KR19990001707U - VSI system with copy protection - Google Patents

Abstract

The present invention relates to a VSI system having a copy protection function used to prevent unauthorized copying of an image tape, and a conventional copy protection device inserts a copy protection signal into a video signal and thus a copy protection signal is inserted. When playing back a tape, the picture quality is poor due to the video signal being out of sync, but copying is possible. Therefore, a means was needed to solve this problem more actively.

In order to solve such a problem, the present invention includes a video signal processor 40, an oscillator 41 that takes a bias voltage V _CC , a preamplifier 42, and the like. It is connected to the rear end of the AGC stage that always maintains the output gain level of the recording reception system during the mode execution, and when the output voltage level output from the AGC stage becomes higher than the reference voltage of the zener diode 43, the active voltage becomes active. A comparator 44 for outputting a high signal and a switch connected to a rear end of the comparator 44 to receive an active high signal of the comparator 44 so as to be turned on so that the bias voltage V _CC is not applied to the oscillator 41. And a transistor (Q1) circuit.

Description

VSI system with copy protection

The present invention relates to a VSI system having a copy protection function used to prevent unauthorized copying of an image tape. In particular, when a copy protection signal is inserted into a video signal and input to the AGC terminal of a video signal processor, the comparator The high active signal is output, and the oscillation section which is applied with the bias voltage for erasing and audio recording is turned off so that when the user makes an unauthorized copy of the tape on which the copy protection signal is recorded in the video signal, the previously recorded data is not erased. Is actually made to have the reliability of copy protection.

The VSI system is an electronic device that is widely used with a TV receiver, and the conventional circuit of the system having a copy protection function by a VSI user in the VSI system is disclosed in Korean Patent Application Publication No. 1212, Publication No. 94-. 4567, the circuit block diagram of which is shown in FIG.

Here, a remote controller 21 which performs password input for copy protection, a preamplifier 22 which receives a signal transmitted from the remote controller 21 and provides it to the microcomputer 24, a function switch 23 and a microcomputer. Computer 24, deck portion 25, signal processing portion 26, vertical synchronization separation portion 28, divider 27, synchronous separation portion 29, OSD portion 30, amplifier 31, 32), rust switch 33, control head 34 and the like.

In such a system, when a user inputs a copy number for copy protection through the remote controller 21 or the like, the microcomputer 23 drives the deck unit 25 to perform recording, and the control head (a) through the amplifier (31). Providing an encryption pulse code at 34) resulted in the encryption information for copy protection being recorded on the control track of the tape being recorded.

For example, the encryption information recording process for copy protection in the control track of the tape in such a system is shown as shown in FIG.

In this case, it is checked whether the system is in the recording mode, and in the recording mode, the recording operation is performed (steps 310 and 320).

After that, the character display screen is output through OSD (Step 330). If the password input is completed, the password is entered. If the password is completed, the set password is recorded on the control track. When the process went to the input step or the end step, and not in step 310, the selected operation was performed (steps 340 to 370).

However, in such a conventional system, copy protection password information is recorded on a control track of a recording tape for copy protection, and a copy operation cannot be performed when there is no password input, but the password information is registered in a set on an OS program. When the tape copy is performed using a set in which such cipher information is not registered, the copy protection cipher record is disabled and a copy operation is arbitrarily performed.

Another prior art copy protection circuit includes a first VCR1 for reproducing contents recorded on an original tape and a second tape for reproducing contents of an image on a new tape as shown in FIG. The VCR2 is connected to each other through a video output line and a audio output line, and has a sudden level change in the video output line Video through which the video signal is output, and the signal is out of sync. The copy protection signal inserting circuit 10 for inserting the conduit was configured.

The conventional copy protection circuit having the above configuration reproduces the video signal and the audio signal recorded on the original video object in the first VCR1 and outputs them through the video output line and the audio output line. The copy protection signal insertion circuit 10 generates a copy protection signal having a sharp level fluctuation and a synchronization loss for copy protection, and puts it in the vertical blanking period of the video signal output to the video output line. The video signal mixed with the prevention signal and the audio signal passing through the audio output line Audio are recorded on a new tape in the second VCR2.

Therefore, when playing a new tape, it is possible to play back video signals without any problem.However, when copying a new tape to another tape, a copy protection signal recorded with the video signal causes problems such as interference on the copy screen. It is not allowed to be copied by the general consumer.

However, such a conventional copy protection circuit inserts a signal for copy protection into a video signal and reproduces a tape in which the copy protection signal is inserted. Therefore, a means was needed to solve this problem more actively.

An object of the present invention is to provide a method of effectively preventing copying by allowing a user to copy a tape having a copy protection signal recorded thereon in a video signal so that the recording proceeds without erasing the previously recorded data. It is to provide a VSI system having a copy protection function to be reliable.

In particular, the present invention is directed to a VSI system including a video signal processor, an oscillator, and a preamplifier for applying a bias voltage (V _CC ) so as to realize the object of the above example. A comparator connected to a rear end of the AGC stage that always maintains a constant gain level and outputting an active high signal when the output voltage level output from the AGC stage is higher than the reference voltage of the zener diode, and outputs an active high signal. And a transistor (Q1) circuit for switching so that the bias voltage (V _CC ) is switched on by receiving an active high signal of the comparator and being turned on.

