JPS6098786A - Scramble method in pay television system - Google Patents

Abstract

PURPOSE:To accelerate a subscriber's poling speed by encoding reserved information and channel information and by inserting it within a period of blanking. CONSTITUTION:Terminals 1 and 2 are inputted by input and output trminals and scramble data are inputted from a terminal 27. By scrambling a signal within the blanking period during television signaling by an integral-fold pulse of horizontal frequency in order to allow the signal not to descramble, the method is devised to prevent deterioration of a printed image. Furthermore, reserved information and channel information are encoded by a code which is correlated with said pulse and inserted into a blanking period, which allows obtaining only data whose program is selected, thereby permitting acceleration of each subscriber's poling speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a scrambling method in a pay television system.

(Conventional technology) It is desired that pay television systems in the United States and other countries be operated with a system that allows charges to be set for each channel or program. Normal reception equipment does not receive signals normally, but only certain subscribers (those who are willing to pay to watch the program) need to take measures to return the signal to normal.

Conventional scrambling methods include simply reversing the polarity of the video signal or manipulating the synchronization signal, but if it is simply scrambled, it can be easily manipulated by the receiver. There is a possibility that the second message will be received,
On the other hand, if complicated scrambling is applied, the descrambling (returning to the original video signal) on the receiving side will not only become cumbersome.

A problem arises in that image deterioration occurs.

In view of these points, the synchronization signal, etc. during the blanking period of the television signal is converted to horizontal li! A method of scrambling pulses with an integral multiple of the number of slopes has already been proposed in Japanese Patent Application No. 58-26485.

- In the conventional pay TV system, broadcasting stations sent program reservation information and channel information to broadcast channels and @groups through seven data-only channels.

However, with T, the amount of data increases and the polling speed (the speed at which individual data is sent to each subscriber) slows down, and even when a channel is selected, program information for that channel is not available. OBJECTS OF THE INVENTION The object of the present invention is to overcome the above-mentioned disadvantages and to provide a complete scrambling system for a Pay TV system. .

(a) Accomplishment of the Invention The scrambling method of the present invention scrambles the signal in the blanking period of a television signal with a pulse having an integer multiple of the horizontal frequency. coded with a code that correlates with the pulse.
mF inserted within the blanking period and characterized by T here; 1. It is.

Embodiment In the following embodiment, the vertical blanking period C2 of the channel information and reservation information of the television signal is inserted and the mode will be explained using an example C1.

In Fig. 1, (a) is a video signal that shows the vertical blanking period (VB)' and the center of the odd field, with a few signals before and after it, (Pl) is a horizontal synchronizing pulse, and (Pl) is a horizontal synchronizing pulse, (Sl ) is the video signal, (S2) is the color burst, (P5) is the vertical sync pulse divided by the OI# pulse (P2), and (P4) is the vertical sync pulse period (vp) after nil. This is a π equalization pulse provided only within the equalization pulse period (BP) (EP) corresponding to each 5H. In addition, in Figure 1 (at 1.2...
The number 21 indicates the line number.

FIG. 1 (bl is the scrambled TV video signal shown in FIG. Instead of the pulse (P4) or the vertical synchronizing pulse (P3), a pulse (P
5) Insert 'i' and add Fleming Coat (F) 'Yroke%ft?' to 1... of the pulse train. It's in. This Fleming code (Fl is 184T from the beginning of the first line)
8 after a period of pulse train group of c(Tc=-4fH-0,9950557μ8)
After the pulse train group of 184 TC, a second Fleming code is inserted for 8 To periods (2), followed by <28 Ta period channel information (
°156 Tc after Q) (188 for odd field times)
C: 511 after pulse train group of To (at even field)
The 11th Fleming code is inserted over and over again in the gTc period. The content of this Fleming code (F) is the same both in the first and second (B) and C26th occurrences, and it is assumed that it includes the content of scrambling in the television signal of the program. Fleming code (F) is 1l17 (C)
This is a code formed of 28 pits, and in the case of FIG. The first and fifth Fleming codes are continuous (double-coupled) with a 64fH pulse (P5) before and after that,
The second Fleming code has a 64fH pulse (
P5) and the channel information (Q) at the rear end.

As shown in FIG. 1(d), the channel information is encoded with a code (in the case shown, the same code) that correlates with the pulse of (54f'H) as an fniscramble signal, similar to the Fleming code CF).

