JPS5844873A - Television signal recording and reproducing device - Google Patents

Abstract

PURPOSE:To view and listen to a specific program by a specific viewer only, by storing a key signal added at the end of the specific program and descrambling a television signal based on the key signal. CONSTITUTION:A signal received at a tuner 4 is recorded in a recorder and reproducer 5. A signal reproduced from the recorder and reproducer 5 is modulated at a vacant scrambling signal at a modulator 6 and inputted to a receiver 3. The scrambled signal from the recorder and reproducer is inputted to the receiver 3 via a decoder 2. The end of the scrambled signal is attached with a key signal for descrambling and the reproducing signal from the recording and reproducing device 5 is descrambled based on the key signal, by storing this key signal at the decoder 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for recording and reproducing television signals by scrambled broadcasting.

In recent years, a scrambled broadcasting system has been proposed, in which a broadcast station scrambles and transmits a specific program so that only viewers who have a contract with the broadcast station and have a decoder can view this program. A small-scale experimental broadcast is being conducted. “In scrambled broadcasting, a broadcast station transmits a scrambled signal by changing the level of the television signal of a specific program at an arbitrary period of time or by changing the order of the signals. Therefore, the television signal by scrambled broadcasting Even if you receive the program with a normal TV receiver, you will not be able to view the correct image or sound.Only listeners who have signed a contract with the broadcasting station will be able to restore (descramble) the scrambled signal with a decoder and reproduce the original version of the program. Images and audio can be viewed.

The present invention provides a system device suitable for once distributing and reproducing such scrambled broadcast television signals, and embodiments of the present invention will be described below with reference to the drawings.

This embodiment is designed to satisfy the following conditions.

(1) It is not possible to simultaneously descramble a scrambled broadcast program while receiving it.

In other words, it is not possible to view the correct program in real time.

(2) Programs using scrambled broadcasting are temporarily broadcast on VT.
You cannot watch it unless you record it in R.

(3) A tape on which a scrambled broadcast program is recorded cannot be viewed correctly unless it is played back on a VTR with a decoder.

(4) VTR can be used in any format.

(5) When adding a decoder, the existing V 'l'
Changes in It will be kept to a minimum.

(6) Scrambled broadcasting is broadcast using free time during normal broadcasting hours, such as late at night.

1111i1i [Figure 2 C VTR (11, decoder (2+
An example of the connection relationship between the two receivers (3) is shown, and corresponding parts are given the same reference numerals.

In FIG. 1, a VTR (11) is a conventionally known helical scan type VTR. A built-in modulator (6) etc. is built in to convert the reproduced video signal and audio signal of normal broadcasting into vacant channel frequencies.This modified Al signal is sent from the output terminal (7) to the receiver (3).
) is added to the antenna terminal. On the other hand, recording and reproducing equipment (
The scrambled video and audio signals from 5) are applied to the decoder (2) from the output terminal (8) and are descrambled to become regular signals. This signal is input to the input terminal (
9), passes through the VTR again, and connects to the line out terminal 00)
t7 is added to the line-in terminal of the receiver (31).

Figure #12 shows a case where the decoder (2) has a built-in modulator (Ill), and the descrambled signal is sent to the modulator 011.
convert it to an available channel frequency and apply it to the antenna terminal of the receiver (3). If the descrambled signal is not modulated, this signal is applied to the line-in terminal.

FIG. 6 shows the contents of signals sent out when a certain program is sent out in scrambled broadcasting.

In the audio channel, first, a start signal Sl indicating that the program is a scrambled broadcast program is added, and then a key discrimination signal S for discriminating the glaze of a key signal S, which will be described later, is added. Then, when the program ends, the scrambled audio signal S, of the program is not sent out.
After the write start signal S4 for writing the key signal S, into the memory is applied, the key signal S, for descrambling the scrambled signal S, is applied. Finally, a write stop signal S6 is applied.

In the video channel, the scrambled program video signal S7 corresponding to the signal S is added, and then the partial ζ sync signal V corresponding to the signals 84 to S6 is added.
D and horizontal synchronization signal HI) are added.

