JPH03127363A - magnetic recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a magnetic recording/reproducing device.

BACKGROUND OF THE INVENTION In recent years, magnetic recording and reproducing devices have been developed using V
Many H8 or VH8-C camera-integrated cameras are on the market. In such a servo system, a state called back-tracking playback theoretically exists, and there is a problem in that a non-negligible jitter level occurs even in the amount of self-recording and playback. Here, the details of the servo system will be omitted as they are generally known, but
The above-mentioned back tracking playback will be explained with reference to the drawings.

lal in Figure 3 is VH3 (VH3
This is a schematic diagram illustrating the recording method (only relevant parts are shown) of the recording method (including C... the same applies hereafter), in which the control track al+a2 is the reproduction control signal (hereinafter referred to as PBCTL) used for the reproduction servo. ). As a VH3 type servo system, PB CT
L al + a2 are considered to be the same without any distinction, and the phase is controlled, so the track recorded by the A head can be changed to A or A.
'The servo is controlled normally no matter which head is used for playback. Therefore, even though self-edge playback is performed, there is a probability of 172 that the recording and playback tracks are different. This state in which different tracks are operated during recording and playback is called back tracking playback.

Note that the state in which recording and reproduction are performed on the same track will be referred to as front tracking reproduction.

A during recording in order to improve jitter by eliminating the above-mentioned back tracking playback.

There is a method of making it possible to distinguish between one frame of the B head and one frame of the A'B' head, so that it can be determined at the time of reproduction whether back tracking reproduction is being performed.

As shown in FIG. 3(b), the control signal (hereinafter C
The duty ratio of TL (referred to as TL) for one frame of A and B heads has been changed to (60:40) compared to the conventional one (60:40).
5:35) and (60:40) are repeated.

In this case, the PB CTL required for the servo system is not affected. That is, in Fig. 3 (al, a,...
b,:b,, a2=a2. b2:b2. a+
=60: 40, one frame of A, B and A',
There is no distinction between one frame of B'. However, in Figure 3 (
In bl, for example, at b'+: b'+ a2=65: 35a
z b2: b2 at =60:40, and A
, B can be distinguished from A', B'.

Based on the method described above, a conventional example will be described below with reference to the drawings.

FIG. 4 shows a block diagram of the above-mentioned conventional magnetic recording and reproducing apparatus. 1 is a capstan motor driver that drives the capstan motor and generates an FG double signal control signal;
2 is a normal speed/phase controller for controlling the capstan motor during normal times, 3 is a forced accelerator for making front tracking during back tracking, 4 is an acceleration command, and 5 is a back tracking regeneration discriminator (hereinafter referred to as back tracking). (referred to as a tiger discriminator)
It is. During playback, the back tiger discriminator 5 inputs PBC to the input 51.
TL and a head switching signal (hereinafter H8
W) and 1/2 with a period twice that of H3W at the input 53.
2-head switching signal (hereinafter referred to as 1/2H3W)
When inputting and determining back tracking playback, output 54
Outputs an acceleration command start signal to The acceleration command device 4 receives the PB CTL signal from an input 41, the H8W signal from an input 42, the acceleration command start signal from an input 43, and generates an acceleration pulse from an output 44.

Further, the capstan motor driver 1 receives a speed command signal from an input 11, outputs a control signal from an output 12, and outputs a PG multiplied signal from an output 13. The normal speed/phase controller 2 has an FG multiplied signal input 22 from the input 21.
A control signal is input from the output 23, and a speed command signal is output from the output 23. The forced accelerator 3 outputs a speed command signal from the output 31, but whether the capstan motor driver is controlled by the normal speed/phase controller 1 or the forced accelerator 3
The acceleration pulse 44 can be used to switch whether the acceleration pulse 44 is controlled or not.

The operation of the conventional example configured as described above will be explained below.

(i) During recording, as shown in FIG.
The phase relationship between a) and 1/2 HS W (b) is defined, and a recording control signal (hereinafter referred to as RECCTL (OUT)) (C) is recorded for these double numbers. That is, H8W (al is High level/Ll (H) and 1/2HS W (for one frame starting with bl being High level (H), the duty of RECCTL (OUT) is a+b'+:b'+a:= 65:35 and H.S.W.
(For one frame starting with al (H) and 1/2HSWTbl at 10w level (L), RECCTL
(OUT) (The duty of C1 is a2b2: b2
a+=60:40.

0] During reproduction, as shown in Fig. 6, the rising edge of PBCTL (di) is controlled by the action of a normal speed/phase controller so that it is at the center of the slope of the servo error reference signal tel. , PBCTL for servo system
The rising edge of ldl is “+” of the servo error signal reference tel.
This is because when it is in the "" part, it acts in the direction of advancing the phase, and when it is in the "-" part, it acts in the direction of delaying the phase.

