JPH0253251A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To move a loading (L) post at a constant speed and to draw the phase of a cylinder (S) motor at a high speed by setting a double speed ratio of a capstan (C) motor for each broadcasting method and changing a phase reference signal for the time of loading in response to a recording or reproducing mode. CONSTITUTION:The subject device is provided with a loading means 10 utilizing the C motor as its drive source, a vertical synchronizing signal separating means 3, a recording/reproducing mode discriminating means 12, a phase reference changeover means 5, a broadcasting method discriminating means 16 and a double speed ratio setting means 13 for C motor. Then, a controlling system 6 for C motor speed is set as the recording mode for the broadcasting method at the time of loading, and the double speed ratio of the C motor is set for each broadcasting method. Furthermore, in the case of the recording mode at the time of loading, a vertical synchronizing signal is selected as the phase reference signal for a cylinder phase controlling system 8, and in the case of the reproducing mode, an output signal of a phase reference signal generator 4 is selected. By this method, irrespective of the broadcasting method, the L post is moved at a constant speed by the C motor, and moreover the phase drawing of the S motor can be performed at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic recording/reproducing apparatus having a loading mechanism for winding a magnetic tape around a cylinder.

(Prior Art) Conventionally, magnetic recording and reproducing devices (hereinafter referred to as VTRs) that record and reproduce video signals have a loading mechanism that pulls out a magnetic tape (hereinafter referred to as tape) from a tape cassette and winds it around a cylinder. However, a dedicated motor is used to drive it.

Therefore, it has been difficult to miniaturize the device, and this has been a factor in increasing costs.

To solve this problem, a method was developed in which the loading mechanism was driven by a capstan motor (hereinafter abbreviated as C motor) (for example, Journal of the Japan Society of Mechanical Engineers, Vol. 90, No. 842, P28-38). In this method, a C motor is rotated at a constant speed, a loading post (hereinafter abbreviated as L post) is moved via a loading mechanism, and the tape is wound around a cylinder.

The movement of the L post is controlled by a microcomputer that controls the mechanism of the VTR, and is stopped at a predetermined position to prevent damage to the mechanism. Additionally, the microcomputer counts the travel time of the L post to determine whether the loading operation is normal.

Therefore, in order to drive the loading mechanism with the C motor, it is necessary to move the L post at a constant speed and stop it at a predetermined position.

NTSC by driving the VTR's servo system in recording mode.
(National Television System
The C motor is rotated at a speed five times faster than the standard recording mode of the em Comm1 tee method, and the L post is moved at a constant speed via a transmission mechanism.

In this way, when loading the tape, set the servo system to NTS.
Since it is driven in C mode, for example NTSC or PAL (Phase Alternation
nby Line color television
) method, SECAM (Sequential Co1o
In order to record a PAL video signal using a VTR (hereinafter abbreviated as VTRI) that can be driven in the R&M mode, it is necessary to shift the servo system to the PAL mode after loading.

Furthermore, since the drive is fixed to the servo system during tape loading, 1. For example, in order to reproduce a video signal with a VTRI, the phase reference signal of the cylinder is changed from the vertical synchronization signal to the internal phase reference signal during and after loading. must be switched to.

FIG. 3 is a block diagram of the VTR control system. Reference numeral 1 designates a mode input terminal to which a recording/reproduction mode selection signal is applied, and the recording mode is applied during loading.

2 is a video input terminal; 3 is a vertical synchronization signal separation circuit that separates a vertical synchronization signal from the video signal input from the video signal and divides the frequency by half; and 4 is a phase reference signal generator for the cylinder phase control system in playback mode. , 5 is a phase reference switching circuit that switches between the output signal of the vertical synchronization signal separation circuit 3 and the output signal of the phase reference signal generator 4 based on the input from the mode input terminal 1, and 6 is a phase reference switching circuit based on the input signal from the mode input terminal 1. 8 is a cylinder phase control circuit that controls the phase of the cylinder motor 9 based on the output signal of the phase reference switching circuit 5; 10 is a cylinder phase control circuit that controls the rotation speed of the C motor 7; This is a loading means that is driven through the cylinder and winds the tape around the cylinder.

To move the L post at a constant speed when a recording mode signal is applied to mode input terminal 1 during loading in the recording mode of the VTR.

The servo system is in the NTSC recording mode, and the 1-phase reference switching circuit 5 selects the output signal of the vertical synchronization signal separation circuit 3. At this time, the C motor 7 is rotated by the capstan speed control circuit 6 at a speed five times that of the standard recording mode of the NTSC system, and the loading means 10 moves the L post via the transmission means 11.