Encoding channel information using such a correlation code is Noodle 1.
Scrambling on the transmitting side and descrambling on the receiving side are easy (produces the effect of double T).Channel information includes program identification data and scramble content (whether the video is inverted or not). The program consists of T scrambled data indicating whether the program is an adult program or not, but it is also possible to insert T data indicating whether the program is an adult program or not.

Vertical synchronization pulse period (VPJ) and equalization pulse period (EPJ)
) as mentioned above with a 64fH pulse? By inserting and deleting the vertical brightening pulse (P3) and equalization pulse (P4), vertical synchronization will not occur even if received by a normal TV receiver on the receiving side C2, and a normal screen will be displayed. Not played. In order to further ensure scrambling, it is preferable to use a method of shifting the video signal portion (Sl) 'a' by a constant value T which exists outside the period from the [gamma]th line to the 21st line by a constant value T from the clamp level.

Figure 2 shows how such a video signal portion (Sl) is shifted by a constant value T. In Figure 2, a normal video signal is used, (Pl) is a horizontal synchronizing pulse, and (S2) is a horizontal synchronizing pulse. Color burst, (L) is the pedestal level, (Sl) is the video signal part T0 What is (11) in Figure 2? This shows the case where the video signal portion (Sl)'Y-Bo is turned downward by a certain value in a normal video signal. This shift amount is, for example, 7 from the pedestal level (L) to the white peak level.
0 and horizontal synchronization pulse (Pl) from the pedestal level.
If we take -50 to the tip of , then half of the above 70! 1
Assume that it takes only 5 minutes. If you do this, the brightness will not only change compared to the normal case, but also the average rx DC level of the video signal will drop, making it difficult for the receiver to separate the horizontal synchronization pulses, and horizontal synchronization will not occur. be. This is because the horizontal synchronizing pulse is detected on the receiver side by determining whether or not it protrudes below the average DC level of the video signal by a certain value.

In addition, in order to actively scramble the Nibo flat synchronization (C1), a 64 fH pulse (P5) is also inserted in the Nibo flat synchronization pulse (Pl) part. In this case, the pulse The average level of (P5) is the pedestal level (L) (2 approximately coincident with the pulse (
The amplitude of P5) may be increased as shown by the dotted line (P5), but considering that the horizontal synchronizing pulse is generally separated by the amplitude of the horizontal synchronizing pulse on the receiver side.

It is preferable to make it smaller by 6 as shown by the solid line (P5). The second factor 1111+ shows the case where the video signal portion ts+)y is inverted by a constant value as shown by the symbol T in the figure, and the video signal portion ts+)y is inverted. The scrambling effect is produced simply by reversing the portion (Sl). However, it is well known that the video signal portion (Sl) is simply inverted.

In addition, unlike the method of inserting a 4fH pulse instead of the horizontal synchronizing pulse (Pl), as shown in 7J-451g II (fH-250Hz), a sine wave with a frequency different from fH (W) may be used to replace the horizontal synchronizing pulse (PI).In this way, the % pre-station sine wave (W
) are sequentially out of phase and large.

Normal horizontal synchronization is not possible at the receiver (11+l2).

Therefore, horizontal synchronization scrambling can also be achieved in this manner.

Next, when taking a method of shifting the video signal part by a constant value as shown in Figure 1, the virtual video credit/portion of each line from the 10th line to the 21st line shown in Figure 1A+ is calculated. There is no video signal on the line, but it corresponds to the video signal part of the line other than the vertical blanking period (VB), and it corresponds to 1 question per gram of each bohira set meal. It is more advantageous in terms of the circuit configuration of the transmitter 4111 to add the measure of shifting by a constant value.

However, if you only shift to 2 wheels, there will be many wide negative direction pulses (or one very (two long pulses)).
Therefore, there is a possibility that vertical synchronization may occur in this part. Therefore, in that case, a pulse (P5) of 64 fH is inserted in these 10th to 21st lines.

The color burst should be left as is.

@Figure 4 (β) is /) What is the state of scrambling of each line from the 410th line to the 21st line i2? In the case of J Kametsune [
(P5) is the 64f
The average DC level is approximately the same as the pedestal level (L). Therefore, this part is received R
The fact that it is detected as a pseudo vertical pulse at m+ and vertical synchronization is applied means that r(i.

