JPS6273883A - Magnetic video recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain recording/reproduction of the 1st video signal and the 2nd video signal equivalent to an n multiple of the field period of the 1st video signal by providing a reproduction control signal period discrimination means for applying control to give the same tape running speed and cylinder number of revolutions as those at recording. CONSTITUTION:An output of a CTL period discrimination circuit 24 goes to a low level when an output pulse frequency of a CTL signal reproducing amplifier 23 is 60Hz and the output of the circuit 24 goes to a high level when the pulse frequency is 30Hz, and in the high level, switches 10, 25 are changed over to the position shown in a figure and in the low level, the switches are changed over to the opposite direction. On the other hand, a switch 25 selects either an output of a 60Hz reference signal generating circuit 26 or an output being frequency division of a 1/2 frequency division circuit 27 and the result is sent to a phase synchronizing circuit 16. Thus, the cylinder, in the same way as the recording, is driven at a double speed at 120 fields/sec in comparison with the speed of 60 fields/sec. Thus, the 1st video signal and the 2nd video signal whose field period is an n multiple of the field period of the 1st video signal are recorded and reproduced.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a magnetic recording and reproducing device. Especially the first video signal. The present invention relates to a magnetic recording and reproducing apparatus (hereinafter referred to as a VTR) which records and reproduces a second video signal whose field period is one field period of the first video signal.

[Background of the invention]

In home VTR. As is well known, a two-head helical scan method is used, and this is not the case for NTSC television signals (hereinafter referred to as TV signals) that scan at 60 fields/second. Equipped with a video hand [7 rotating cylinders that rotate at 30 rps. A method is used in which each field is modulated by F1 and a video signal is recorded on each recording track.

recently. To significantly reduce unnatural motion in video images. The number of scanning lines is the same as the NTSC system (525 lines/
frame), double the horizontal scanning frequency (3 1.5 K
Hz) and scanning at 120 fields/sec has been proposed.

in this case. Generally, the scanning period of both the television camera and the receiver. In other words, it is conceivable that the system be configured to be compatible with 60 fields/sec and 120 fields/sec, and the user can select and use either mode.

on the other hand. In the home VTR mentioned above. Naturally, it is necessary to be able to record and reproduce video signals of both scanning periods using the same deck, but in this case the following problems arise.

First, 120 fields/second is 60 fields/second.
Compared to the second one. The video signal frequency band is twice as large. During recording, it is necessary to determine which cycle is being used and change the tape speed and cylinder rotation speed. Also, when playing. Automatically determines which period of the signal is being recorded. Similarly, the tape speed and cylinder rotation speed must be changed.

Conventional. As disclosed in US Pat. No. 4,044,389, video signals according to the NTSC system are recorded at different tape speeds of 1v (recording time mode).

When playing. A method has been proposed to automatically determine the tape speed at the time of recording. As mentioned above, there is no example of recording signals with different field periods on the same VTR deck. Therefore, there has been no proposal for a method for determining the field period.

[Purpose of the invention]

The present invention has been made to eliminate the above-mentioned drawbacks. Its purpose is the first video signal.

A VTR capable of recording and reproducing both a second video signal whose field period is one times that of the first video signal. Our goal is to provide the following.

[Summary of the invention]

In order to achieve the above object, the present invention. Tape speed. The feature is that the cylinder rotational speed and the period of the control signal are controlled as follows.

First, when recording. Separates the vertical synchronization signal from the video signal to be recorded and determines its period. For example, if the period is 60EIz like an NTSC video signal. Conventional VT
Similarly to R, rotate the cylinder at a speed of 30 rps. The tape is run at a standard speed according to VTR standards.

on the other hand. Double scanning (from τ, when the vertical synchronization signal has a period of 120 Hz, the cylinder rotates at a speed of 60 rps,
The tape is run at twice the standard speed.

Furthermore, the carrier frequency of the FM modulated signal to be recorded is also approximately doubled. In this way, the scanning period is doubled and B'
Even when the XL image signal frequency band is twice as large, it is possible to record the video signal in the necessary band with approximately the same recording wavelength and track pitch as in the past.