Signals s, , excluding programs in the audio channel
.

This binary code signal is modulated into 'E'8 and superimposed on the television signal. In this case, "1" of the binary code is modulated to, for example, 1000 Hz, and "0" to, for example, 600 Hz.

When performing scramble broadcasting late at night, start signal S1
is detected and the VTR (11, decoder (2) and receiver 1
The image machine (3) may be operated.

The key signal S is determined as follows.

For example, consider a case where a signal of a certain program is scrambled by changing its level in units of one field. In this case, for example, the signal level of an arbitrary field period in an arbitrary predetermined period of the video signal is lowered by 75i, and this is repeated every predetermined period.

For example, if the above predetermined period is 5 fields and the level of the 1st and 6th fields of the 1st to 5th fields in this period ξ is lowered, in order to descramble on the receiving side, It is sufficient to increase the gain of the amplifiers of the first and third fields. If the key for increasing this gain is "1", the key signal can be represented by a code pattern of l'-01100J. Note that the audio signal is also scrambled and descrambled in the same manner.

In this embodiment, after the recording of the program is completed in the VTR (11), the key signal S is stored in the memory built in the decoder (2).
, key signal 8. is descrambled by constantly reading out the signal and comparing it with the stable signal. The code of signal S is changed for each program, or hourly, daily, weekly, or monthly, so that its contents are not known to anyone other than the subscriber. Therefore, if a large number of programs are recorded, as many types of key signals as Memo IJ+1 will be written. Therefore, in order to determine which key code should be used to descramble a desired program during playback, a key determination signal S is added to the program inadvertently.

Further, in this embodiment, the key signal 8. is added to the end of the program. As a result, it is not possible to watch scrambled broadcasts in real time, and it is necessary to watch scrambled broadcasts on a VTR.
(The program is made so that the correct program cannot be viewed unless it is recorded on the tape once in II.If the key signal S is not recorded on the tape, even if a copy tape is made, the key will not be visible.) Therefore, descrambling is impossible.Even if a key signal is recorded, descrambling is impossible unless there is a decoder.The horizontal and vertical synchronization signals HD and VD are used to obtain the clock when writing the key signal. added to.

Next, an embodiment of the decoder (2) will be described with reference to FIG. 4. The 0 decoder (2) includes an audio signal input terminal 05), a video signal input terminal 06), an audio signal output terminal +171. Video signal output terminal 0 barrel, key signal demodulation circuit α→, synchronization separation circuit Q
(1), timing circuit (2I), code discrimination circuit (phantom, memory (c), audio signal descrambling circuit (to)
, video signal descrambling circuit ■■ and switch (E)
(27) (Constructed as shown in the figure by 28+, etc.)

During recording, the switch (26+ (21'll) is opened,
Switch (5) is closed. Signals S and -S6 are sequentially applied to the input terminal (151) from V'I'll in the previous stage, and signals By, VD, and HD are applied to the input terminal 06. Incidentally, at this time, the VTR is set to the recording mode E-E, and a monitor signal is applied to the input terminal t15) (Iiii).

When the start signal SL shown in FIG. 6 is first detected by the code discrimination circuit (221) from the signal applied to the input terminal 1151, each circuit is operated based on this detection. Next, the key discrimination circuit No. 41 S is detected. When the type of key signal Sll of the program is detected and the type of key signal Sll of the program is determined, the determination signal S8 is written into the memory (c). The signals VD and IID are extracted from the scrambled video signal to drive the timing circuit 121). When the program is finished, the input start signal S4 is detected and the memory (2 increment) enters the write mode of the key signal S11. Then, the demodulation circuit (1
9 demodulates the FSK-modulated key signal S to generate a binary code key signal. This key signal is the timing circuit Q
It is synchronized with the clock through υ and written into the memory (c) lζζ corresponding to the front row discrimination signal S8.

