JPH0664789B2 - Video tape recorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described in the following order.

A. Industrial application fields B. SUMMARY OF THE INVENTION C. Conventional Technology D. Problems to be Solved by the Invention E. Means for Solving Problems F. Action G. Example G-1 configuration G-2 operation H. Effect of Invention A. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention sequentially records a pilot signal whose frequency cyclically changes for each track and reproduces the frequency of a reproduction pilot signal reproduced from an adjacent track to a track to be tracked by a head and a reference pilot. The present invention relates to a video tape recorder having a function of detecting a signal component having a frequency different from the frequency of a signal, obtaining a tracking error signal of the head based on this signal component, and performing tracking control.

B. SUMMARY OF THE INVENTION According to the present invention, a pilot signal whose frequency cyclically changes for each track is sequentially recorded, and a frequency of a reproduction pilot signal reproduced from an adjacent track to a track to be tracked by a head during reproduction and a reference pilot signal. In a video tape recorder having a function of detecting a signal component having a frequency difference from the frequency and obtaining a tracking error signal of the head based on this signal component to perform tracking control, the tracking control function is used. By stopping the running of the magnetic tape while the head is tracking the predetermined recording track and switching the operation mode, it is possible to prevent the image from being disturbed due to the switching of the operation mode.

C. 2. Description of the Related Art In a so-called helical scan type video tape recorder that records and reproduces a video signal by using a rotary magnetic head device, recording tracks formed on a magnetic tape at a predetermined inclination angle with respect to a tape running direction. A video signal is sequentially recorded, for example, one field at a time, and the reproducing track is traced by the rotary magnetic head when the recording track is traced by the rotary magnetic head during reproduction. Further, conventionally, in the video tape recorder, in addition to the normal reproduction operation in which the reproduction operation is performed at the regular tape traveling speed, the reproduction operation can be performed by traveling the tape at a high speed or a low speed different from the regular tape traveling speed. Variable speed playback operation,
There is provided one having various functions such as a reverse playback operation in which a tape is run in a reverse direction to perform a playback operation in order to search for a target image.

In the helical scan type video tape recorder as described above, as a method for performing tracking control of the rotary magnetic head with respect to the recording track on the magnetic tape, a control track is provided on the magnetic tape, and the control track is provided at the position of the recording track of the video signal. A so-called CTL system for controlling the drive amount and timing of the capstan for tape running drive and the brake amount and its timing by recording the corresponding control signal by using the control signal, and the track of the video signal A so-called A in which a pilot signal whose frequency cyclically changes for each time is recorded by being superimposed on a video signal, and tracking control is performed using the pilot signal
The TF method and the like have been conventionally known. The ATF type tracking control device is disclosed in, for example, Japanese Patent Laid-Open No. 59-659.
No. 62 publication.

Further, generally, various electrically configured signal processing circuits such as a servo control circuit of a tape running system and a tracking control circuit of a magnetic head are switched, and a switching operation of a mechanical portion such as a drive mechanism of a reel base is performed. As a result, the video tape recorder is operated in the operation mode corresponding to the above various functions.

D. Problems to be Solved by the Invention Generally, in the helical scan type video tape recorder, if the tracking is deviated during the reproducing operation, a reproduced image with good image quality cannot be obtained, and the tracking is deviated each time the operation mode is switched. As a result, it becomes impossible to obtain a reproduced image with good image quality until proper tracking control is performed. In particular, since the switching drive of the mechanical portion cannot be performed as quickly as the switching of the electric circuit, the image is disturbed for a long time during the switching drive period of the mechanical portion.

