each actuator to obtain tracking. A signal processing means for supplying a signal to the magnetic head or for processing an output signal of the magnetic head, and a tape driving means for running a magnetic tape attached to the periphery of the rotary drum. In a magnetic recording / reproducing apparatus for distributing and recording a video signal on a plurality of tracks and reproducing the same, special reproduction is performed by running the magnetic tape attached around the rotary drum by the tape driving means. In this case, the actuator driving means is used so that the magnetic head reads in a field unit. Means for controlling the actuator; means for writing a reproduction signal reproduced from the magnetic head in a field memory group in field units; and a signal in a frame unit by reading the same signal when reading a signal from the field memory group. A magnetic recording / reproducing apparatus comprising: a reading unit.