Wrap the tape around the cylinder to finish loading. At this time, the phase of the S motor 9 is controlled by the cylinder phase control circuit 8 based on the output signal of the vertical synchronization signal separation circuit 3, but if the video signal is of PAL or SECAM format,
Since the servo system is fixed to the NTSC recording mode, phase control of the S motor 9 is not performed.
In the case of the AL or SECAM method, phase control is performed after loading is completed.

In the case of the VTR playback mode, the loading operation is the same as described above. After loading, mode input terminal 1
The reproduction mode applied from the phase reference switching circuit 5 is applied to the phase reference switching circuit 5, and the output signal of the phase reference signal generator 4 is selected. Therefore, the phase of the S motor 9 is controlled by the output signal of the phase reference signal generator 4.

(Problem to be Solved by the Invention) However, in the above configuration, the servo system is set to the NTSC system during tape loading regardless of the recording/playback mode, so in the playback mode, there is Then, the phase reference signal of the cylinder phase control system must be switched from the vertical synchronization signal of the video signal to the output signal of the phase reference signal generator 4.
Therefore, the phase pull-in characteristic of the S motor 9 deteriorates.

Additionally, if tape loading is performed while a video signal other than the NTSC system is being applied, the servo system is in NTSC mode during that operation, so phase control of the S motor 9 is not performed, and the servo system is switched to its original state after loading. This will be done after switching to the broadcast mode. Therefore, the phase pull-in characteristic of the S motor 9 deteriorates.

Furthermore, it is not enough to simply determine the broadcasting system and set the servo system to that broadcasting system at the time of loading.

Since the C motor 7 is rotated at five times the speed of the standard recording mode of the broadcast system, there is a problem that the moving speed of the L post changes depending on the broadcast system.

In view of the above, the present invention makes it possible to move the L post at a constant speed by the C motor regardless of the broadcasting method even if the servo system is set to the video signal broadcasting method, and further,
An object of the present invention is to provide a magnetic recording/reproducing device that can perform phase pull-in of a C motor at high speed.

(Means for Solving the Problems) The above objects of the present invention are to provide a loading means for winding a magnetic tape around a rotating cylinder using a C motor as a drive source, and a vertical synchronization signal separation means for separating a vertical synchronization signal from a video signal. a recording/playback mode discrimination means; a phase reference switching means for switching the rotational phase reference of the rotary cylinder when winding the magnetic tape based on the discrimination result; and a broadcasting device for discriminating the broadcasting method of the video signal from the output signal thereof. This is achieved by providing a method determining means and a speed ratio setting means for setting the speed ratio of the C motor at the time of loading based on the result of the determination.

(Function) According to the present invention configured as described above, the C motor speed control system is set to the recording mode of the broadcast system at the time of loading, and the double speed ratio of the C motor is set for each broadcast system. The post can be moved at a constant speed, and when loading, the VTR determines whether the recording mode is playback mode, and when it is in recording mode, it selects the vertical synchronization signal separated from the video signal as the phase reference signal for the cylinder phase control system. However, when recording a video signal by selecting the output signal of the phase reference signal generator in playback mode,
When playing back video signals recorded in broadcasting systems other than the NTSC system, the servo system does not switch during the loading operation or even after loading is completed, so the S
Motor phase pull-in can be performed at high speed.

(Example) Hereinafter, the present invention will be explained in detail by way of an example using the drawings.

FIG. 1 is a block diagram showing a VTR control system according to an embodiment of the present invention, in which parts that are the same as those in FIG. 3 or have the same functions are designated by the same reference numerals. The difference from Figure 3 is that the mode input terminal 1
A recording mode or playback mode signal is input to the input mode even though it is in the loading mode. The signal input to the mode input terminal 1 is applied to a mode discrimination circuit 12 that discriminates the recording/playback mode of the servo system, and its outputs 12a, 1
2b are output to the speed ratio setting circuit 13, the cylinder phase control circuit 8, and the phase reference switching circuit 5, respectively.

The vertical synchronization signal separated by the vertical synchronization signal separation circuit 3 is applied to the period detection circuit 14 via the phase reference switching circuit 5, and the output thereof is input to the period comparison circuit 156.
The period detection circuit 14 and the period comparison circuit 15 constitute a broadcast system discrimination circuit 16, and its output signal is sent to the speed ratio setting circuit 13. Single speed ratio setting circuit 1 applied to cylinder phase control circuit 8 and capstan speed control circuit 6
The output of No. 3 is input to the capstan speed control circuit 6.

Note that the phase reference signal generator 4 outputs PAL, SEC, and
Generates AM phase reference.

The operation of the VTR control system configured as described above is as follows:
Since it does not change depending on the SECAM system, the operation of the PAL system will be explained below.

First, in the stop mode, the tape is in the tape cassette and no tape is wound around the cylinder. At this time, both the C motor 7 and the S motor 9 are in a stopped state.

