JPH0832001B2 - Slow playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is applied to improve reproduction image quality in, for example, a video tape recorder (hereinafter referred to as VTR), and is provided on a rotary drum. The present invention relates to a slow reproducing device in which the head can be displaced in the width direction of the magnetic tape, and the head locus during slow reproduction is traced faithfully to the locus during recording.

[Prior Art] FIG. 10 is a vertical cross-sectional view of a rotary drum in a conventional slow speed reproduction device. In FIG. 10, (1) is a rotary shaft,
(2) is a fixed lower drum, (3) is a rotating upper drum,
(4) is a head mounted on the upper drum (3) so as to be detachably attached, (5) is a head fixed to the tip of the head (4), and (6) is attached to the lower drum (2). On the other hand, a bearing that supports the rotating shaft (1) in a freely rotatable manner,
(7) is an upper transformer that rotates together with the upper drum (3), (8) is a fixed lower transformer, (9) is a pedestal supported by the rotating shaft (1) and carrying the upper drum (3), (13) is a magnetic tape.

The configuration of each of the above units will be described in more detail as follows.

The head (5) is fixed and held at a fixed position with respect to the upper drum (3), and the tip of the head (5) slightly protrudes from the outer periphery of the upper drum (3) and the connecting portion (10) wiring board (1
1) It is electrically connected to the upper transformer (7) via the connection section (12). The upper drum (3) is rotated at a constant high speed, and the magnetic tape (13) is wound slightly obliquely around the outer peripheral surfaces of the upper drum (3) and the lower drum (2) and runs at a predetermined speed. . The head (5) contacts the magnetic tape (13) to magnetically record or reproduce a video signal or an audio signal.

The upper transformer (7) is attached to the pedestal (9) and rotates together with the pedestal (9). The lower transformer (8) faces the upper transformer (7) at a small interval, whereby the upper and lower transformers (7) and (8) are magnetically coupled and transmit signals to each other. The lower transformer (8) is connected to a control circuit (not shown) provided outside.

Moreover, in FIG. 10, (75) is a magnet attached to the upper drum (3), and (18) is a rotational position for detecting the magnetic line of the magnet (75) to detect the rotational position of the upper drum (3). It is a detector.

 Next, the operation of the above configuration will be described.

The head (5) diagonally crosses the magnetic tape (13) by the running of the magnetic tape (13) and the rotation of the head (5). These transverse lines are parallel to each other, as shown in FIG. In FIG. 11, (13a) is the trajectory of the magnetic tape (13), (V1) is the normal feeding speed of the magnetic tape (13),
(5A) is the trajectory of the head (5), (V0) is the rotation speed of the head (5), and the trajectory (13a) of the magnetic tape (13) and the trajectory (5A) of the head (5) are as shown in the figure. Intersects with.

Therefore, the relative locus drawn on the magnetic tape (13) by the head (5), that is, the above-mentioned transverse cutting line becomes (A) as shown in FIG. 11 (a), and the interval (P) is the track pitch. By the way, the feed speed (V1) at the time of still reproduction is 0, and the crossing line (Ao) is the head (5).
Matches the trajectory (5A) of. The relative locus of the head (5) with respect to the magnetic tape (13) at the time of slow reproduction in which the feeding speed of the magnetic tape (13) decreases from (V1) to (V1 / 4) is shown in FIG. 11 (b). Like (As). In this way, when the magnetic tape (13) is reproduced at a speed different from the normal speed (V1), for example, in the case of still reproduction, slow reproduction, high-speed search reproduction, the head (5) is the recording locus. If it is not accurately tracked, it will be displaced, and the signal level at which the head (5) picks up will be low, and it will be difficult to obtain a clear reproduced image and reproduced sound.
It causes noise and blurring.

As one of the solutions to such a problem, conventionally,
As disclosed in Japanese Examined Patent Publication No. 58-40874, there has been proposed one capable of performing slow reproduction in which the feeding speed of the magnetic tape is reduced to 1/2 of the normal speed in a state with less noise and blurring. This is 1 / the normal tape feed rate
Although noise and blurring can be suppressed only during slow playback corresponding to 2, the above problems cannot be solved during slow playback at a speed lower than that.

Further, in order to solve the problem at the time of slow reproduction at 1/2 speed or less, as described in JP-A-57-17081, a capstan motor for driving a magnetic tape is intermittently driven. It has been known that a truck is configured to move one pitch in one field.

