JPH04144385A - Vtr - Google Patents

Abstract

PURPOSE:To inhibit illegal copy in the high picture quality mode and to prevent occurrence of malfunction by validating a copy guard signal under the condition that the state is in the recording state of the high picture quality mode when the video signal with the copy guard signal added thereto is applied to the VTR. CONSTITUTION:A display signal representing that a cassette from a holder to which a tape cassette 16 is placed is able to record a high picture quality signal and a display signal or the like representing a carrier servo of a magnetic tape 17 from a mechanism servo circuit 20 to be locked are fed to an AND circuit 24. Then the signals are fed to an AGC pulse generating circuit 19. Thus, the tape cassette 16 is able to record a signal with high picture quality and the high picture quality recording mode is selected as the recording mode and an external input terminal 11 is selected and when the carrier servo of the magnetic tape 17 is locked, a copy guard signal is validated. Thus, the disturbance on the reproduction not aiming at copying by the copy guard signal is avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a VTR having a standard mode and a high-quality mode, such as an 8 mm VTR.

[Summary of the invention]

The present invention relates to a VTR, and when a video signal to which a copy guard signal is added is supplied, the copy guard signal is made valid on the condition that the recording state is in a high image quality mode. The system prohibits illegal copying in high-resolution mode, allows personal copies to be made at home, etc., and prevents malfunctions due to erroneous detection of copy guard signals. It is.

[Conventional technology]

For example, in an 8 mm VTR, video signals are recorded and reproduced in a standard mode and a high-quality mode (Hi8), which has at least a higher resolution than the standard mode.

On the other hand, for the purpose of protecting the copyright of video tape software, a special signal is inserted into a part of the video signal recorded on the video tape, and this signal is played back to allow other VT
Video tape software is being distributed that makes it impossible to maintain the quality of the recording signal at all when attempting to record in R.

Reference: Japanese Patent Application Laid-Open No. 61-288582 [Problem to be Solved by the Invention] However, when such a so-called copy guard is adopted, a VTR designed to respond to the above-mentioned signals
For example, if you try to edit a personal recorded video signal taken with a video camera, the so-called guard hand noise that occurs when searching for an editing point by fast forwarding or rewinding playback will cause the above-mentioned copy guard noise. This may result in significant deterioration of the image displayed on the monitor receiver, which may hinder the search for the editing point.

Alternatively, if you use a VTR as mentioned above as a final terminal to connect to a monitor receiver, recording (copying)
Even though the VTR is not intended for this purpose, the signal supplied to the monitor receiver through the recording system of the VTR may deteriorate, making it impossible to view the video. Therefore, there has been a problem that the uses of such a VTR are limited.

However, in so-called standard mode recording and reproduction, the quality of the video signal is not necessarily sufficient, and in particular, the image quality of the video signal copied in this standard mode has deteriorated considerably. Therefore, there is an idea that there is no need to prohibit even such degraded copies. This is because copying is legally permitted for personal use at home.

This application was made in view of these points, and it is a VTR that can consistently perform good recording and playback with a simple configuration.
It provides:

[Means to solve the problem]

The present invention provides a VTR having a standard mode and a high-quality mode with at least a higher resolution than the standard mode, in which a video signal to which a copy protection signal is added is supplied (input terminal (11)). The copy guard signal is enabled (AGC amplifier (19)) under the condition that the recording state is in the high image quality mode (AND circuit (24)). It's a VTR.

[Effect]

According to this, the copy guard signal is enabled only when recording in high image quality mode, so playback that is not intended for copying will not be interfered with by the copy guard signal, and the high image quality Illegal copying in this mode can be prohibited in the same way as before, and good recording and playback can always be performed with a simple configuration.

〔Example〕

In Figure 1, a video signal from another VTR (1) or video camera (2) is input to the external input terminal (
11). The video signal supplied to this input terminal (11) is supplied to the video processing circuit (13) via the AGC amplifier (12), and after being subjected to predetermined processing, it is sent to the rotating head via the recording amplifier (14). (15) and is recorded on a magnetic tape (17) fed out from a tape force center (1G). Note that the configuration of other video signal recording systems such as a built-in tuner is well known and will therefore be omitted.

Furthermore, the video signal supplied to the input terminal (11) is supplied to a sync separation circuit (18), and the separated sync signal is supplied to a video processing circuit (13), and this separated sync signal will be described later. AGC pulse generation circuit (
19). The generated AGC pulse is then supplied to the AGC amplifier (12).

In addition, the synchronization signal separated by the synchronization separation circuit (18) is
Supplied to a mechanism servo circuit (20) that performs drive servo of mechanisms such as a rotary head (15) and a magnetic tape (17),
The rotating head (15) is controlled by this mechanical servo circuit (20).
), capstan (21), etc. are driven.

The display signal indicating whether there is a tape cassette) (
The mechanical servo circuit (20) is supplied from the holder (not shown) on which the motor (16) is placed.