On the other hand, the control signal for video tracking control (hereinafter referred to as CTL signal) is set to 1.5 so that it is recorded at the same 30Hz cycle regardless of the scanning cycle. C during playback
Automatic discrimination is possible based on the reproduction cycle of the TL signal.

During playback, 1 For example, if the tape speed is run at twice the standard speed and the CTL signal is played back, 1 For example, the video cycle is 60H.
The playback cycle of the CTL signal corresponding to z is 60&, and the playback cycle of the CTL signal corresponding to the video cycle of 120flz is 30i(z. In this way, the CTL signal is recorded and replayed at a constant cycle regardless of the vertical scanning cycle. By doing this, it becomes possible to automatically determine the M production mode. By configuring as described above, the same VTR as the conventional one can be used.
Although it uses a deck, it can handle video signals with either 60b or 120flz scanning cycles, and can perform automatic discrimination during recording and playback.

[Embodiments of the invention]

8 The present invention will be described in detail below with reference to the drawings. Here, we are dealing with a video signal of 60 fields/second based on the NTSC system and a video signal of twice that, 120 fields/second. An example will be described in which both are recorded and reproduced at the same track pitch.

Figure 1 is a circuit block diagram explaining the operation during recording, 82
First, the figure is a circuit block diagram explaining the operation during playback. Referring to FIG. 1, the operation during recording will be explained.

In FIG. 1, a vertical synchronization separation circuit 3 is connected to the output side of the synchronization separation circuit 2 connected to the input terminal l, and a period determination circuit 4, 1/4 is connected to the output side of the vertical synchronization separation circuit 3.
It is connected to a frequency divider circuit 5 and a 1/2 frequency divider circuit 6.

The output side of the cycle discrimination circuit 4 includes a tape running speed control means I and a control signal recording means.

The output side of the 1/4 frequency dividing circuit 5 is connected to the control signal recording means 2, and the 1/4 frequency dividing circuit 5 is connected to the output terminal 22.
The output side of the frequency divider circuit 6 is a control signal recording means ■,
Connected to cylinder rotation speed control means ■.

The tape running speed control means 1 includes a capstan 11 coupled to a capstan motor 12.

A changeover switch 10 that switches between the output of the gearbox 11 and the output of the 1/2 frequency dividing circuit 13 that divides the output into 1/2 according to the output state of the period discrimination circuit 4, and a frequency-voltage connected to the changeover switch 10. (hereinafter referred to as F-V) converter 14 and a motor drive circuit 1 that controls the capstan motor 12 according to the output of this F-■ converter 14.
It consists of 5.

-H control signal recording stage ■ is 1 cycle discrimination circuit 4
depending on the output state. A changeover switch 7 for switching between the 1/4 frequency divider circuit 5 and the 1/2 frequency divider circuit 6, and this changeover switch 7
A control signal (hereinafter referred to as CTL Shintan) connected to an IF recording amplifier 8 is constructed, and the output of the CTI and Shinyo recording amplifier 8 is recorded on the recording tape 21 by the head 9. The control means ■ is cylinder 1) cylinder motor 1
8, a cylinder rotation detection circuit 20 for shaping the tack signal from the tack generation circuit 19, and a skewer of the cylinder rotation detection circuit 20.
a phase synchronization circuit 16 which inputs the output of the /2 frequency divider circuit 6;

According to the output of this phase synchronized circuit 16, the cylinder motor 1
8 and a motor drive circuit 17' for controlling the motor.

Next, the recording operation will be explained.

The video signal inputted from the input terminal 1 is applied to the sync separation circuit 2 composed of a comparator.

The vertical synchronization signal and horizontal synchronization signal are separated.

Furthermore, only the vertical synchronization signal is selected by a vertical synchronization separation circuit 3 composed of a low-pass filter and a comparator. The vertical synchronization signal is 6011z depending on the input video signal.
Or with a 120FIz pulse signal.

For example, a vertical period discrimination circuit 4 composed of a counter circuit
sent to. For example, if the person's caballus has a cycle of 60Hz, the output of the cycle discrimination circuit 4 is low level, 1
If the period is 2011z, a control signal of NO level is obtained and drives the changeover switch 7.10. This changeover switch 7.10 is connected in the direction shown when this control signal is at a high level, and in the opposite direction when it is at a low level.