E. Means for Solving the Problems In order to solve the above-mentioned problems, the video tape recorder according to the present invention sequentially records a pilot signal whose frequency cyclically changes for each track, and the head tracks the signal during reproduction. Detects a signal component having a frequency that is the difference between the frequency of the reproduction pilot signal reproduced from the adjacent track and the frequency of the reference pilot signal, and obtains the tracking error signal of the head based on this signal component to perform tracking. It is provided with a tracking control means for controlling and a stop control means for stopping the tape running while the head is tracking the target recording track by the tracking control means. The first invention, as shown in the flowchart of FIG. 1A, is a stop control for controlling the tape running in a state in which a predetermined recording track is tracked by the operation of the tracking control means and the stop control means. When the mode is switched from one operation mode to another operation mode via the mode, the tracking error signal is superimposed on the speed error signal for speed control of the tape drive means via the gain switching circuit, and It is characterized in that the gain switching circuit is controlled so that the gain in the stop control mode is higher than those in the operation mode of 1 and other operation modes, and the tape transfer control is performed by the pit signal. The second invention is, as shown in the flowchart of FIG. 1B, when the mode is switched from one operation mode to another operation mode, the tracking error signal is supplied to the tape drive means via the gain switching circuit. And the gain control circuit controls the gain switching circuit so that the gain in the stop control mode is set to be higher than that of the operation mode of 1 and other operation modes. Tracking control is performed, and after the tape is stopped, the frame feed operation is performed at least once while performing the tracking control by the tracking error signal with the gain increased, and then the mode is switched to another operation mode. . In the second invention, as shown in the flow chart of FIG. 1B, a pilot signal whose frequency cyclically changes for each track is sequentially recorded, and when reproducing, the head reproduces from the adjacent track to the track to be tracked. Tracking control means for detecting a signal component having a frequency difference between the frequency of the reproduced pilot signal and the frequency of the reference pilot signal, and performing tracking control by obtaining the tracking error signal of the head based on this signal component, The tracking control means is provided with a stop control means for stopping the tape running in a state where the head is tracked to a target recording track, and the tape is kept tracking to a predetermined recording track by the operation of the tracking control means and the stop control means. Stops driving and performs field still playback. When the mode is switched from the forward playback operation mode to the reverse playback operation mode via the playback mode, the tracking error signal is converted into a speed error signal for speed control of the tape drive means via the gain switching circuit. While superimposing, the gain switching circuit is controlled to make the gain of the stop control mode larger than that of the forward reproduction operation mode and the reverse reproduction operation mode, and tracking control is performed by the tracking error signal with increased gain, and after the tape is stopped. The feature is that the frame feed operation is performed at least once while performing the tracking control by the tracking error signal with the increased gain, and then the still reproduction mode is entered, and the mode switching mechanism is operated during the still reproduction mode. I am trying.

F. In the video tape recorder according to the present invention, the tracking control means is a tracking error signal formed by a frequency signal component of a difference between the frequency of the reproduction pilot signal reproduced from the recording track on the magnetic tape and the frequency of the reference pilot signal. Based on, the tracking control is performed so that the head traces the center of the target recording track. Further, the stop control means stops the tape running while the predetermined recording track is being tracked by the operation of the tracking control means and the stop control means.

Then, when the mode is switched from one operation mode to another operation mode, the tracking error signal is superimposed on the speed error signal for speed control of the tape driving means via the gain switching circuit, and the gain switching is performed. By controlling the circuit, the gain of the stop control mode is set to be larger than that of the operation mode of 1 and other operation modes, the tracking control is performed by the tracking error signal with increased gain, and after the tape is stopped, by the tracking error signal with increased gain. The frame feed operation is performed at least once while performing the tracking control, and then the mode is switched to another operation mode.

The gain switching circuit outputs the tracking error signal when the mode is switched through the stop control mode in which the tape running is controlled in a state where the predetermined recording track is tracked by the operations of the tracking control means and the stop control means. Via the speed error signal for controlling the speed of the tape drive means, and controlling the gain switching circuit so that the gain in the stop control mode is larger than that in the 1 operation mode and other operation modes. As a result, the tape transfer control by the pilot signal in frame feeding after the tape is stopped is ensured, and the relative positional relationship between the recording track on the magnetic tape and the head is always constant at the start of the operation of the new operation mode.

Also, through the still reproduction mode in which the tape running is stopped and the field still reproduction is performed in the state where the predetermined recording track is tracked by the operation of the tracking control means and the stop control means, the forward reproduction operation mode and the reverse reproduction operation mode are performed. When the mode is switched to the operation mode, the tracking error signal is superposed on the speed error signal for speed control of the tape drive means via the gain switching circuit, and the gain switching circuit is controlled to control the stop control mode. The gain of is set to be larger than the forward playback operation mode and the reverse playback operation mode, tracking control is performed by the tracking error signal with increased gain, and after the tape is stopped, the frame feed is performed while performing the tracking control by the tracking error signal with increased gain. Do the action at least once Enters the still reproduction mode, by operating the mode switching mechanism during the still reproduction mode, an image reproduction field still during the operation of the mode switching mechanism is carried out.