Furthermore, a system control circuit (22) is provided,
Operation signals from the operation panel (23) are supplied to this system control circuit (22). Also, from the holder in which tape strength is set (16) is placed, a signal indicating whether the cassette has been subjected to accidental erasure prevention processing and a signal indicating whether the cassette is capable of high-quality recording are sent to the system control. It is supplied to the circuit (22). The mechanism servo circuit (20) is controlled in response to these signals, and the video processing circuit (13) is controlled in response to these signals.
The processing details (recording mode) are set.

Furthermore, in this device, a tape force set (16
) from the boulder on which cassettes 1 to 1 are placed are capable of high-quality recording. A display signal indicating that the input terminal (11) has been selected and a mechanism servo circuit (20
) is supplied to the AND circuit (24), indicating that the transfer servo for the magnetic tape (17) is locked;
A signal from this AND circuit (24) is supplied to an AGC pulse generation circuit (19).

This allows the device to apply a tape force of 7-1-(1
6) is capable of high-quality recording, the copy guard signal is enabled when high-quality recording and external input terminal (11) are selected as the recording mode, and the magnetic tape (17) transfer servo is locked. Control is performed so that the

That is, for example, FIG. 2A shows an example of the copy guard signal shown in the above-mentioned document.

This signal is provided, for example, over seven consecutive horizontal scanning periods after the equalization pulse within the vertical blanking period, and one horizontal scanning period is shown in the figure. In this signal, a pedestal level period of the same length is provided following a horizontal synchronization pulse of 4.7 (7zsec). Then - of 2.0 (μ5ec)
A 40% synchronization level period followed by a 100% white level signal is provided for a period of 3.7 (μ5ec), followed by a pedestal level period of 1.8 (μ5ec), and this signal is repeated five times.

For example, in a conventional 8mm VTR, the fall of the synchronization level signal is detected as shown in Figure B, and from a position 6.5 (μ5ec) after this, 2.0 as shown in Figure C. (μ5ec) AGC pulses were generated. As a result, normal AGC is achieved by detecting the peak value of the video signal during each AGC pulse period and performing AGC so that the level becomes the pedestal level.
GC operation can be performed.

On the other hand, as shown in the same figure, a rising edge of the synchronization level signal is detected, and from a position 6.5 (μ5ec) after this, an AGC of 2.0 (μ5ec) is detected as shown in E of the same figure.
When a pulse is generated, the peak value of the video signal during each AGC pulse period becomes the 100% white level, and by performing AGC so that this level becomes the pedestal level, the original video signal level is almost reduced. The brightness becomes equal to the pedestal level, and the brightness is extremely reduced, making it unwatchable.

Therefore, in the above device, the AGC pulse generation circuit (
19), the fall of the synchronization level signal is normally detected to ensure normal AGC operation, and
When the signal from Anne 1' circuit (24) is supplied,
By detecting the rise of the synchronization level signal, the copy guard signal is validated and illegal copying can be prohibited.

In this way, according to the above-mentioned device, the copy guard signal is enabled only when recording in high-quality mode.
Playback that is not intended for copying will not be interfered with by copy guard signals, and illegal copying in high-quality mode can be prohibited as before, making it possible to always achieve good recording and playback with a simple configuration. It is something that can be done.

That is, in the above device, for example, an AGC amplifier (1
Even if the output of 2) is taken out to the output terminal (25), guard band noise during fast forward/rewind playback may be mistakenly detected as a copy guard signal when the recording state is not in high quality mode. This prevents the signal supplied to the monitor receiver from being degraded even though it is not intended for recording (copying). Therefore, even when collecting a collection of songs by supplying personal recorded video signals taken with a video camera, or when using a VTR as a terminal for connecting to a monitor receiver, the VTR can be used.
can be used effectively.

In addition, in the above embodiment, the case where the signal shown in the above-mentioned document is used as the copy guard signal was explained, but even if other signals are used as the copy guard signal, the same may be used. The above-described apparatus can be implemented by providing means for controlling validity/invalidity of the copy guard signal.

[Effects of the Invention] According to the present invention, since the copy guard signal is enabled only in the recording state of high image quality mode, playback, etc. not intended for copying will not be interfered with by the copy guard signal. In addition, illegal copying in high-quality mode can be prohibited as before, and it is now possible to always perform good recording and playback with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an example of a television receiver according to the present invention, and FIG. 2 is a waveform diagram for explaining the same. (1) is another VTR1 (2) is a video camera, (11
) is the input terminal, (12) is the AGC amplifier, (13) is the video processing circuit, (14) is the recording amplifier, (15) is the rotating head, (16) is the tape cassette, (17) is the magnetic tape, (18) is the ) is the synchronous separation circuit, (19) is the AGC pulse generation circuit, (20) is the mechanical servo circuit, (21)
(22) is the system control circuit, (23) is the operation panel, (24) is the AND circuit, (2
5) is an output terminal.

Claims (1)

[Claims] In a VTR having a standard mode and at least a high-quality mode with higher resolution than the standard mode, when a video signal to which a copy protection signal is added is supplied, A VTR characterized in that the copy guard signal is enabled on condition that the recording state is in the high image quality mode.