During this time, signals VD and HD are applied from the video channel to obtain a write clock. In addition, the code discrimination circuit (2
2) When the write start signal S4 is detected (!-), this detection signal is added to the VTR as shown by the dotted line in the figure, and the operation of the recording circuit is stopped to prevent the key signal S from being recorded on the tape. When the writing of the key signal S1 is completed, the oath stop signal S6 is detected, and
1 loading operation stops.

As described above, the scrambled video signal, audio signal, and other signals (Sl, S2, S4 to S6, etc.) are recorded on the tape, and the key signal and the type of key signal of the program are written in the memory +23. It will be done. The above-mentioned operation is performed every time a scrambled broadcast program is recorded, and a key signal and a key discrimination signal for each program are written in the memo IJ-(231).

Next, during playback, the VTR (11) goes into playback mode and the switch □□□i I)l! + is closed and switch C
γ) is opened. A signal obtained by demodulating the signal reproduced from the audio track of the desired program recorded on the tape is added to the input terminal (t6).
A signal obtained by demodulating the signal reproduced from the video track of the program is added to . First, when the reproduced key discrimination signal S is detected by the code discrimination circuit (22I),
The corresponding key signal written in the memory 3J is read out. This readout is performed at the end of playback,
The read key signal is applied to the test clamp circuit 41@. Descrambling circuit CI! 41 t25)
descrambles the input scrambled audio and video signals based on the code pattern of the key signal. In this case, if the scrambling method is based on the level change described above, the increment [1] degree of the period during which the level is lowered is increased. When the method of random scrambling is based on permuting the order of signals, the input signal is delayed and the order of the signals is restored to the original order during this delay time. Descramble episode MG4) (
The audio and video signals restored to their original form at 21 are applied to the receiver via an output terminal aη08). Furthermore, S°
By adding a code corresponding to the program to the start signal S1 or the key discrimination signal S, it may be used to locate the beginning of the tape during playback. Also, memo Q - (2
The key discrimination signal from 3+ may be read out manually.

Next, several embodiments of the scrambling method will be described.

When performing scrambling, the scrambled 1
When No. B is received and read on a normal television receiver, it is necessary to make the contents as hidden as possible and to make it impossible to easily decipher the key code for descrambling. On the other hand, in V'11R, various signal processing is performed during recording, and various obstacles occur before the scrambled signal passes through the recording system and is recorded on the tape.

This damage sustained during recording will remain as incomplete descrambling during playback, impairing image quality. Therefore, in the method of the present invention in which scrambled broadcasts are once recorded on a VTR, it is important that the scrambled signal passes through the recording system without problems, and especially in the case of a home VTR, the scramble effect can be achieved without disturbing the correlation between signals. It is desired that the signal size be large and that descrambling in the decoder be easy.

The various methods described below take the above points into consideration.

First, a video signal scrambling method will be described.

(11. V-flicker method This is the simplest method and is a method in which the level is changed based on one field unit as shown in Figure 5. In the case shown in the figure, the level of the fields of 4th, 7th, and 9th cuts is 2～
3dB lower. The sensitivity of the human eye is particularly high to surface flicker, so even slight variations in brightness can produce a scrambling effect. In the example in Figure 5, marker signal S9 is inserted every 10 fields, and kneading is defined as one cycle. I'm trying to scramble 0 Human visual characteristics are 10-2
Since a flicker of about 0 Irz is most felt, the key code pattern can be determined using this period.

In this case, only the Y signal may be used, but the 0 signal (chroma signal)
Since the ratio of the 0 signals changes temporarily, it is better to change the level N of the 0 signal at the same ratio. In that case, the broadcasting station will
It can scramble 100% composite signals without overmodulating the chroma.
+,! Since the AOO operation of '-machine side 1 is usually slow, it is possible to add a scrambling effect of gray flicker by burst tracking. Note that the burst signal also changes in level J:
This simplifies the scrambling process, and if the burst signal level is kept constant, the level change can be made large, although the process is somewhat more complicated.

On the other hand, VTRs use AC (-
] Since it is designed to enable high-speed response, recording and playback can be performed without any problems.