G. Embodiment An embodiment of the video tape recorder according to the present invention will be described in detail below with reference to the drawings.

The embodiment shown in FIGS. 2 to 9 is an application of the present invention to a video tape recorder for so-called 8 mm video.

G-1 Structure In the block diagram of FIG. 2 showing the electric structure of the reproducing system of the video tape recorder of this embodiment, the magnetic tape 1 is used.
Is mounted on the outer circumference of the rotary magnetic head device 2 in the form of Ω, and is sandwiched by a pinch roller 3 and a capstan shaft 4 arranged on the downstream side of the rotary magnetic head device 2 to be held by the capstan shaft 4.
Is loaded into a predetermined tape path by loading means (not shown) so that it can be run while slidingly contacting the outer circumference of the rotary magnetic head device 2 by being rotationally driven by the capstan motor 5. The running speed of the magnetic tape 1 is detected by a frequency generator 6 which outputs a frequency signal according to the rotation speed of the capstan shaft 4.

In this embodiment, in the rotary magnetic head device 2, three magnetic heads 8A, 8B, 8A 'are arranged on a head drum 7 which is rotated at a constant speed by a head driving motor (not shown). A reproduction RF output obtained by sequentially tracing the recording tracks TR on the magnetic tape 1 at 8A, 8B and 8A 'is output via the rotary transformer 9.

Here, as shown schematically in FIG. 3, the magnetic tape 1 has four kinds of frequencies f ₁ , on the recording tracks TR which are sequentially formed with a predetermined inclination with respect to the tape running direction.
A pilot signal that cyclically repeats f ₂ , f ₃ , and f ₄ is recorded by being superimposed on the video signal. Frequency _{f 1, f 2, f 3} , f 4 of the pilot _{signal, | f 1 -f 2 | =} | f 3 -f 4 | = Δfa | f 2 -f 3 | = | f 1 -f 4 | It is set so as to satisfy the relation of the first expression of = Δfb. Then, the three magnetic heads 8 of the rotary magnetic head device 2 are
A, 8B, 8A 'of symmetrically arranged first and second
Of the magnetic heads 8A and 8B, the azimuths of the magnetic gaps are different from each other, and the odd-numbered recording tracks TR ₁ and TR ₃ on the magnetic tape 1 are traced by the first magnetic head 8A and the even-numbered Recording track TR
₂ and TR ₄ are traced by the second magnetic head 8B and are used for performing normal recording / reproducing operations. Further, the second magnetic head 8A 'disposed on one side of the second magnetic head 8B has the same azimuth magnetic gap as the first magnetic head 8A, and the first magnetic head It is used to perform a field still reproduction operation by tracing the odd-numbered recording tracks TR _2n- 1 on the magnetic tape 1 alternately with 8A.

A reproduction RF output signal obtained by the rotary magnetic head device 2 is taken out from the rotary transformer 9 via an RF switch circuit 10 and reproduced via a preamplifier 11 to a reproduction video signal processing circuit 12 and an error signal forming circuit. Is being supplied to 14.

Here, the RF switch circuit 10 includes a first switch 10A for switching between the second magnetic head 8B and the third magnetic head 8A ', and the second or third switch selected by the first switch 10A. Magnetic head 8B,
8A 'and the first magnetic head 8A are alternately selected by a second switch 10B. The first switch 10A is controlled by an operation mode designating signal which designates an operation mode of the video tape recorder of this embodiment, and the second magnetic head 8 is operated during a normal reproducing operation.
B is selected, and the third magnetic head 8A 'is selected in the still reproduction operation mode. Further, the second switch 10B is used for the rotary magnetic head device 2
The switching operation is performed according to the PG pulse whose level is inverted every 1/2 rotation in synchronism with the above rotation.

The reproduction video signal processing circuit 12 includes the switch circuit 1
The reproduction RF output signal supplied via 0 is subjected to predetermined signal processing to form a reproduction video signal, and this reproduction video signal is output from the reproduction output terminal 13.

Further, the error signal forming circuit 14 is supplied with the reference pilot signal from the reference pilot signal generating circuit 15, and based on the reference pilot signal and the reproduction pilot signal included in the reproduction RF output signal, a tracking error signal is generated. And the error signal is supplied to the signal mixing circuit 17 via the gain switching circuit 16. The reference pilot signal generation circuit 15 is controlled by the pilot signal switching circuit 18 to which the operation mode designating signal and the PG pulse are supplied, and the reference pilot signals of the predetermined four kinds of frequencies ₁ , ₂ , ₃ , ₄ are generated. Signals are sequentially supplied to the error signal forming circuit 14.