Further, the output of the vertical synchronization separation circuit 3 is also guided to a 1z4 frequency divider circuit 5 and a 1z2 frequency divider circuit 6. 1z4 frequency divider circuit 5
The output is t5FIz or 30 depending on the input video signal.
[This is a 1z pulse signal, and the output of the 1z2 frequency divider circuit 6 is a 30h or 60Hz pulse signal.

As mentioned above, the switch 7 switches the input video signal to 12
At 0 fields/sec in the direction shown.

At 60 fields/sec, it is connected in the opposite direction, so
CTL signal recording amplifier8. The CTL signal recorded on the magnetic tape 21 via the head 9 always has a period of 30 tlz.

Further, the output of the 1/2 frequency divider circuit 6 is applied to the phase synchronization circuit 16. This phase synchronized circuit 16 includes a cylinder motor 18
The tack signal from the tack generation circuit 19 coupled to the
A signal shaped by the cylinder rotation detection circuit 20 is also added,
After comparing both phases, a control voltage is sent to the motor drive circuit 17, and the cylinder motor 18 is rotated at a specified speed and phase. With this configuration, when the input video signal is 120 fields/second, the cylinder rotation speed can be doubled compared to when the input video signal is 60 fields/second.

In the tape running speed control means, the output of the capstan 11 coupled to the capstan motor 12 and the output obtained by frequency-dividing this output by the 1z2 frequency dividing circuit 13 are connected to the switch 1.
being led to 0. The output of the switch 10 is applied to the F-V converter 14 and converted into a control voltage according to one frequency.

Controlling the motor drive circuit 15, the capstan motor 1
2 at a specified speed and phase.

The switch 10 performs the switching operation described above.

If the input video signal is 120 fields/second, the tape running speed can be doubled compared to when the input video signal is 60 fields/second.

In addition, the output of the rabbit's vertical period discrimination circuit 4 is as follows.

The signal is sent from the output terminal 22 to a video signal circuit (not shown), and is used to change the FM carrier frequency for recording and to change the characteristics of each part of the 1M circuit.

Next, the operation during reproduction will be explained with reference to FIG. 2, in which the same parts as in FIG. 1 are given the same reference numerals.

The reproduced CTL signal period determining means (2) reproduced by the head 9 includes a CTL signal reproducing amplifier 23 and a CTL period determining circuit 24.
The output side of this CTL cycle discrimination circuit 24 is connected to the changeover switches 10 1 , 25 2 and the output terminal 28 .

The changeover switch 25 switches between the output of the 60tlz reference signal generation circuit 26 and the 1z2 frequency divider circuit 27 that divides the output into 1/2 depending on the output state of the CTL cycle determination circuit 24.
The configuration is such that the output is switched and supplied to the phase synchronization circuit 16 of the cylinder rotation speed control means (2).

At startup, it is assumed that the changeover switches 10 and 25 are connected in the direction shown in the figure, ie, in the direction for recording and reproducing a 20 field/second video signal.

When playing the magnetic tape 21 under these conditions, the magnetic tape 21
The signal recorded in 1 is 60 fields/second or 120 fields/second.
Fields per second
The output pulses of each have a period of 6 (lHz or 30 Hz).

CTL consisting of a configuration similar to the vertical period discrimination circuit 4 of the rabbit
The output of the period discrimination circuit 24 is low level when the output pulse of the CTL signal regeneration amplifier 23 is 6011 z, 30 Hz.
In this case, configure it so that it is at a high level, and this is it!
- In the case of high level, the switch 10.25 remains connected in the direction shown in the figure, but in the case of low level, it switches to the opposite direction.

Therefore, the capstan motor 12 operates in the same way as during recording.

When a signal of 120 fields/second is recorded,
It can rotate at twice the speed compared to 60 fields/sec.

On the other hand, the switch 25 selects either the output of the 60b reference signal generation circuit 26 or the output divided by the 1/2 frequency divider circuit 27 and sends it to the 1-phase synchronization circuit 16. For this reason, the cylinder is also open during recording. At 120 fields/second, it is twice as fast as 60 fields/second (60rps).
It rotates at a speed of 'H.