In recording mode, the tape is wound around the cylinder, so the recording mode signal input manually from mode input terminal 1 is
The voltage is applied to the mode discrimination circuit 12, the speed ratio setting circuit 13 and the phase reference switching circuit 5. It is input to the cylinder phase control circuit 8.

At this time, the phase reference switching circuit 5 selects the vertical synchronization signal separated by the vertical synchronization signal separation circuit 3 and applies it to the broadcast system discrimination circuit 16. In addition, the cylinder phase control circuit 8
enters the recording mode, and performs phase control using the separated vertical synchronization signal as a phase reference signal for the S motor 9. At this time, the broadcasting system is determined by the broadcasting system discrimination circuit based on the vertical synchronization signal from the vertical synchronization signal separation circuit 3. 16 makes the determination.

This broadcast system discrimination circuit 16 measures the time of two cycles of the vertical synchronization signal applied by the nine-cycle detection circuit 14, and applies the period data T to the cycle comparison circuit 15. The period comparison circuit 15 receives two periods of reference period data T, , T, of each vertical synchronization signal of the NTSC system and the PAL system.
Threshold value T? for broadcasting system discrimination, which is the central value of T? is provided with data, and the input cycle data T is set as a threshold value T.
5 data, the cycle data T is the threshold value T. When it is larger than the data, it is determined that the PAL broadcasting system is 1. When the opposite is the case, it is determined as the NTSC system.

In other words, the threshold T0 for broadcasting system discrimination is expressed by the following equation (1),
The discrimination conditions are expressed by equations (2) and (3).

-(TIl+TP)1.11.170911. (1)7
th −2 Here, Tn=33.3+ms, Tp=40+ms.

The conditions for PAL system are T>T, ・・・・・・(
2) The conditions for the NTSC system are TNTa,...
3) As described above, the broadcasting system mode determined by the broadcasting system determining circuit 16 is applied to the cylinder phase control circuit 8, the double speed ratio setting circuit 13, and the capstan speed control circuit 6.

The double speed ratio setting circuit 13 is configured so that the applied broadcast system mode is N.
When using the TSC system, a command to rotate the C motor 7 at five times the speed of the NTSC standard recording mode is output to the capstan speed control circuit 6, and when using the PAL system, the C motor 7 is output to the PAL system.
A command to rotate the capstan at seven times the speed of the standard recording mode is output to the capstan speed control circuit 6. The tape speed for each of the NTSC and PAL systems is 33.35 m/see,
23.39 mm/see, so by setting the speed of the C motor 7 to 5x speed in the NTSC system and 7x speed in the PAL system, the C motor can be rotated at almost the same number of rotations. At this time, the rotational speed N of the C motor 7 is expressed by equation (4).

N = 33.35 x 5 /φ clause 23.39 x 7
/φ... (4) However, φ is the capstan shaft diameter.

The capstan speed control circuit 6 receives the double speed ratio setting command output from the double speed ratio setting circuit 13 and the broadcasting system discrimination circuit 16.
The C motor 7 is rotated at a constant speed so as to keep the moving speed of the L post constant based on the broadcast system determination result input from the controller. Then, the L boss pulls out the tape from the tape cassette and winds it around the cylinder.

On the other hand, when playing back a tape in the case of the PAL system, when the VTR enters the playback mode, the tape is wound around a cylinder, so a playback mode signal is input to the mode determination circuit 12 from the mode input terminal 1. The mode discrimination circuit 12 outputs a recording mode signal to the double speed ratio setting circuit 13 even though the VTR is in the reproduction mode.

A reproduction mode signal is output to the phase reference switching circuit 5 and the cylinder phase control circuit 8.

When the reproduction mode signal is input, the phase reference switching circuit 5 selects the PAL phase reference signal of the output signal of the phase reference signal generator 4, which is input to the broadcasting system discrimination circuit 16 and the cylinder phase control circuit 8. .

The broadcast system determination circuit 16 determines the broadcast system as PAL, similarly to when the VTR is in the recording mode described above, and sends the broadcast system determination result to the capstan speed control circuit 69, double speed ratio setting circuit 13, and cylinder phase control circuit 8. Output.

The cylinder phase control circuit 8 enters the regeneration mode and performs phase control using the output signal of the phase reference signal generator 4 as a phase reference signal for the S motor 9. The operation of the capstan speed control system is the same as that described above when the VTR is in the recording mode, so a description thereof will be omitted.

As described above, in both the NTSC and PAL broadcasting systems, by switching the speed ratio of the C motor 7 using the speed ratio setting circuit 13 during loading, it is possible to make the rotational speed of the C motor 7 almost the same in both systems. I can,
Thereby, the moving speed of the L post driven via the transmission means 11 becomes the same, and it becomes possible to move the L post at a constant speed regardless of the broadcasting system.