Here, as the error signal forming circuit 14, for example, the one having the structure shown in FIG. 4 is used.

In FIG. 4, a reproduction RF output signal is supplied to the first signal input terminal 101 from the preamplifier 11 and the second signal output terminal 102 is supplied from the reference pilot signal generator 15 to the reference pilot signal. Signal is supplied.
The reproduction RF output signal is a low-pass filter 103 for extracting a reproduction pilot signal component included in the reproduction RF output signal.
From the first signal input terminal 101 through the multiplication circuit 1
04. The multiplication circuit 104 includes the second
The reference pilot signal is supplied from the signal input terminal 102. The output of the multiplication circuit 104 is the first and second difference frequency Δa, Δb detection circuits 105, 1
It is supplied to 06. The first difference frequency Δa detection circuit 105 extracts the component of the frequency Δa shown in the above-mentioned first expression contained in the output of the multiplication circuit 104 and supplies it to the first DC conversion circuit 107. In addition, the second difference frequency Δb detection circuit 105 is the multiplication circuit 10
The frequency component Δb shown in the above-mentioned first equation contained in the output of No. 4 is taken out and supplied to the second direct-current converting circuit 108. Then, the first and second difference frequencies Δa and Δ obtained by the respective DC conversion circuits 107 and 108.
The DC level signal of the component of b is supplied to the subtraction circuit 109. The output of the subtraction circuit 109 is supplied to the signal selection switch 111 directly and via the polarity inversion circuit 110, and the signal selection switch 111 outputs the buffer amplifier 112.
Is given to the signal output terminal 113 via. The signal selection switch 111 is adapted to perform a selection operation according to the RF pulse.

Further, the gain switching circuit 16 switches the gain of the tracking error signal obtained by the error signal forming circuit 14 and supplies it to the signal mixing circuit 17, and in the still operation mode, it is more than in the normal operation mode. A tracking error signal having a large gain is supplied to the signal mixing circuit 17.

Furthermore, the signal mixing circuit 17 frequency-converts the output of a frequency generator 6 that generates a frequency signal according to the rotational speed of the capstan motor 5 that drives the capstan shaft 4 that drives the magnetic tape 1, that is, the tape speed. A speed error signal obtained by converting it into a voltage signal by the voltage converter 19 is supplied, and the speed error signal and the tracking error signal are mixed. The output of the signal mixing circuit 17 is supplied to the capstan motor drive circuit 21 via the buffer amplifier 20. Further, the capstan motor drive circuit 21 is supplied with a DC drive bias voltage from each of the bias circuits 23 and 24 via the first mode switching circuit 22, and via the second mode switching circuit 25. A drive control signal that specifies the drive and rotation direction of the capstan motor 5 is supplied from the timing control circuit 26. In this embodiment, the capstan motor drive circuit 21
A starting circuit 27 whose operation is controlled by the output of the frequency generator 6 is connected to the.

In the reproducing system of the video tape recorder of this embodiment, when the operation mode of the reproducing system is switched by the system controller (not shown), the operation mode designating signal for designating the still reproducing operation mode is the first control input terminal. The signal is supplied from 31 to the RF switch circuit 10, the gain switching circuit 16, the pilot signal switching circuit 18, the first and second mode switching circuits 22 and 25, and the timing control circuit 26. Further, a PG pulse whose level is inverted every 1/2 rotation in synchronization with the rotation of the rotary magnetic head device 2 is output from the second control output terminal 32 to the RF switch circuit 10, the error signal forming circuit 14, and the pilot signal switching circuit. 18 and the timing control circuit 26.

Here, the video tape recorder of this embodiment is provided with an operation mode switching mechanism having a configuration as shown in FIGS. 5 to 7.