FIG. 6 shows an example of a scrambling circuit for performing the flicker method.

Based on the VD and HD extracted by the synchronization separation circuit 03 from the Y+0 signal applied to the input terminal 01), the setup detection circuit (to), marker signal generator c3 (a), and scramble code generator 05I are operated. . When the switch α;) is opened and closed according to the scramble code, the level of the Y+0 signal is changed and scrambled according to the code pattern in synchronization with field detection by the set-up detection circuit p31. This scramble signal is sent to the adder 0η
The signal is added to the sum of the marker signal from the adder and the scramble code and selected. In this case, the scramble code becomes the key signal S.

(2) Chroma flicker method This method scrambles the C signal by changing the phase of the burst signal on a field-by-field basis. This method modulates only the phase, so V
Even if it passes through the TR, it does not affect 87N etc. and does not disturb signal correlation. Therefore, it is possible to improve the signal quality when descrambling. Further, it is possible to implement the method without performing YO separation, which causes signal deterioration.

FIG. 7 shows an example of a scrambling circuit for carrying out the above method.

Y + 0 added to the input terminal (39) (No. 8 is)
The burst signal is extracted at burst gate +401 and applied to the casting machine (41). No. 8 is a phase shifter (421~(4-1, 90" and 1, respectively)
The phase is shifted to 80° and 270° and applied to the switch (4). The scramble code generator (47) is driven by the VD and HD from the synchronous separation circuit (41i1), and the switch (45) is sequentially driven by the scramble code. ) is cut off and the burst signal is sequentially shifted from O゛ to 27[]'' (0 is added to the Y10 signal by the 1 adder (4I) and sent out. When the phase of the burst signal is rotated, the receiver's APO can normally follow each field, so the hue changes from field to field.In this example, the hue changes randomly with 12Hz chroma flicker, resulting in scrambling. During VTR F recording, various control systems can follow the burst phase sufficiently, so it is recorded on the tape in that form.Therefore, when recording in 74, decoding in the reverse sequence returns the original hue. .

In this method, at least two phases may be combined and switched, and more phases may be switched in various combinations. Specifically, as in method (11) above, a marker signal may be inserted every cycle of the combination.

(3) Signal replacement method In the example shown in Figure 8, the IH period is divided into two, and the second half is Δ11.
61) is moved to the (-H) part of the next H period.If this method receives the signal with the usual image reception, the result will be as shown in Figure 9. The normal image becomes a horizontally reversed screen.

FIG. 10 shows an embodiment of a scrambling circuit according to the above method.

The input signal is delayed by a 0 and 5H delay circuit (4 barrels) consisting of OOD and BBD41, resulting in a scrambled signal as shown in Fig. 8.
) is driven by a clock that is 0 times the HD frequency. In addition, there are two switches! in) 51) is opened during the horizontal blanking period.

In order to further enhance the scrambling effect and to make descrambling more difficult, a regular signal may be inserted field by field into the scramble signal shown in FIG. If this insertion is performed using a key code, it will not be possible to decode it easily. To implement this method, for example, in FIG. 10, a switch is used to switch between the input signal or the signal obtained by delaying the input signal h by 111 and the 0.5H delayed output, and the input signal or It is a good idea to select 1H delayed output.

Alternatively, as shown in FIG. 11, the regular screen may be divided into four parts and their order may be changed. This case can be easily realized by appropriately combining ↑ delay circuits, 10 delay circuits, etc.

(4) Ghost method As shown in Figure 12, the input signal is delayed by about 1 μm,
This method creates a pseudo-ghost by changing the switch for each field.

(5), 1H each in time reversal method memory! :This is a method of reading out the input signal in the opposite direction to the direction in which it was written, and combining it with the regular field in units of one field.0 Figure 13 shows an example of a scrambling circuit, in which the input signal is A, / D-converted edge data is written to two 1H memories alternately via a switch that changes for each IH, so that when one is being written, the other is read. At this time, when writing, the up/down counter is counted up, and when reading, it is counted down and read in the opposite direction.

