JPH01129582A - Recording medium and processor for signal - Google Patents

Abstract

PURPOSE:To prevent a recording medium from being copied by making a synchronizing signal absent partially or entirely and inserting a digital signal in a period other than a video signal period. CONSTITUTION:A special image signal which has no vertical synchronizing signal, a digital signal (d) with the same polarity with the video signal in a concentrated information signal period 5, and a horizontal synchronism inverting signal rhs in a horizontal blanking period 2 is recorded on a video cassette tape. The start point of a vertical synchronizing signal which is inserted newly is set shifting from a reference point by a specific period deltat. The deltat of the special image signal which is reproduced first from the recording medium is supplied as different information from the manufacturer of the recording medium to a user, who sets a signal processor according to the information. The signal processor extracts the digital signal in a centralized information signal period from the playback signal and then inserts equalized pulses, the horizontal synchronizing signal, and vertical synchronizing signal according to the reference point and deltat.

Description

[Detailed Description of the Invention] <Field of Application of Industry-L> The present invention relates to a recording medium that records a special image signal lacking a synchronization signal and is provided to a limited number of users, and a signal processing method for the special image signal. Regarding equipment.

<Terms> As shown in FIG. 1, the composite image signal referred to in this specification has a video signal period (1), a horizontal retrace period (2), and a vertical retrace period (3). A signal with a video signal (e) that can be displayed on the scanning line of a built-in playback device,
In addition, in order to properly retrace the electric R-beam of the video reproducing device, the horizontal synchronizing signal (HS) is provided during the horizontal retrace period, and the vertical synchronizing signal (VS), equalization pulse (HP) and horizontal synchronizing signal are It means a signal that has a debt during the vertical retrace period. Also,
The special image signal in this specification is a signal that has an analog signal related to video during the video signal period, but unlike a composite image signal, it lacks part or all of the synchronization signal, so if it is used as it is, the electronic The beam cannot be returned normally. Furthermore, since this special image signal is not restricted by the retrace period, the ratio of the video signal period to the ■ field is not necessarily constant. Moreover, if a synchronization signal is appropriately inserted into this special image signal, a signal similar to a composite image signal will be obtained. The period around the insertion of the synchronization signal does not include either the synchronization signal or the video signal, and can be used for an information signal other than the video signal, that is, a digital signal. moreover,
A period of digital signals can be created independently of the insertion of a synchronization signal, and the period composed of digital signals in the special image signal is not necessarily related to the return line of the electron beam.

Therefore, in this specification, a period composed of digital signals that is slightly long enough to insert a vertical synchronization signal is called a concentrated information signal period, and is also distributed in each horizontal scanning line period and sandwiched between video signal periods. This short period is called the distributed information signal period.

In this specification, polarity refers to whether the value obtained by subtracting the pedestal level value (pl) from the signal value is positive or negative (Figure 1), and polarity reversal refers to the sign of the value. This means that it is reversed (Figure 2). Horizontal synchronization signal (hs)
A signal whose polarity is inverted is referred to herein as a horizontal synchronization inversion signal, and is indicated by rhs in the figure.

The digital signal referred to in this specification means a signal whose content is digital data composed of codes, regardless of the presence or absence of modulation, modulation method, and polarity. Furthermore, synchronization signals are not included in the digital signals in this specification. In addition, the analog signal referred to in this specification means a signal having as its content analog data composed of a continuous value or a large number of nearly continuous values.

<Prior art, its problems, and purpose of the invention> If a recording medium records everything necessary for playback and re-recording along with a video signal, anyone can use a V1'R and a video cassette chip. However, it is easy to make copies of recording media. Preventing easy copying of recording media is necessary from the perspective of securing copyright.

When recording with Ondo's home VTR, a synchronization signal is used to stabilize the operation of the recording device. However, the stability of operation during playback is achieved using the control signal of the control track, and a synchronization signal is usually not necessary. Therefore, if the synchronization signal is missing, although the recorded signal may be reproduced, it will not be possible to make a normal copy.