In this embodiment, a contact gear 202 provided with a contact switch is rotatably attached to the take-up reel base 201. This contact gear 202 is used for the control motor 2
It is rotationally driven by 03 via the reduction gear 204. The contact gear 202 includes a slider drive gear 205.
Are meshed. Then, this slider drive gear 20
5 is a rack 207 of the mode switching slider 206.
Meshes with. The mode switching slider 206
When the contact gear 202 is rotated to a position according to a desired operation mode by the rotational drive of the control motor 3, the contact gear 202 slides in the directions of arrows A and B in FIG. 5 to eject, load / unload. It is moved to 6 positions (modes) of loading, FF (fast forward), REW (rewind), stop, FWD (forward playback), REC (recording), and REV (reverse playback). Then, by sliding the slider 206, a predetermined lever is actuated to press the pinch roller 3 against the capstan shaft 4, set a tension regulator or a swing gear, operate various brakes, etc. Switching to the operating mode is performed.

Then, in the FWD mode in which the magnetic tape 1 is run in the forward direction at the regular tape speed to perform the reproducing operation, the mode switching slider 206 is moved to the rightmost side, as shown in FIG. The brake release arm 21 is provided by one of a pair of cams 210A and 210B formed in a V shape on the mode switching slider 6.
By pushing the pin 212 of No. 1 and pushing down the brake release slider 213, the main brakes 215, 216 for the reel stands 201, 214 are released.

In the REV mode in which the magnetic tape 1 is run in the reverse direction to perform the reproducing operation, the mode switching slider 6 is moved to the leftmost side, so that the mode switching slider is moved as shown in FIG. The other side of the pair of cams 210A and 210B formed in the shape of a V in FIG.
01, 214 for each main brake 215, 216
Is to be released.

G-2 Operation In the video tape recorder having the above-described configuration, the tracking error signal forming circuit is used in the forward reproduction operation in which the magnetic tape 1 is moved in the forward direction at the regular tape speed to perform the reproduction operation. The tracking error signal obtained at 14 is supplied to the signal mixing circuit 17 with its gain reduced by the gain switching circuit 16.
Then, the signal mixing circuit 17 uses the speed error signal supplied from the frequency / voltage converter 19 as a main error signal, and the capstan motor drive circuit 21.
Return to. The capstan motor 5 driven by the capstan motor drive circuit 21 is subjected to speed servo by the speed error signal supplied as the main error signal, and tracking servo by the tracking error signal whose gain is reduced. Then, the magnetic tape 1 is moved in the forward direction so that the recording track TR on the magnetic tape 1 is correctly tracked by the magnetic heads 8A and 8B.

In the forward reproduction operation mode, as shown in the timing chart of FIG. 8, the above-mentioned predetermined frequencies ₁ , ₂ ,
Tracking control is performed so that reproduction RF outputs of the video signals on which the pilot signal signals ₃ and ₄ are superimposed are sequentially obtained.

If a switching operation to the reverse reproduction operation mode is performed at the timing ts in FIG. 8 during the forward reproduction operation, a control signal for instructing this mode switching is sent from the system controller (not shown). It is supplied to the first control input terminal 31, and first, the control operation of the field still reproduction operation mode is performed. Then, after this timing ts, after one frame period elapses from the timing t _{0 at} which the reproduction pilot signal of the frequency of _{1 is first} obtained by the _first magnetic head 8A, the frame feeding of one frame is performed and the next _{1 is} obtained. At the timing t ₁ at which the reproduction pilot signal of the frequency is obtained, the operation mode specifying signal for specifying the still reproduction operation mode is sent from the system controller (not shown) to the first control input terminal 31.
Is supplied to the first switch 10 of the RF switch circuit 10 to select the third magnetic head 8A ′, and the gain switching circuit 16 outputs the tracking error signal obtained by the tracking error forming circuit 14. The gain is controlled to be increased and supplied to the signal mixing circuit 17, and a constant brake signal is supplied from the timing control circuit 26 via the second mode switching circuit 25.

The constant braking signal from the timing control circuit 26 is supplied to the capstan motor driving circuit 21, ₁
Recording track TR _{1 from} which a reproduction pilot signal having a frequency of
The capstan motor 5 is stopped so that the still trace is performed at A '.