FIG. 2 is a signal waveform diagram showing the operation of the cylinder phase control system.

a, b, c represent NTSC, d, e, f represent PAL, and g+l'l+l represent the respective phase-controlled operating states when the PAL broadcast was recorded. a and d are the output signal waveforms of the vertical synchronizing signal separation circuit 3, and g is the output signal waveform of the phase reference signal generator 4, which serve as reference signals for the cylinder phase control system. Moreover, b, e, h are the above-mentioned an
This is a trapezoidal wave signal created by the cylinder phase control circuit 8 based on the reference signal of d+g. c, f, i are cylinder head switch (hereinafter referred to as H, W) signal waveforms, b
The trailing edge of the I(□ signal is located at the center of , e, and h. This is the waveform resulting from the phase control performed by the cylinder phase control circuit 8.

In the recording mode of the VTR, in order to move the L post at a constant speed during loading, if the servo system is fixed to the NTSC recording mode, when the broadcasting format of the video signal applied from the video input terminal 2 is PA L, S motor 9
The phase reference signal of is the signal waveform of d, and the trapezoidal wave signal created by the cylinder phase control circuit 8 is as shown in b.
Phase control of the S motor 9 becomes impossible.

As a result, after loading is completed, the cylinder phase control system must be shifted to PAL mode and phase pull-in must be performed, so it takes a long time until phase lock is achieved.

In addition, in the playback mode of the VTR, if the servo system is fixed to the NTSC recording mode in order to move the L post at a constant speed, the signal applied from the video input terminal 2 will be recorded on the PAL video signal or tape. When the video signal is a video signal, the phase reference signal of the S motor 9 has a waveform of d, and the trapezoidal waveform signal of the cylinder phase control circuit 8 has a waveform of b, so that the phase of the S motor 9 cannot be controlled.

As a result, after loading is completed, the phase reference of the S motor 9 is switched to the internal phase reference signal, and the cylinder phase control system is changed to P.
Transition to AL mode ° [Phase pull-in will be performed,
It takes time to phase lock.

However, in this embodiment, the servo system's NTSC, P
The AL mode setting and recording/playback mode are determined at the time of loading, so whether the NTSC or PAL
In the case of recording a PAL video signal and in the case of reproducing a tape on which a PAL video signal is recorded, the relationship between the phase reference signal of the S motor 9 and the trapezoidal wave signal created by the cylinder phase control circuit 8 is (a , bL (d, eL (g, h
), the phase reference signal does not change during and after the loading operation, and therefore the phase of the S motor 9 is pulled in at high speed. Moreover, the moving speed of the L boss is set to either NTSC or PAL system on the servo system.
Since the C motor 7 can be rotated at a substantially constant speed by the double speed ratio setting circuit 13 and the capstan speed control circuit 6, the L post can be moved at substantially the same speed regardless of the broadcast system.

(Effects of the Invention) As is clear from the detailed explanation above, the present invention allows the speed ratio of the C motor to be adjusted for each broadcast system even if the capstan speed control system is set to the recording mode of the broadcast system at the time of loading. By setting it to , the L post can be moved at a constant speed, and the phase reference signal at the time of loading can be switched according to the recording/playback mode of the VTR by the mode discrimination means and the phase switching means. Also, when recording FAI video signals or playing back tapes of video signals recorded in the PAL format, the phase pull-in of the S motor becomes faster, so you can get great results by implementing it. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a VTR control system in an embodiment of the present invention, FIG. 2 is a waveform diagram explaining the operation of FIG. 1,
FIG. 3 is a block diagram showing a conventional VTR control system. 1...Mode input terminal, 2...Video input terminal, 3
... Vertical synchronization signal separation circuit, 4 ... Phase reference signal generator, 5 ... Phase reference switching circuit, 6 ... Capstan speed control circuit, 7 ... Capstan motor (abbreviated as C motor) ), 891. Cylinder phase control circuit, 9... cylinder motor (abbreviated as S motor),
10...Loading means, 11...Transmission means,
12...Mode discrimination circuit, 13...Double speed ratio setting circuit, 14...Period detection circuit, 15...Period comparison circuit, 16...Broadcast system discrimination circuit. Patent applicant: Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] A loading means for winding a magnetic tape around a rotating cylinder using a capstan motor as a drive source, a vertical synchronizing signal separating means for separating a vertical synchronizing signal from a video signal, a recording/playback mode determining means, and the above-mentioned method based on the determination result. A phase reference switching means for switching the rotational phase reference of the rotary cylinder when winding the magnetic tape, a broadcasting method determining means for determining the broadcasting method of the video signal based on the output signal thereof, and a double speed of the capstan motor at the time of loading based on the determination result. 1. A magnetic recording and reproducing device comprising: a speed ratio setting means for setting a speed ratio.