[Problems to be Solved by the Invention] In the conventional slow playback device configured as described above, the operation is repeated when the track is moved by one pitch during one field and then stopped. There was a problem that the time axis of the horizontal synchronizing signal of the reproduced signal fluctuated by 0.6% or more due to the uneven rotation of the capstan motor, causing the screen to vibrate.

The present invention has been made in order to solve the above-mentioned problems, and can stably perform tape running even at an arbitrary speed of 1/2 or less of a normal tape feeding speed to obtain a high quality image with less blur and noise on the screen. It is an object of the present invention to provide a slow playback device that can obtain various playback images.

[Means for Solving Problems] A slow reproducing device according to the present invention includes a pair of rotary heads for reproducing a video signal recorded on a magnetic tape, an elastic member for supporting the rotary heads, and an elastic member. The rotary head in cooperation with the magnet device by giving a signal according to the speed of the coil magnetic tape. A rotating drum adapted to be displaced in the width direction of the magnetic tape, a rotary pulse generator for outputting a pulse train proportional to the rotation speed of a capstan motor for driving the magnetic tape, and a pulse edge of the pulse train No voltage is applied to the capstan motor for a predetermined time from a predetermined pulse edge, and the capstan motor is not applied until the next pulse edge after the predetermined time. It is characterized in that a control device for applying a voltage to the motor is provided, and the capstan motor is intermittently driven.

[Operation] According to the present invention, the head is magnetically displaced in the width direction of the tape in cooperation with the coil by supplying a control current from the outside to the drive section, whereby the head locus during reproduction is obtained. It is possible to match the recording track.
Further, by driving the capstan motor with a plurality of pulse trains per field and alternately repeating slow reproduction and still reproduction, the low speed rotation of the capstan motor is proportional to the speed difference as uniform and stable rotation. The time-axis fluctuation of the reproduction horizontal synchronizing signal can be halved compared to the conventional one, and slow reproduction with less screen noise and blurring can be performed.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing a main part of a rotary drum which is a constituent element of a slow speed reproducing device according to an embodiment of the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a vertical section showing the main part in more detail. FIG. 4 is a bottom view of FIG. 3, and in each of these drawings, (1) to (3) and (5) to (13) have the same structure as the conventional device shown in FIG. Therefore, the same reference numerals are given.

In FIGS. 1 and 2, (4a) is a drive unit for carrying the head (5) and displacing the head (5) in the width direction of the tape, and (14) is a drive current for the drive unit (4a). A non-rotating contactor for supplying, (15) a rotating electrode provided on a part of the pedestal (9) so as to make sliding contact with the contactor (14),
Reference numeral (16) is a connection portion for electrically connecting the electrode (15) to the drive portion (4a) via the wiring board (11).

In the main part shown in FIGS. 3 and 4, (41) is a non-magnetic leaf spring having a head (5) attached to the tip, (42)
Is a cylindrical coil mounted on a leaf spring (41), (43)
Is a cylindrical permanent magnet that causes a magnetic reaction to move the cylindrical coil (42) up and down, and (44) is a strong magnet mounted on the upper drum (3) that carries the cylindrical permanent magnet (43). The magnetic yoke (45) is a ferromagnetic plate attached to the yoke (44) to form a magnetic closed circuit together with the cylindrical permanent magnet (43). The ferromagnetic plate (45) extends in a direction away from the head (5) and has an attachment portion (45a) formed on the extension thereof. (46) is a screw for attaching the leaf spring (41) to the attachment portion (45a), (47) is a spacer, (48) is a washer, (49) is a screw for attaching the yoke (44) to the upper drum (3), (50) is a recess formed in the upper drum (3) for accommodating the drive section (4a).

The free end of the leaf spring (41) is movable up and down, and the cylindrical coil (42) carried by the leaf spring (41) includes a cylindrical permanent magnet (43) and a ferromagnetic plate (45). It is arranged in an annular gap formed between and can be displaced up and down,
An appropriate magnetic flux is generated in the coil (42) by passing a control current through the cylindrical coil (42), and the coil (42) is vertically displaced by the interaction with the permanent magnet (43). The leaf spring (41) is deformed along with the vertical displacement of the coil (42) so that the head (5) can be displaced in the width direction of the tape.