Here, in this embodiment, in consideration of the positional deviation caused by stopping the magnetic tape 1 from the normal tape speed, the recording track TR is still-recorded by the first and third magnetic heads 8A and 8A '. After the capstan motor 5 is stopped so as to trace, the frame feeding operation is further performed once. In this frame feeding operation, the starting circuit 2
7. The capstan motor drive circuit 2 is used to set the starting voltage according to 7.
1 to rapidly raise the rotation speed of the capstan motor 5 to perform tracking control by the tracking error signal with the increased gain, and one frame, that is, 2
The capstan motor is configured so that the recording track TR _{3 from} which the reproduction pilot signal having the frequency of ₃ is obtained by sending the magnetic tape 1 by the number of tracks is still traced by the first and third magnetic heads 8A and 8A '. 5 is stopped. Then, field trace reproduction is performed by still tracing the recording track TR by the first and third magnetic heads 8A and 8A 'as shown by the solid line arrow in FIG. I do.

The tracking control in this embodiment is based on a pilot signal cyclically repeating a predetermined frequency ₁ , ₂ , ₃ , ₄ recorded on each recording track TR of the magnetic tape 1 based on a reproduction pilot signal and a reference pilot signal. By controlling the closed loop based on the relative error signal level formed from the signal level of the frequency component of the difference between and, there is no influence on the absolute value of the output of each magnetic head 8A, 8B. In addition, the tracking control signal using the tracking error signal with the increased gain ensures the tape transfer control with respect to the change of the pilot signal, and the magnetic heads 8A and 8B.
Can be accurately tracked on the target recording track TR and can be reliably stopped by a brake signal at a constant timing, and a field still image with extremely high image quality can be reproduced.

Then, the field still reproduction operation is performed to reproduce a high-quality field still image on the monitor screen, and during the field still reproduction operation period, the control motor 203 is driven to drive the mode switching slider 206. Is moved to the position of the above-mentioned reverse reproduction operation mode. Then, the mode switching slider 206
Is confirmed to have moved to a predetermined position by a system controller (not shown), and the operation in the reverse playback operation mode is started.

As described above, in the still reproduction operation mode, the magnetic tape 1
Since the relative positional relationship between the upper recording track TR and each magnetic head 8A, 8B, 8A 'of the rotary magnetic head device 2 is specified, the operation mode is switched via the still reproduction operation mode. As a result, the operation in the new operation mode after the operation mode switching can always be quickly started from the specific initial state.

Further, the mode switching from the forward reproduction operation mode to the reverse reproduction operation mode is performed through the still reproduction mode for performing field still reproduction as in this embodiment, and the mode switching slider is operated during the still reproduction mode. By moving 206 from the position of the forward reproduction operation mode to the position of the reverse reproduction operation mode, a field still image with good image quality is reproduced on the monitor screen while the mode switching slider 206 is moving. It is possible to smoothly shift from the field still reproduced image to the backward reproduced image.

H. EFFECTS OF THE INVENTION As is clear from the above description of the embodiments, in the video tape recorder according to the present invention, the tracking control means controls the frequency of the reproduction pilot signal reproduced from the recording track on the magnetic tape and the frequency of the reference pilot signal. Based on the tracking error signal formed by the difference frequency signal component, tracking control is performed so that the head traces the center of the target recording track, and the stop control means causes the tracking control means to track a predetermined recording track. Since the tape running is stopped in this state, the operation of the tracking control means and the stop controlling means controls the tape running in the state where the tape is tracked to a predetermined recording track. To switch to another operating mode At this time, the tracking error signal is superimposed on the speed error signal for speed control of the tape driving means via the gain switching circuit, and the gain switching circuit is controlled to set the gain in the stop control mode to 1 operation mode. And it is not larger than other operation modes, and tracking control by the tracking error signal with increased gain is performed.
After the tape is stopped, the frame feed operation is performed at least once while performing the tracking control by the tracking error signal with the increased gain, and then the mode is switched to another operation mode, so that the tape is fed by the pilot signal in the frame feed after the tape is stopped. The transfer control becomes reliable, and the operation in the new operation mode after switching the operation mode can always be quickly started from a specific intended state.

Also, through the still reproduction mode in which the tape running is stopped and the field still reproduction is performed in the state where the predetermined recording track is tracked by the operation of the tracking control means and the stop control means, the forward reproduction operation mode and the reverse reproduction operation mode are performed. When the mode is switched to the operation mode, the tracking error signal is superposed on the speed error signal for speed control of the tape drive means via the gain switching circuit, and the gain switching circuit is controlled to control the stop control mode. The gain of is set to be larger than the forward playback operation mode and the reverse playback operation mode, tracking control is performed by the tracking error signal with increased gain, and after the tape is stopped, the frame feed is performed while performing the tracking control by the tracking error signal with increased gain. Do the action at least once , Enter the still playback mode, and by operating the mode switching mechanism during the still playback mode, if there is very little screen disturbance, the playback screen from the forward playback operation is switched to the reverse mode via the field still screen. It is possible to smoothly shift to the reproduction screen by the direction reproduction operation.