Note that the output of the CTL cycle discrimination circuit 24 is output from the output terminal 2.
The signal 1 is sent to 8 and used for switching the characteristics of a video signal circuit (not shown).

In the above explanation, the configuration and operation have been explained separately for recording and reproducing as shown in FIGS. 1 and 2, but many parts of recording and reproducing can be shared. Therefore, as shown in FIG. 3, the overall configuration is such that recording/reproducing mode changeover switches Lot, 102, 103 are added to connect in the direction shown in the figure during recording and in the opposite direction during reproduction.

Also, the NTSC system (60 fields/second).

Although the explanation has been given using a video signal with twice the period as an example, the invention is not limited to this, and for example, the PAL method (
50 fields/sec) and a video signal with a period twice that period can be similarly applied.

At this time, the CTL signal has a period of 25111z. Also.

Although it is limited to 2 times, it can also be applied to video signals with double periods.

〔Effect of the invention〕

As is clear from the above description, one aspect of the present invention is as follows. When a second video signal whose field period is four times that of the first video signal is input, the cylinder rotation speed and tape running speed are automatically increased to nine times that of when the first video signal is input. , and all video signals are recorded with the same recording wavelength and track pitch.

In either case, record the control signal with the same period,
During playback, the cycle of the reproduced control signal is determined and the same cylinder rotation speed and tape running speed as during recording are provided. This has the effect of providing a VTR capable of recording and reproducing a second video signal that is nine times the field period of the signal.

[Brief explanation of drawings]

1. P is a circuit block diagram explaining the operation during recording, FIG. 2 is a circuit block diagram explaining the operation during reproduction, and FIG. 3 is a circuit block diagram showing a VTR according to an embodiment of the present invention. ■...Tape running speed control means. ■...Control signal recording means. III... Cylinder rotation speed control@means. ■...Reproduction CTL signal period determination means. 4... Period determination means. 7'1

Claims (1)

[Claims] 1. During recording, a period determining means for determining the vertical synchronization signal period of an input video signal, and a second video signal whose field period is one times that of the first video signal. Tape running speed control means and cylinder rotational speed control that, when inputted, provide a tape running speed and cylinder rotational speed that are n times higher than when the first video signal is inputted, based on the output of the period determination means. control signal recording means for outputting a control signal of the same cycle and recording it on the running tape when either the first video signal or the second video signal is input; a reproduction control that determines the cycle of the control signal and controls the tape running speed control means and the cylinder rotation speed control means to give the same tape running speed and cylinder rotation speed as during recording based on this discrimination signal; What is claimed is: 1. A magnetic recording and reproducing device comprising: signal cycle determining means. 2. The first video signal is 60 fields/second, the second video signal is 120 fields/second, and the control signal is 30 fields/second.
Hz.
) The magnetic recording and reproducing device described in item 2. 3. The tape running speed control means uses a capstan coupled to a capstan motor, the output of this capstan, and the output of a 1/2 frequency divider circuit that divides the output into 1/2 as an output of a period determination circuit. The control signal recording means is composed of a changeover switch that changes depending on the state, a frequency-voltage converter connected to the changeover switch, and a motor drive circuit that controls the capstan motor according to the output of the frequency-voltage converter. However, there is a changeover switch that switches between a 1/4 frequency division circuit and a 1/2 frequency division circuit depending on the output state of the period discrimination circuit, a control signal recording amplifier connected to this changeover switch, and a magnetic field that controls the output of this control signal recording amplifier. The cylinder rotation speed control means comprises a head for recording on a tape, a tack generation circuit coupled to a cylinder motor, and a cylinder rotation detection circuit for shaping a tack signal from the tack generation circuit;
a phase synchronization circuit that inputs the output of the cylinder rotation detection circuit and the output of a 1/2 frequency divider circuit that frequency-divides the vertical synchronization signal;
and a motor drive circuit that controls the cylinder motor according to the output of the phase synchronized circuit, and the regeneration control signal period determination means is comprised of a control signal regeneration amplifier and a control signal period determination circuit. A magnetic recording and reproducing apparatus according to claim (1).