The read signal is taken out via a switch that changes every 1H, and converted into D/A. This D/person output and the original input signal are alternately output one field at a time via a switch that changes over each field. When this scrambled E signal is received by a normal receiver, the screen will display the original image and the reversed image.

Next, a method for scrambling audio signals will be described.

(1) Signal replacement method @14 As shown in Figure 14, this is a method of replacing the order of six fields, for example. In the case of audio, if the unit is too short, the content may be identified, so for example, 6 fields (about io.

rIEBJ) or longer. A marker signal is inserted to indicate the above-mentioned 6-field unit, and the marker signal used for scrambling the video signal described above (for example, marker signal S9 in FIG. 5) may be used as this marker signal.

FIG. 15 shows a scrambling circuit for converting Φ shown in FIG. 14 into actual Mu.

BBD with 6 field delay time is ll! A! - The input audio signal is always written and read using a clock synchronized with the VD of the image signal. The read signal and the original audio signal are alternately selected every 12 fields by a switch. This results in 2.4.6 in Figure 14.
......The th signal is taken out as is,
The 1st, 3.5th, . . . th signals are delayed and extracted. Note that the reordering pattern can take the form of inoculation.

(2) Time reversal method (51 (16th) of the video signal scrambling method described above)
This is based on substantially the same idea as in Figure 15.
As shown in the figure, 6 fields are written into the memory in units of 6 fields, and these are read out continuously in the reverse direction, or in combination in forward and reverse directions according to a predetermined pattern.

Figure M17 shows an embodiment of the scrambling circuit, in which a 6-field memory performs writing in the up direction and reads out in the down direction using an up/down counter. The read signal and the original signal are selected by a switch and output. The switching of this switch is performed at a timing corresponding to the scramble pattern shown in FIG.

As described above, according to the present invention, when receiving a scrambled broadcast in which a key signal for descrambling is added to the end of a scrambled program, it is possible to perform 'PALPI' in real time. First, it is possible to ensure that the correct program cannot be viewed unless a Ni'' recording and reproducing device such as a VTR equipped with a decoder is used.

Further, regardless of the type of VTR used, changes to be made to the VTR can be minimized.

[Brief explanation of drawings]

1 and 2 are block diagrams showing an embodiment of the connection relationship between a VTR, a decoder, and a receiver, and FIG. 6 is a diagram showing an embodiment of the signal arrangement of a scrambled broadcast signal according to the present invention.
Fig. 4 is a block diagram showing an embodiment of the Tecoder, Fig. 5 is a waveform diagram showing an embodiment of the scrambling method, Fig. 6 is a block diagram showing an embodiment of the scrambling circuit, and Fig. 7 is a modified example of the scrambling circuit. 8 is a waveform diagram showing a modified example of the scrambling method, FIG. 9 is a diagram of a television screen, FIG. 10 is a block diagram showing a modified example of the scrambling circuit, FIG. 11 is a diagram of a television screen, Figure 12 and 1
3 is a block diagram showing a modified example of the scrambling circuit, FIG. 14 is a time chart showing a modified example of the scrambling method, FIG. 15 is a block diagram showing a modified example of the scrambling circuit, and FIG. 16 is a modified example of the scrambling method. FIG. 17 is a block diagram showing a modification of the scramble circuit. In addition, in the symbols used in the drawings, (1:・・・・・・・・・・・・VTR(2)・
・・・・・・・・・・・・・・・Decoder 8,・・・・・・
......Key discrimination signal S, ......
......Audio signal S, ......
・・・・Key signal S7・・・・・・・・・・・・・・・
It is a video signal. Agent Masaru Ueya Masaru Matsudai Fig. 8 1--/H- Fig. 9 ■ [Shi 1] Fig. 11 389-

Claims (1)

[Claims] Memorize the means for recording and reproducing the scrambled television signal of the specific program and the key signal for descrambling added to the end of the specific program.
and means for descrambling the television signal from the recording and reproducing means based on the key signal read from the upper P memory means when reproducing the upper rudder specific program. Device.