Furthermore, H S W (al, 1/2) (S W (bl) has the same phase relationship as in FIG. It is created by the discriminator 5. That is, the relationship is as shown in Table 1 below.

Table 1: Here, L...10w level, H...
High level When PBCTL (d) is in the state shown in FIG. 6, RECCTL (OUT) (C
1 and 1 frame are shifted in phase, resulting in a so-called back tracking playback state.

PB CTL (d
Depending on whether the phase of the rising edge a of one frame of duty-65:35 is in the L or H period, it is possible to determine whether the tracking during playback is on the back side or the front side.

The relationship between the H and L periods of the rising edge AL and the reproduction tracking state is as shown in Table 2 below.

Table 2 As a result of determining whether the playback tracking state is back or front as described above, in the case of back track playback, an acceleration command is output from the back track discriminator 5, inputted to the acceleration command unit 4, and an acceleration pulse ( jl is generated and acceleration of the capstan is started.In addition, in the reversal detector 4, an inversion detection gate signal (hl) is created in synchronization with the H8W signal fat, and is obtained after the capstan is accelerated by the acceleration pulse. PB CTL (
When the rising edge of the acceleration) signal (fl reaches the detection period (High level) of the inversion detection gate signal (hl), the acceleration stop command (i) is output, the acceleration pulse (jl ends, and the capstan acceleration stops). Then, by the action of the normal velocity phase controller, the PBCTL after acceleration (
The rising edge of the acceleration) signal (fl is the servo error reference signal (
e), and the phase inversion operation of the capstan is completed.

Problems to be Solved by the Invention However, in the case of a conventional magnetic recording/reproducing apparatus as shown in FIG. The control of the driver l is switched from the normal velocity phase controller 2 to the forced accelerator 3. At that time, the forced accelerator 3 is
PG signal 1 output from capstan motor driver 1
2 and the speed command signal 31 regardless of the control signal 22.
In order to output the After the control returns to the normal speed phase controller 2, it takes time for the PB CTL (acceleration) (f) to pull into the center of the servo error signal reference te+.As shown in FIG. PB during the acceleration period due to forced acceleration regardless of the stun speed
If CTL (acceleration) (f) shrinks too much, the reversal detection game) (Since the correct rising edge of the PBCTL (acceleration) signal does not come in the section where hl is High, it accelerates too much and returns to the back tracking state again. There was a problem with putting it away.

The present invention solves the above-mentioned conventional problems by accurately performing the reversal from the back tracking reproducing state to the normal tracking reproducing state, and until the normal velocity phase control after the execution reaches the normal state. The purpose is to minimize the time required.

This provides a magnetic recording and reproducing device that does not generate jitter due to back tracking reproduction.

Means for Solving the Problems In order to achieve the above object, the magnetic recording and reproducing apparatus of the present invention outputs a control signal from the first output part based on the speed command signal input to the first input part, and a capstan motor driver that outputs an FC signal from a second output section;
a normal speed phase controller that outputs the speed command to the capstan motor driver from an output section thereof, and the FG multiplier signal that is input to a fourth input section and the control signal that is input to a fifth input section. a 1.5 times speed speed phase controller that outputs the speed command to the capstan motor driver from a fourth output section based on the speed, and the control signal input to a sixth input section and a seventh input. Based on the acceleration start command signal inputted to the section, a fifth output section determines whether the capstan motor driver is controlled by the normal speed phase controller or the 1.5 times speed phase control. an acceleration command device that generates acceleration pulses for switching; a control signal input to an eighth input section; a head switching signal input to a ninth input section; and two of the head switching signals input to a tenth input section. This apparatus is characterized by having a back tracking reproduction discriminator which outputs an acceleration command start signal from an eighth output section based on a 1/2 head switching signal having a double period.

Effect By providing a speed phase controller of 1.5 times speed in the above configuration, when inverting the phase from the back tracking state to the normal tracking state, by controlling the speed phase of the capstan during the acceleration period, It is possible to minimize the pull-in time for normal velocity phase control, and to reliably perform a phase reversal operation from a back tracking state to a normal tracking state.

Embodiment Hereinafter, a magnetic recording and reproducing apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a magnetic recording/reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a timing chart illustrating the operation of the magnetic recording/reproducing apparatus.

Note that configurations similar to those of the prior art are designated by the same reference numerals and detailed description thereof will be omitted.