When a video reproduction device such as a television set uses signals reproduced from a recording medium to reproduce images on a screen, electron beams are scanned on the screen, but this cannot be done without a synchronization signal. In other words, synchronization signals are essential for video playback. It is also important that the position of the synchronization signal is accurate; if the horizontal synchronization signal is shifted even slightly between adjacent scanning lines, the reproduced image will be distorted, and if the vertical synchronization signal is shifted, the reproduced image will be split into two. or Therefore, in the case of a special image signal that lacks a synchronization signal, the signal must be configured so that the synchronization signal can be inserted accurately later.

On the other hand, the blanking period related to the synchronization signal accounts for approximately 20% of the entire composite image signal, and if it is possible to record without the synchronization signal, this blanking period can be used to record other signals. , it is possible to record a signal with increased information density as a whole signal, and it is possible to reproduce a signal with increased information density from a recording medium on which such a signal is recorded.

<Outline of means for solving the problem> A special image signal was recorded in which the synchronization signal included in the composite image signal is partially or completely absent, and a digital signal is inserted in a period other than the video signal period. Create a recording medium. For the reproduced signal, a signal processing device is used to extract the tintal signal and insert a synchronization signal in relation to the position where the digital signal was included in the original special image signal. , convert the composite image into a belief similar to the belief. Alternatively, both a signal for retracing the electron beam in the video reproducing device and a signal U obtained by extracting a digital signal from the special image signal are output to the video reproducing device.

<Embodiment> As an example of implementing the present invention, as shown in A and B in FIG. As a special image signal that has a digital signal (d) and also has a horizontal synchronization inversion signal (rhs) during the horizontal retrace period (2),
First, an example recorded on a video cassette will be explained. As shown in FIG. 5, each video track recorded on the magnetic tape in this example includes an area of concentrated information signal period (dan), an area of video signal period and horizontal retrace period (-!+2) There is.

In this example, the concentrated information signal period first includes a portion approximately at the pedestal level value, followed by a digital signal having a start signal at the beginning.

Therefore, the starting point of the digital signal can be reliably read as the point of the first high signal value input after switching the playback head by the head switching pulse (cp), and this starting point is used as the reference point. . The starting point of the newly inserted vertical synchronization signal is a specific period (δt
) and set it offset (Fig. 3 B, C). Note that the starting point of the vertical synchronization signal coincides with the reference point when δt is O, lags behind the reference point when δt is positive, and advances from the reference point when δt is negative (however, it is delayed by one field). δt of the special image initially reproduced from the recording medium
is given to the user as separate information from the manufacturer of the recording medium, and the user operates the signal processing device based on that information.
do. In other words, only if this information on δt is obtained,
The precise timing of the synchronization signal to be inserted into the reproduced special image signal can be adjusted. If δt changes in the middle of the recording medium, the digital signal before the change contains information about δt, and the signal processing device detects the new δt at the point of change.
Cent t. After extracting the digital signal of the intensive information signal period from the reproduced signal, the signal processing device inserts an equalization pulse, a horizontal synchronization signal, and a vertical synchronization signal based on the reference point and δt. -8 = The starting points of the vertical synchronization signals of the even field and the odd field are δt and δt so that they are shifted from the starting point of the concentrated information signal period of the reproduced signal by approximately (n+]/2) + (and n I-1, respectively). A reference point is set. Note that n is an integer, and 11 is the horizontal scanning period. The value of n determines the height of the video displayed on the screen of the video playback device. Also, the height of the video displayed on the screen of the video playback device is determined. The length increases or decreases, and the number of horizontal synchronization signals inserted in the intensive information belief period increases or decreases accordingly.