A round hole (52) for centering is formed substantially in the center of the leaf spring (41), and a cylindrical jig (53) is inserted into the round hole (52) to align with a cylindrical permanent magnet (43). As a result, the cylindrical coil (42) can be centered and positioned on the annular gear formed between the cylindrical permanent magnet (43) and the ferromagnetic plate (45). By tightening the screw (46) in this state, the drive unit (4a) is assembled as a unit.

The drive unit (4) thus assembled as a unit
a) is installed in the recess (50) of the upper drum (3) with screws (49). At this time, the amount and posture of the head (5) protruding from the outer peripheral surface of the upper drum (3) must be adjusted correctly. For this purpose, three head position adjusting holes (51a), (51b) and (51c) are provided in the upper drum (3). The four points including these three holes (51a), (51b), (51c) and the head (5) are arranged in a cross shape. A drive unit mounting hole (49a) is formed radially inward from the intersection of the cross-shaped arrangement by a distance (l), and the yoke (44) is screwed through the hole (49a) into the upper drum (3). ) Is attached to the specified condition. After that, position adjusting wedges are inserted into the head position adjusting holes (51a) to (51c) to generate a rotational force at the holes (51a) and (51b) to adjust the posture, and at the hole (51c), the head ( Adjust the protrusion amount of 5). Thereby, the position of the driving section (4a) with respect to the upper drum (3) becomes accurate. If necessary, further tighten the screw (49) in this state.

As described above, between the permanent magnet (43) and the ferromagnetic plate (45) in the high magnetic flux magnetic closed circuit composed of the permanent magnet (43), the yoke (44), and the ferromagnetic plate (45). The cylindrical coil (42) located in the annular gear of (4) can apply a magnetic force to the permanent magnet (43) by its control current to displace the leaf spring (41). )
In order to prevent the magnetic flux leaking toward, the mounting portion (45a), which is an extension of the ferromagnetic plate (45), is arranged farther from the head (5).

 Next, the operation of the above configuration will be described.

For example, if the tape feed speed (VS) is the normal feed speed (V
Magnetic head (5) for 1/4 of slow playback
When the head is moved from the fixed position in the direction of the arrow (T) in FIG. 11C, that is, in the width direction of the tape to change the trajectory of the head (5) from (5A) to (5B), the tape (13) The relative locus between the head and the head (5) coincides with the relative locus (A) at the time of recording. Even if the tape feed speed is other than the above-mentioned tape feed speed, by moving the head by about P (1-VS / V1) during one field in correspondence with the tape feed speed, the relative locus (as in the above) ( It can be matched to A). This also applies to reverse slow playback.

FIG. 5 is a control circuit diagram for controlling the rotary head in the rotary drum having the above-mentioned configuration. In FIG. 5, the head is divided into two systems (5a) and (5b), and accordingly, all the constituent elements of each part (a ) And (b) are assigned subordinate symbols.

In FIG. 5, (61a) and (61b) are periodic signal generators controlled by a switching signal. The switching signal is detected by the magnet (75) attached to the movable part (74) and the position detection head (76) to detect the mechanical position of the movable part (74), and the switching signal generator (77) is detected accordingly. Created by.

In addition, the periodic signal corresponds to the tape speed and
Since it is a signal for moving about P (1-VS / V1) between fields, the slope of the periodic signal changes according to the tape speed.

The outputs of the periodic signal generators (61a) and (61b) are operational amplifiers (64a) and (64b), differential amplifiers (69a) and (69b),
Current limiters (65a), (65b), resistors (62a), (63a),
(68a), (70a), (62b), (63b), (68b), (70
b) and the capacitors (71a) and (71b) are supplied to the drive circuit. The output of this drive circuit, that is, the control current, is passed through the contactors (14-1), (14-3), electrodes (15-1), (15-3) on the individual control side to the coils (42a), ( 42
supplied to b). The non-control side terminals of the individual coils (42a) and (42b) are made common, and a reference potential is provided via a pair of common side electrodes (15-2) and common side contacts (14-2). It is connected to the. The control current is controlled by the individual coils (42
The magnetic field generated by being supplied to a) and (42b) causes a magnetic reaction with the cylindrical permanent magnet (43), causing mechanical displacement in the individual heads (5a) and (5b). Let
The displacement amount is controlled so that the head locus during reproduction matches the recording locus on the magnetic tape. Further, the control current is supplied to the coils (42a) and (42b) even when the heads (5a) and (5b) are not in contact with the magnetic tape. The signals reproduced by the individual heads (5a) and (5b) are transferred from the movable section (74) to the head amplifier by electromagnetic conversion between the upper transformers (7a) and (7b) and the lower transformers (8a) and (8b). (72
a) and (72b), the output of which is output as a reproduction signal via a signal processor (78) via a switch (73) which is switched by a switching signal.

The current limiters (65a) and (65b) are window comparators (66a) and (66b) and current limiting means (67), respectively.
It consists of a) and (67b).

Also, the resistors (63a), (63b), (70a), (70
b), capacitors (71a), (71b), coils (42a),
(42b) is the resistance value of resistors (63a) and (63b)> resistance (70
The resistance values of a) and (70b), the impedances of the capacitors (71a) and (71b)> the resistance values of the coils (42a) and (42b) are set to have a relation.

Next, the operation of the rotary drum control circuit will be described.

The drive circuit has resistors (68a), (6
8b) voltage across the coil, that is, the current flowing through the coils (42a) and (42b) is detected by the differential amplifiers (69a) and (69b), and a loop that performs current feedback operation, and capacitors (71a) and (7b).
It has two feedback loops, a loop for performing voltage feedback operation via 1b).

When the frequency is high, the impedance of the capacitors (71a) and (71b) approaches zero. Therefore, the voltage feedback operation becomes dominant over the current feedback operation, and the voltage drive operation is performed. On the other hand, when the frequency is low, the capacitor (71a),
The impedance of (71b) approaches ∽. Therefore,
The current feedback operation becomes dominant over the voltage feedback operation, and the current feedback operation is performed. Here, the relationship between the drive fundamental frequency of the heads (5a) and (5b) cooperating with the coils (42a) and (42b) and the mechanical resonance frequency of the movable part (74) is: drive fundamental frequency <machine of drive part The counter electromotive force is generated at both ends of the coils (42a) and (42b) at the time of voltage driving, where the output impedance is small by performing current driving near the driving fundamental frequency and voltage driving near the resonance frequency. Is absorbed and short-circuit braking is performed.

The following circuit constants are selected in order to eliminate the difference in gain between the current driving operation and the voltage driving operation.

The current limiter (65) including the window comparators (66a) and (66b) and the current limiting means (67a) and (67b).
a) and (65b) are resistors (68a) and (68) inserted on the control side.
The voltage across both ends of b), that is, the current flowing through the coil, is detected and the displacement of the heads (5a) and (5b) is calculated as follows: | desired speed −1 | × track pitch <head displacement limit <
It is configured to limit the control current so that it is a structural displacement limitation of the head. That is, the voltage across the resistors (68a) and (68b) is used to control the current controllers (65a) and (65b) and the current feedback differential amplifier (69).
a) and (69b) are working together.

FIG. 6 shows an outline of the slow playback device, in which (700) is the control circuit of FIG. 5, and (800) is the upper drum (3) and the lower drum (2) shown in FIG. The rotating drum, (80) is a capstan, (82) is a pinch roller, and the capstan (80) and the pinch roller (82) press the magnetic tape (13) to drive it. (8
1) is a capstan motor, which has a drive control circuit, which will be described later, built therein, and performs torque control in proportion to the voltage applied to the terminal (83). (84) is a rotary pulse generator, which is attached to the capstan motor (81) and has a terminal (8
Output pulse to 5).

FIG. 7 shows a control circuit for low speed rotation of the capstan motor (81), which realizes variable speed slow reproduction, and is a pulse output from the rotation pulse generator (84). Generates a drive wave.

Hereinafter, a specific configuration of the control circuit shown in FIG. 7 will be described together with its operation.

In FIG. 7, the rotation pulse from the output terminal (85) of the rotation pulse generator (84) connected to the capstan motor (81) is transferred to the mono-multivibrator (101), (10).
Enter in 4). The number of rotation pulses is proportional to the number of rotations of the capstan motor (81).

Now, the capstan motor (81) is set to rotate once per second,
When n rotation pulses are output per rotation, 1 second
Since it corresponds to 60 fields, a rotation pulse having a waveform as shown in FIG. 9A is output at n / 60 fields per field.

The one mono-multivibrator (101) is a device which outputs a pulse of a predetermined width at the rising edge which is the edge of the rotation pulse of the input signal, and the width of the pulse is connected to the mono-multivibrator (101). The time constant of the mono-multi adjuster (102) and the condenser (103) can be set. The other mono multivibrator (10
4) is a device that outputs a pulse of a predetermined width at the falling edge which is the edge of the rotation pulse of the input signal, and the width of the pulse is a mono-multi-adjustment volume (105) connected to this mono-multivibrator (104). And the time constant of the capacitor (106).

The above two mono-multi vibrators (101), (104)
If the pulses output from are adjusted to the same width, the two output pulses will pass through the NOR gate (107),
AND gate (108) opened and closed by the output of the counter (121)
Is input to When the output of the counter (121) is "L", the AND gate (108) is opened, and the output of the NOR gate (107) is different through the resistor (124) in the waveform as shown in FIG. 9 (e). It is input to the common mode input terminal of the dynamic amplifier (109).

On the other hand, the output of the AND gate (108) is input to the integrated value hold circuit (110). This integrated value hold circuit (110)
Then, the input signal is integrated, and the value of the integrated waveform shown in FIG. 9 (f) is smoothed and output. At this time, when the frequency of the input signal is low, the output voltage is high, and when the frequency is high, the output voltage is low. The above AND which is an input signal
The frequency of the output of the gate (108) is twice the frequency of the rotation pulse, and the frequency of the rotation pulse is proportional to the rotation speed of the capstan motor (81). That is, the output voltage of the integrated value hold circuit (110) (FIG. 9 (f)) is low when the rotation speed of the capstan motor (81) is high, and is high when the rotation speed is low.

The switch in the integrated value hold circuit (110)
It is opened to hold the output voltage before the still operation at the still time. A bias potential is applied to the output of the integrated value hold circuit (110) through the resistor (125) by the bias power supply (111), and the inverting input terminal of the differential amplifier (109) is as shown in FIG. 9 (g). It is input with a simple waveform. as a result,
As shown in FIG. 9 (h), the output of the differential amplifier (109) rises when the cycle of the rotation pulse becomes shorter (when the rotation speed becomes higher), which is the control terminal (83) of the capstan motor (81). ) Is entered.

In the control circuit described above, the mono-multivibrator (101), (104) and the NOR gate (107) provide a non-driving section for a predetermined time from the rise and fall of the rotation pulse, and then generate the pulse. The capstan motor (81) is driven by using this as a drive wave.

Further, the counter (121) and the counter (122) are counters for performing variable speed by intermittent driving, and one counter (121) determines a time for performing slow reproduction,
The other counter (122) determines the still reproduction time. During slow playback, the output of the counter (121) is "L", and at this time the counter (122) is reset,
Its output is also "L". When a certain time elapses, that is, when a predetermined number of pulses are input from the oscillator (120), the output of the counter (121) becomes “H” and the head movement amplitude adjustment terminal (79) becomes “H”. A signal is derived and the head movement amplitude becomes the value from slow to still. Also, AND
Since the gate (108) is also closed, the drive waveform as described above is not output and the capstan motor (81) stops. Furthermore, the reset of the counter (122) is released,
Start counting. When a predetermined number of pulses are input from the oscillator (120), the output of the counter (122) becomes "H" and the counter (121) is reset and then starts counting. Output of the counter (121) "L" Therefore, A
The ND gate (108) is opened and the drive wave as described above is input to the capstan motor (81), and the capstan motor (81) starts rotating. The "L" K signal is also input to the head movement amplitude adjustment terminal (79), and the head movement amplitude becomes the value from the still to slow state. In this way, slow reproduction is restarted. By repeating this operation, a slower speed than that of slow playback is possible.

The drive waveform of the capstan motor (81) shown in FIG. 7 is as shown in FIG. 9 (h).
The rotation pulse of 1) is driven by two pulses per cycle.

Since the number of rotation pulses is n / 60 per field, the capstan motor (81) is driven by n / 30 pulses per field. In general, n is very large, and according to this driving method, the capstan motor (81) is driven by a plurality of pulses per field.

If the capstan motor (81) is driven with multiple pulses per cycle as described above, the capstan motor (8
1) rotates stably at low speed.

FIG. 8 is a control circuit of a capstan motor in a slow speed reproducing device according to another embodiment of the present invention. In FIG. 8, (130) is the NOR gate (107) and A in FIG.
An oscillator added between the ND gate (108), this oscillator (130) is only when the output of NOR gate (107) is "H".
It oscillates at an oscillation frequency determined by the resistors (131) and (132) and the capacitor (133). Since other configurations are the same as those in FIG. 7, the same reference numerals are given and description thereof is omitted.