In FIG. 1, 1 is a capstan motor driver, 2 is a normal speed phase controller, and 5 is a back tracking reproduction discriminator, which has the same structure as the conventional one. , 4 is an acceleration command device, which inputs a control signal 41 and an acceleration command start signal 43.
Only the FG signal is input, and the FG double signal is not input. Also, 3 to 1.
A 5x speed phase controller is provided, which inputs an FG signal 31 and a control signal 32, outputs a speed command signal 33, and controls the capstan motor driver with either a normal speed phase controller or The acceleration pulse 44 is used to switch whether to use the .5x speed phase controller or not.

The operation of the magnetic recording/reproducing apparatus of this embodiment constructed as described above will be described below with reference to FIG. 2.

In FIG. 2, the playback tracking state is determined by PBCT L (
Rising edge a of dl duty ratio (65:35)
It is determined whether the phase of 1 is L level or H level.

In other words, FIG. 2 shows the transition from the back tracking state to the front tracking state.

First, before acceleration starts (before A), the capstan motor driver is controlled by the PBC by a normal speed phase controller.
The rising edge of TL(f) is controlled to be in the center of the servo error signal reference (e). Next, when the back tracking playback discriminator determines back tracking playback, an acceleration pulse is generated at point A, and the control of the capstan motor driver is changed from the normal speed phase controller to the speed phase control at 1.5 times the speed. Switch to vessel. When switching to the 1.5x speed phase control section, a 1.5x servo error signal reference (e)' signal is created in the 1.5x speed phase controller and PBCTL (acceleration) (f) is generated. is controlled so that the rising edge of
(Acceleration) (f) Continue (B, C, D) until three rising edges of the signal occur. Note that the acceleration command device does not require a reversal detection gate as in the conventional example, and stops the acceleration pulse when only three rising edges of PBCTL (acceleration) (f) are input (CD). At point D, the capstan motor driver returns from the 1.5x speed phase control to the normal speed phase control, but the center of the 1.5x speed servo error signal reference (e)' and the servo error signal reference (
Since the center of e) coincides with D, the rising edge of PBCTL (acceleration) (f) will not deviate significantly from the center of the servo error signal reference fe) when switching to normal speed phase control. Therefore, the pull-in time required by normal speed phase control is unnecessary.

Also, at D, al of PBCTLfdl and PBCT
Since a2 of L (acceleration) (f) is the same, a2 will always be in the High section of the phase reference (C),
It is possible to reliably reverse the back tracking playback state to the front tracking state.

Effects of the Invention According to the present invention, prior to performing the reversal process from the back tracking playback state to the front tracking playback state due to acceleration of the capstan, by providing a 1.5x velocity phase controller during the acceleration. By minimizing the pull-in time for speed and phase control after acceleration, the conventional tracking/sinking reversal failure does not occur, eliminating the need for pull-in time after acceleration, and reliably and quickly converting from the back tracking playback state. This allows reversal to the tracking playback state. As a result, it is possible to prevent the occurrence of jitter and tumble due to back tracking, and it is possible to obtain a good reproduced image in the front tracking reproduction state.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a back tracking reproduction discriminator in a magnetic recording/reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a timing chart for explaining the operation of the magnetic recording/reproducing apparatus, and FIG. 3 is a timing chart for explaining the operation of the magnetic recording/reproducing apparatus. A schematic diagram showing a tape recording pattern of a VH3 system VTR, FIG. 4 is a block diagram of a back tracking playback discriminator in a conventional magnetic recording and reproducing device, and FIGS. 5, 6, and 7 show the operation of the conventional device. 2 is a timing chart for explaining. 1...Cab Skun driver, 2...Normal speed phase controller, 3...1.5x speed phase controller, 4...Acceleration Command unit, 5...
・Back tiger/soking playback discriminator.

Claims (1)

[Claims] a capstan motor driver that outputs a control signal from a first output part and an FG signal from a second output part based on a speed command signal input to the first input part; and a second input part. a third input section based on the FG signal input to the third input section and the control signal input to the third input section.
a normal speed/phase controller that outputs the speed command to the capstan motor driver from an output section, the FG signal that is input to a fourth input section, and the control that is input to a fifth input section. a 1.5x speed/phase controller that outputs the speed command to the capstan motor driver from a fourth output section based on the signal; and a seventh From the fifth output section based on the acceleration start command signal input to the input section of
an acceleration command device that generates an acceleration pulse to switch whether the capstan motor driver is controlled by the normal speed/phase controller or the 1.5x speed phase control; The control signal inputted, the head switching signal inputted to the ninth input section, and the first
It is characterized by having a back tracking reproduction discriminator that outputs an acceleration command start signal from an eighth output section based on a 1/2 head switching signal having a cycle twice as long as the head switching input section 0 input section. A magnetic recording and reproducing device.