Regarding the horizontal synchronization inversion signal during the horizontal retrace period in this example,
From immediately after the intensive information signal period until the start of the next intensive information signal period, at regular intervals (36/ITC), i#]
(approximately /l QTc) is inverted, thereby inserting a horizontal synchronizing signal (FIG. 3D). However, T
c=0.1746μ5O-1- In the case of the embodiment described above, the signal flows in the signal processing device as shown in FIG. The digital signal is divided into a digital signal (d) and a video signal (C), and a signal (V) indicating the reference point is obtained from the start part of the digital signal, and a synchronization adjustment circuit adds δt to this signal to obtain appropriate synchronization. By timing the processing and inserting equalization pulses and synchronization signals (including inversion), as a result,
The signal (i) is similar to the composite image signal.

In another embodiment, in a special image signal (FIG. 3E) which has a digital signal of opposite polarity to the synchronization signal during the intensive information signal period and in which all the horizontal synchronization signals are normally present, the signal processing device performs the above processing. No processing is necessary for the inversion of . Furthermore, in an embodiment in which a special image signal with an equalization pulse inserted at the end of the concentrated information signal period is recorded, only the vertical synchronization signal and horizontal synchronization signal are inserted in the concentrated information signal period.

Next, with special image signals as shown in Fig. 4A and B,
There is no vertical sync signal, equalization pulse, or horizontal sync signal,
Concentrated information signal period (5) and distributed information signal period (/I
) describes an embodiment of a video cassette tape on which a special image signal having a digital signal having a polarity opposite to that of the video signal (e) is recorded. As shown in FIG. 5B, each video track recorded on this tape includes an area of concentrated information signal period (alternate), an area of video transmission period and a distributed information signal period (-!4- There is 4-).

In this example, the reproduced signal can be easily divided into a digital signal and a video signal depending on the polarity of the signal value. The beginning portion of the digital signal is different between the concentrated information signal period and the distributed information signal period, thereby distinguishing between the digital signal in the concentrated information signal period and the digital signal in the distributed information signal period.

The starting point of each digital signal of the concentrated information signal period and the distributed information signal period is used as a reference point for each of the vertical synchronization signal and the horizontal synchronization signal. In addition, the time difference δtl + δt from the reference point to the start point of each of the vertical synchronization signal and the horizontal synchronization signal is processed by the signal processing device. When properly inserted, a signal similar to the composite image signal shown in FIG. 4C is produced. The length of both the concentrated information signal period and the distributed information signal period can be changed depending on the amount of information, but in the illustrated example, the reflection of II] (horizontal scanning period) = 1
1- The length of the image signal period is shorter than that of the composite image signal, and the distributed information signal period is longer than the horizontal retrace period of the composite image signal.

In this case, by changing the value of δt, it is possible to shift the image displayed on the screen of the image reproducing device left and right.

In this embodiment, in the signal processing device, the signal processing is performed by the seventh
The process is carried out as shown in the figure, and the special image signal (g) output from the recording/playback device is converted into a digital signal (d) by the digital signal extraction circuit.
) and video signal (e), and the signal (V
) and a signal (h) indicating the reference point for the horizontal synchronization signal are obtained, and the synchronization adjustment circuit calculates δt1 and δt, respectively.
In addition, the equalization pulse, vertical synchronization signal, and horizontal synchronization signal are inserted with accurate timing, and a signal (i) similar to a composite image signal is generated. In another signal processing device (an embodiment of the device according to claim 13),
As shown in FIG. 8, the pulse signal (p) is output separately from the video signal without inserting an equalization pulse or a synchronization signal, and is directly input to the synchronization circuit of the video reproduction device.

In the embodiment (FIG. 4D) in which a special image signal is recorded in which the synchronization signal has a digital signal of the same polarity during the intensive information signal period, but the horizontal synchronization signal is normal, the implementation of FIG. In the same way as in the example, insert the synchronization signal and equalization pulse only during the intensive information signal period.

Furthermore, in the embodiment (FIG. 4E) in which a special image signal having a digital signal of opposite polarity to the video signal during the intensive information signal period and a horizontal synchronization inversion signal during the horizontal retrace period is recorded, the above-mentioned A synchronization signal and an equalization pulse are inserted into the concentrated information signal period in the same manner as in the embodiment of FIG.