Hereinafter, more specific features of the present invention will be understood by describing the same in detail with the accompanying drawings.

1 is a circuit block diagram of a conventional Video Cassette Recorder (VCR) system with copy protection;

Figure 2 is an example of the copy protection encryption recording program in Figure 1,

3 is a block diagram showing a conventional copy protection signal insertion circuit;

4 is a system circuit block diagram having a copy protection function according to the present invention.

** Explanation of symbols on the main parts of the drawing **

40: video signal processor 41: oscillator

42: preamplifier 43: zener diode

44: comparator 45: full width sweep head

46: Audio muting head 47: Audio recording head

As shown in FIG. 4, the present invention includes a video signal processor 40, an oscillator 41 receiving a bias voltage V _CC , a preamplifier 42, and the like. Is connected to the rear end of the AGC stage which always maintains the output gain level of the recording reception system during the recording mode of the recording mode, and compares the output voltage level output from the AGC stage with the reference voltage of the zener diode 43 so as to exceed the reference voltage. When the comparator 44 outputs an active high signal and the comparator 44 is connected to the rear end of the comparator 44, the active high signal of the comparator 44 is turned on so that the bias voltage V _CC is not applied to the oscillator 41. And a transistor Q1 circuit for switching operation.

Referring to the operation of the present invention configured as described in detail as follows.

First, the user inserts the original program tape and the blank tape into the deck unit (not shown), such as VSI or VSI or duplexer, and copies the program contents of the original tape to the blank tape. The recording command is provided to the microcomputer (not shown) through a key input unit (not shown).

At this time, the microcomputer receives the original program signal from the outside while driving the blank tape and provides the recording signal to the video signal processing unit 40 through the AGC stage.

In particular, the AGC stage automatically adjusts the input signal level when it changes so that the output gain level is always constant.

However, if a copy protection signal is inserted into the received video signal and input together to the AGC stage, the AGC stage outputs a higher voltage level signal corresponding thereto.

In addition, a comparator 44 is provided at the rear end of the AGC stage. The comparator 44 compares an output voltage level output from the AGC stage with a reference voltage of the zener diode 43 to generate an active high signal. Will print.

That is, when the composite signal mixed with the received video signal and the copy protection signal is applied to the (+) input terminal of the comparator 44 when the tape is copied and becomes larger than the reference voltage of the zener diode 43, the comparator 44 becomes active high. The signal is output and the transistor Q1 is turned on accordingly.

When the transistor Q1 is turned on through such a series of operations, the erase and audio recording bias voltage V _CC falls to the ground point, and thus oscillation of the oscillator 41 is stopped.

That is, the oscillation of about 70 KHz supplied to the full-width erasing head 45, the audio removing head 46, and the audio recording head 47 where the audio signal is recorded, respectively, is operated to remove the video and audio signals recorded on the copy tape. The output will stop.

Thus, the 70 KHz oscillation output is not supplied from the preamplifier section 42 to the full-width erasing head 45, the audio erasing head 46, and the audio recording head 47, thus recording on the audio / video track of the copy tape. The recorded contents are not erased but are superimposed and recorded.

In this case, the audio signal output from the audio signal processor (not shown) is also not copied from the oscillator since there is no output.

For reference, at this time, if a positive video signal having a constant output voltage level (eg, having a voltage less than the zener diode reference voltage) having a constant output voltage level passing through the AGC stage is input to the (+) input terminal of the comparator 44 When the voltage level value is applied, the comparator 44 outputs a logic 0 signal, thereby turning the transistor Q1 off.

Therefore, in this case, the oscillation unit 41 normally outputs 70 KHz oscillation output, and the oscillation output is supplied to the full width erasing head 45 and the audio erasing head 46 to erase the video and audio signals recorded on the tape.

At the same time, the oscillation output from the oscillator 41 is mixed with the audio signal output from the audio signal processor and provided to the audio recording head 47.

Therefore, after the contents recorded on the tape are erased, video signals and audio signals are normally recorded.

As described above, the VSI system having the copy protection function according to the present invention automatically outputs a high active signal by the comparator 44 when the copy protection signal is inserted into the video signal and input to the AGC terminal of the video signal processing unit 40. As a result, the oscillation unit 41, which takes the bias voltage V _CC for erasing and audio recording, is turned off, so that when a user makes an unauthorized copy of a tape on which a copy protection signal is recorded in the video signal, the previously recorded data is not erased. It is possible to actually have the reliability of copy protection.

Claims (1)

In a VSI system including a video signal processor 40, an oscillator 41 to which a bias voltage V _CC is applied, a preamplifier 42, and the like, an output gain level of a recording reception system when a recording mode of the system is performed. And a comparator 44 connected to a rear end of the AGC stage that always maintains constant, and outputs an active high signal when the output voltage level output from the AGC stage is greater than the reference voltage of the zener diode 43. And a transistor Q1 circuit connected to a rear end of the comparator 44 so as to be turned on by receiving an active high signal of the comparator 44 so that the bias voltage V _CC is not caught by the oscillator 41. VSI system having a copy protection function, characterized in that.