[Brief description of drawings]

FIG. 1A is a flowchart showing the principle of the first invention, and FIG. 1B is a flowchart showing the principle of the second invention. FIG. 2 is a block diagram showing an embodiment of a video tape recorder to which the tracking control device according to the present invention is applied, and FIG. 3 is a schematic diagram showing a recording format of the magnetic tape in the above embodiment, and a fourth embodiment. FIG. 5 is a block diagram showing the configuration of the error signal forming circuit in the above embodiment, FIG. 5 is a schematic plan view showing the mechanical configuration of the video tape recorder of this embodiment, and FIG. 6 is a forward reproduction. FIG. 7 is a plan view of relevant parts showing the position of the mode switching slider in the operation mode, FIG. 7 is a plan view of relevant parts showing the position of the mode switching slider in the reverse reproduction operation mode, and FIG. FIG. 9 is a timing chart for explaining the operation of the example, and FIG. 9 also shows a trace locus for each magnetic head in the field still reproduction operation mode. Is an expression view. 1 ... Magnetic tape 2 ... Rotating magnetic head device 4 ... Capstan shaft 5 ... Capstan motor 6 ... Frequency generator 8A, 8B, 8A '... Magnetic head 10 ... RF switch circuit 14 ... Error Signal forming circuit 15 ... Reference pilot signal generating circuit 16 ... Gain switching circuit 17 ... Signal mixing circuit 21 ... Capstan motor drive circuit 26 ... Timing control circuit 203 ... Control motor 206 ... Mode switching slider

Continuation of the front page (56) Reference JP-A-60-20346 (JP, A) JP-A-60-89851 (JP, A) JP-A-60-89181 (JP, A) JP-A-623-3576 (JP , A) Actual development Sho 58-123283 (JP, U)

Claims (2)

[Claims] 1. A frequency of a reproduction pilot signal and a frequency of a reference pilot signal reproduced from an adjacent track to a track to be tracked by a head during reproduction by sequentially recording a pilot signal whose frequency cyclically changes for each track. A tracking control means for detecting a signal component having a difference frequency, obtaining a tracking error signal of the head based on this signal component and performing tracking control, and tracking the head to a target recording track by the tracking control means. A stop control means for stopping the tape running in a state where the tape running is controlled by the operation of the tracking control means and the stop controlling means to stop the tape running in the state of tracking a predetermined recording track.
When the mode is switched from the first operation mode to the other operation mode, the tracking error signal is superposed on the speed error signal for speed control of the tape driving means via the gain switching circuit, and the gain switching circuit is operated. By controlling the gain of the stop control mode to be larger than that of the operation mode of 1 and other operation modes, tracking control is performed by the tracking error signal with increased gain, and after the tape is stopped, tracking control by the tracking error signal with increased gain is performed. The video tape recorder is characterized in that the frame feed operation is performed at least once while performing the above operation, and then the mode is switched to another operation mode. 2. A frequency of a reproduced pilot signal reproduced from an adjacent track to a track to be tracked by a head during reproduction, and a frequency of a reference pilot signal, by sequentially recording a pilot signal whose frequency cyclically changes for each track. A tracking control means for detecting a signal component having a difference frequency, obtaining a tracking error signal of the head based on this signal component and performing tracking control, and tracking the head to a target recording track by the tracking control means. A still playback mode in which the tape running is stopped and the tape running is stopped while the tape is being tracked to a predetermined recording track by the operation of the tracking control means and the stop control means. Through forward playback operation mode When the mode is switched to the reverse reproduction operation mode, the tracking error signal is superimposed on the speed error signal for speed control of the tape drive means via the gain switching circuit, and the gain switching circuit is controlled. The gain of the stop control mode is set to be larger than that of the forward reproduction operation mode and the reverse reproduction operation mode, tracking control is performed by the tracking error signal with increased gain, and tracking control by the tracking error signal with increased gain is performed after the tape is stopped. At least one frame feed operation while performing
A video tape recorder, characterized in that the mode switching mechanism is operated during the still reproduction mode after the operation is repeated.