The output waveform of the differential amplifier (109) in the control circuit shown in FIG. 8 is as shown in (h1) of FIG. 9, and this is the drive waveform of the capstan motor (81), which is the control terminal (83). Entered in.

In FIG. 8, the capstan motor (81) is driven by a large number of pulse trains per one cycle of the rotation pulse of the capstan motor (81), but according to this, more stable low speed rotation can be obtained. .

In the control circuit of FIGS. 7 and 8 above, by appropriately selecting the times of the counter (121) and the counter (122), the slow reproduction time and the still reproduction time can be arbitrarily changed to allow a wide range of operations. Slow playback of variable speed can be performed.

1 to 4, only one head (5) is shown on the upper drum (3) for the sake of simplification of description, but another head (5) is opposed to the upper drum (3). A magnetic head is fitted and these two magnetic heads (5
The control circuit for a) and (5b) is shown in FIG.
Each two of the four contactors supplies a control current to the cylindrical coils (42a), (42b) of the drive unit of the respective magnetic head.

Although the electrode (15) is shown as being integrated with the pedestal (9), it may not be integrated.

As described above, according to the present invention, a pair of rotary heads for reproducing a video signal recorded on a magnetic tape, an elastic member for supporting the rotary heads, and an elastic member mounted on the elastic member. A coil and a magnet device arranged corresponding to this coil, and by applying a signal according to the speed of the coil magnetic tape, the rotary head works with the magnetic tape in cooperation with the magnet device. , A rotary drum capable of displacing in the width direction, a rotary pulse generator for outputting a pulse train proportional to the rotation speed of a capstan motor for driving the magnetic tape, and a predetermined pulse synchronized with the pulse edge of the pulse train. No voltage is applied to the capstan motor for a predetermined time from the edge, and voltage is applied to the capstan motor until the next pulse edge after the predetermined time. Since the capstan motor is intermittently driven with a control device, it is possible to realize high-quality playback without noise or blur even when the tape playback speed is slower than 1/2 of the normal feeding speed. Have an effect.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a rotary drum which is a constituent element of a slow speed reproducing device according to an embodiment of the present invention.
FIG. 4 is a plan view thereof, FIG. 3 is a vertical cross-sectional view showing the main part in more detail, FIG. 4 is a bottom view of FIG. 3, FIG. 5 is a control circuit diagram of a rotary drum, and FIG. 7 is a control circuit diagram of a capstan motor, FIG. 8 is a control circuit diagram of a capstan motor according to another embodiment of the present invention, and FIG. 9 is a waveform diagram of each part. FIG. 10 is a longitudinal sectional view showing a main part of a rotary drum in a conventional slow speed reproducing device, and FIG. 11 is a view for explaining a relative locus between a tape and a head in a VTR. (2), (3) ... upper and lower drums, (4a) ... drive unit,
(5), (5a), (5b) ... Head, (7), (8) ... Vertical transformer, (13) ... Tape, (14), (14-1),
(14-2), (14-3) ... Contact, (15), (15-
1), (15-2), (15-3) ... electrode, (41) ... spring,
(42), (42a), (42b) ... Cylindrical coil, (43) ... Cylindrical permanent magnet, (80) ... Capstan, (81) ... Capstan motor, (84) ... Rotation pulse generator, ( 101),
(104) ... mono multivibrator, (107) ... NOR gate, (108) ... AND gate, (109) ... differential amplifier, (12
1), (122) ... Counter. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A pair of rotary heads for reproducing a video signal recorded on a magnetic tape, an elastic member for supporting the rotary heads, a coil mounted on the elastic member, and a coil corresponding to the coil. A magnetic device is provided, and by applying a signal according to the speed of the magnetic tape to the coil, the rotary head can be displaced in the width direction of the magnetic tape in cooperation with the magnet device. A rotary drum, a rotary pulse generator that outputs a pulse train proportional to the number of revolutions of a capstan motor that drives the magnetic tape, and a predetermined time from the predetermined pulse edge to the capstan motor in synchronization with the pulse edge of the pulse train. The capstan motor is provided with a control device that applies a voltage to the capstan motor after the predetermined time until the next pulse edge, without applying a voltage. Slow reproduction apparatus being characterized in that the over data to be intermittently driven.