In the embodiment using a video disc, the recording position and polarity of the digital signal in the special image signal to be recorded are the same as in the embodiment using a video cassette tape, and the processing of the playback signal is also the same, but each field is It is easier to identify the starting point.

FIG. 9 shows an example of a signal reproduction processing system using the signal processing device according to the embodiment of the present invention. 8, the Shingo processing device (9
) is connected to the recording/playback device (7) and the video playback device (8) by a cord, and the signal processing device converts the seven-knot part (a) of the time difference (δ1+) regarding the vertical synchronization signal and the time difference (δ1) regarding the horizontal synchronization signal. .) has part (b).

In B, the signal processing device (9) is coupled to a recording/playback device. In C, the signal processing device (9) is coupled to the video reproduction device.

<Effect of the invention> According to the present invention, copying of a recording medium can be prevented.

That is, if you try to copy without using the signal processing device of the present invention, the synchronization signal is missing, so the VT
R cannot operate stably. If an attempt is made to copy using the signal processing device of the present invention, digital data will be lost. In addition, other information not included in the recording medium is required for normal video playback, and the target of use can be limited. Furthermore, it becomes possible to reproduce signals with increased information density.

[Brief explanation of the drawing]

FIG. 1 schematically shows an example of a waveform near the start point of the vertical retrace period (3) of a composite image signal, and B is an enlargement of a portion of A. FIG. 2 schematically shows waveform examples of a horizontal synchronization inverted signal (rhs), which is the polarity of the horizontal synchronization signal, and a video signal (e) having the same polarity. 3A and 3E are schematic waveform examples of special image signals, B is a partial enlargement of A, and C and D are schematic waveforms of B processed by the signal processing device of the present invention. Fourth
In the figures, D and E are schematic waveform examples of special image signals, B is a partial enlargement of A, and C is a schematic waveform of B processed by the signal processing device of the embodiment of the present invention. FIG. 5 is a schematic diagram of videotape recording according to an embodiment of the present invention, and a video track of one field is shown as an example. 6 to 8 are block diagrams schematically illustrating the flow of signals when the signal processing device according to the embodiment of the present invention is used. FIG. 9 is an example of a signal reproduction processing system using the signal processing device according to the embodiment of the present invention. Figure 3 Figure 4 Figure 7 Figure 8 Large bite Figure 9

Claims (13)

[Claims] (1) A recording medium that lacks a synchronization signal and records a signal that has a period composed of an analog signal related to video and a period composed of a digital signal. (2) The recording medium according to claim 1, wherein the synchronization signal missing from the recorded signal is a vertical synchronization signal. (3) The recording medium according to claim 1, wherein the synchronization signal missing from the recorded signal is a horizontal synchronization signal. (4) The recording medium according to claim 1, wherein a signal having a horizontal synchronization inversion signal is recorded during the horizontal retrace period. (5) The recording medium according to claim 1, wherein the digital signal is a signal having the same polarity as the video signal. (6) The recording medium according to claim 1, wherein the digital signal is a signal having a polarity opposite to that of the video signal. (7) The recording medium according to claim 1, wherein a signal is recorded in which the start point of the digital signal is shifted by an arbitrary period from the start point of a synchronization signal inserted when converting into a composite image signal. (8) The recording medium according to claim 1, wherein the recording medium is recorded using a magnetic tape. (9) The recording medium according to claim 1, wherein the recording medium is a video disc. (10) Signal processing characterized by inserting a synchronization signal into the signal when a signal lacking a synchronization signal and having a period composed of an analog signal related to video and a period composed of a digital signal is input. Device. (11) The signal processing device according to claim 10, wherein the synchronization signal to be inserted is a vertical synchronization signal. (12) The signal processing device according to claim 10, wherein the synchronization signal to be inserted is a horizontal synchronization signal. (13) When a signal is input that lacks a synchronization signal and has a period consisting of an analog signal related to video and a period consisting of a digital signal, a signal for returning the electron beam of the video playback device is output. A signal processing device characterized by: