JPS58199459A - Video reproduction system - Google Patents

Abstract

PURPOSE:To prevent a video recording medium from being used easily, by providing mode switches corresponding to each mode function of a video reproducing device, and putting the reproducing device in operation ohly when the mode function coincides with a key code. CONSTITUTION:Key code signals from output terminals (a)-(d) of a shift register 14 are applied to one-side terminals of exclusive OR circuits 15-18. Then, mode signals (a')-(d') from a mode switch 2 are applied to the other-side terminals. Consequently, only when the key code signals (a)-(d) coincide with the mode signals (a')-(d'), an AND circuit 19 outputs a high-level signal. This output signal is applied to a terminal S of a flip-flop, whose contents are set. The flip-flop 20 outputs a high-level signal to an analog switch 10, and a video signal from a buffer amplifier 9 is outputted from a terminal T6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a video playback system configured to perform a playback operation only when specific conditions are met.・Video tape recorders (VTRs) and other video playback devices have become widespread and can be easily used in every home, but the fact that they can be easily operated by anyone can sometimes be a disadvantage.
There may be cases where

For example, a software playback specialized for VTRs is on sale, but since the contents include content that is not suitable for educational purposes, it is problematic for children to be able to play and earn money more easily than by setting up a VTRK. . Even if you hide such soft tapes from children's eyes, there are limits, and even if you set the tape into a playback device, it is desirable that the playback device will not operate with simple operations. It can be covered. □ Furthermore, if confidential content is recorded, it is desirable that the content cannot be easily reproduced by others.゛The present invention has been made in response to the above-mentioned requests, and a video playback device is provided with separate mode functions, and a key code corresponding to the □Jouhi mode function is provided for recording media such as cheese. It is an object of the present invention to provide a video playback system configured such that when a recording medium is set in a video playback device and the mode function and key code match, the video playback device operates. There are wooden ones. Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a video playback device, for example, VTl'L, used in a video playback system according to an embodiment of the present invention.
A mode switch 2 for each mode function is provided on the panel surface of R1 along with many other operation switches. As for the mode function, for example, it is designed to have uses such as for adults and children.

Further, for a recording medium such as a tape, a key code corresponding to each mode of the above-mentioned mode functions is inserted in step 5-j.

Figure 2 shows an example of inserting a key code into a part of a television signal (video signal). Several bits of key codes Kl and 2 are inserted into the blanking portions. Note that Al and A2 indicate an equivalent pulse section, and B indicates a vertical synchronizing pulse section.

FIG. 3 is a block diagram showing the signal system of the video playback device used in the embodiment of the present invention, in which 3A and 3B are video heads;
are video heads 3A, 3BK, a head amplifier for amplifying the video signal including the induced key code Kl, and 2; 5 is a signal processing circuit for FM demodulating the video signal; and 5 is a signal processing circuit for FM demodulating the video signal, which outputs a KPMFM demodulated signal. be taken out. Reference numeral 6 denotes a microprocessor sensor to which the FM demodulated signal is input, and the microprocessor 6 outputs the key code Kl.

K2 is extracted and added to the code processing circuit 7.

Also, code signals for each mode function (adult, child) are added to the code processing circuit 7 from the mode switch circuit 8, so that the key code 1. 2 is compared, and an output signal corresponding to this result is applied to the microprocessor 6 to control whether or not the FMf3i-tuned video signal is output. The output signal from the code processing circuit 7 is also used as a control signal for the audio signal and is applied from the terminal T.

FIG. 4 shows a specific circuit diagram for processing the FM demodulated signal obtained in the block diagram shown in FIG. 3. In the figure, 't'1. 'r6 is the terminal, 9 is the buffer 7
7 is an analog switch, 10 is an analog switch, 11° 4-12, 19 is an AND circuit, 13 is a gate circuit, 14 is a shift register, 15 to 18 are exclusive sieve off circuits, addition is a flip-flop, and 21 is a timer circuit. .

In the above configuration, the video signal obtained from the video head and subjected to FM demodulation is applied from the terminal T1 to the buffer 77 and the amplifier 9, and the video signal from the amplifier 9 is applied to the analog switch 1.
0 determines whether or not it is output from the terminal T6. Further, the video signal from the amplifier 9 is applied to the base of the transistor Ql to extract the key code. A clamp pulse is applied to the base of the transistor Q1 from the terminal T2 via the transistor Q2 to perform direct current regeneration, so that the key code can be reliably extracted.

The key code signal output from the transistor Ql is added to the AND circuit 11K together with the gate pulse from the terminal T3, and the output key code signal is sent to the shift register 14.
will be added to and recorded.

The 4 bits output from the output terminals ■, ■, ■, ■ of the shift register 14, for example, 1.1.1. l or 0,0
The key code signal of 0.0# is applied to one terminal of the exclusive sieve off circuits 15 to 18, and the other terminal receives the mode signal cr' obtained from the mode switch 2 as shown in FIG. o', ■, and o are added. As a result, key code signal [present] ~ ■ and mode signal 0' ~ ■'
The configuration is such that an H (high level) signal is output from the AND circuit 19 only when the two match, and this output signal is applied to the terminal i8 of the flip-flop to set its contents. Therefore, the flip-flop operates to output an H signal to the analog switch 10 and output the video signal applied from the buffer 77 amplifier 9 from the terminal T6. The timer circuit 4 is provided to provide a time lag of several seconds when a key code is lost, and is refreshed every time an H signal is output from the AND circuit 19.

If it is not refreshed for a certain period of time, add the RKH signal to the flip-flop input terminal to reset its contents.
From the flip-flop addition to the above analog switch 11
Control is performed so that the signal is added and the video signal is not output from the terminal T6.

When a video signal is output from the terminal T6, this video signal can be reproduced on a cathode ray tube or the like.

As is clear from the above description, according to the present invention, a video playback device is provided with a mode switch for each mode function, a recording medium such as a tape is recorded with a key code corresponding to the mode function, and the video playback device Since the video playback device is configured so that it operates only when the above mode function and key code match when a recording medium is set in the
When a kVC recording medium is set, the video playback f2 position can be kept stopped.

Therefore, it is possible to prevent confidential tapes or tapes with undesirable contents from being easily played back.

As another embodiment, it is also possible to give grades to the reproduced content using the constituent circuits. For example, only A mode is A
, B when in H mode and A% when in C mode, playback can be performed with operating ranges such as C, B, and A. Alternatively, it is also possible to perform playback corresponding to the mode, such as A when in A mode, B when in B mode, and C when in C mode.

The present invention is effective when applied to other video playback devices including VTRs and video discs, and can prevent recording media that should be kept secret from being used easily.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the present invention, and FIG. 2(a). (b) and FIG. 3 are waveform diagrams and block diagrams showing an embodiment of the present invention, and FIGS. 4 and 5 are both circuit diagrams showing an embodiment of the present invention. 2... Mode switch, 3A, 3B... Video head, 6... Micro pro sensor, 7... Code processing circuit, 8... Mode switch circuit, 10... Analog switch, 11. i2.19 --- AND circuit, 14 --- shift register, 15-18 --- exclusive sheep-off circuit, addition --- flip-flop, 21
...Tie circuit, K1゜K2...key code signal, 'r,'rl~T6...terminal. □ Patent applicant Clarion Co., Ltd.

Claims (1)

[Claims] The video playback device is equipped with mode switches for different mode functions.
When a recording medium into which a key code corresponding to one of the modes of the mode switch is inserted is prepared and the recording medium is set in the video playback device, the mode function of the mode switch and the key code of the recording medium match. The video playback device is configured to operate only when A video playback system characterized by: -1