4th-(β) horizontal synchronizing pulse part [jth 5132; l
Needless to say, 1, C2, and τ are also good.

In the case of an even field, a pulse of C64fH is inserted across the entire virtual video signal portion of the 21st line, but in the case of an odd field, the virtual video signal of the 21st line is inserted as shown in Figure 51 (al). In the latter half of the part, the ferric acid signal (Sl) actually consists of 1, so % 1 Factor 1b
For the 21st line, as shown in FIG.

As I said earlier, the line f where the color burst exists
Regarding the second point, regardless of whether it is a vertical blanking period or any other period, the color burst remains as it is and is not scrambled. This is because it is difficult to descramble, and when descrambling, the frequency of f28.58 MHz collapses, causing deterioration of the reproduced image.

Next, the TV signal 1W is scrambled and the output is sent to CATV.
An example of the circuit on the broadcasting station side will be explained according to FIGS. 5 and 6,
Next, an example of a circuit on the receiver side for descrambling the scrambled television signal will be explained with reference to FIGS. 7 and 8.

First, in Fig. 5, the input terminal +l+ is connected to the input terminal 1a in Fig. 1.
The l and lal signals are input to the transformer for each field, and the output terminal (2) outputs @1 Figure 1bl and (bl signals to the transformer accordingly.
Hereafter, Fig. 1 (al is the input signal, Fig. 1 (bl
The output signal is T. In FIG. 5, +31 is a buffer amplifier, and (4) is a first clamp circuit for clamping the level of the input video signal. +51 is a synchronization separation circuit, which separates the input video signal (al) from a composite synchronization signal (1
) outputs down. (6) is the horizontal synchronizing pulse (
This is a pulse generator that outputs a first pulse with a slightly wider width than the horizontal synchronizing pulse (Pl) synchronized with Pl), and outputs a second pulse to line +81 covering the first to ninth lines. (9) is a deletion circuit that operates to remove one horizontal phase pulse produced by the first pulse of the pulse generator 16) from the video signal given from the first clamp circuit (4).This deletion circuit The output of (9) is shown in Figure 6 ((2
) is shown. 11 (branch) is a blanking circuit,
The second pulse applied from the pulse generator (6) also blanks the first to ninth lines in the video signal. Therefore, the output of the blanking circuit Ou becomes the sixth meat level. What is in charge is a level shift circuit that operates to leave the color burst and a small portion before and after the output 1 and lower the other portion by a certain value, and its output is branched into two by lines (12+ and 1131). -1 is connected to the gate circuit (171) through the second clamp circuit (14) 2.
The other one is added to the gate circuit (+71) through the inverting circuit a9 and the third clamp circuit LI61.The second clamp circuit (14+ and the fifth clamp circuit aω σ9 is the composite sync signal given from the sync separation circuit (51) and the 64fH This is a phase comparator that compares the output phases of the voltage controlled oscillator (2) and uses the difference signal to form the Lth PLL circuit that controls the stain pressure control oscillator (2).

Note that the equalization pulse (P4) in the composite synchronization signal has a frequency of 2fH, which is different from fH.
Since it is not favorable for LL operation, the equalized pulse is removed by the pulse from the pulse generator CD of @2 in the phase comparator α9. The second pulse generator (211 to the timing pulse generator (27Jζ2) is synchronized with the horizontal synchronizing pulse (Pl) and is supplied with a pulse of the T square mantissa fH. The timing pulse generator (221 is ¥J6 Figure 1ffil!
2311' - 64fH which is separately supplied from the voltage controlled oscillator 0α. The pulse is output only during the pulse period.

Therefore, the output of the second gate is as shown in Figure 6). Timing pulse generator (second output of 221)
is applied to the third gate I251. Mode switching Sui Sochi V! (A) is the dragon suppression sub-oscillator CO1 to 64f.
From H's pulse and sine wave oscillator (3) (fH-250
A sine wave with a width wave number of Hz) is given, but only one of the sine waves is output as scrambled data and supplied to the fifth gate C9. The sixth gate is a timing pulse generating circuit (corresponding to the second pulse period (horizontal synchronization except for a part) ζ pulse period C2 given from 27J). (241
Allows signals from to pass through. The selection of the mode changeover switch is performed by one bit of the 15-bit scramble data input by the scramble data input terminal (shift). This scramble date is latched by the latch circuit (281).

The third output pulse of the timing pulse generator (221) is supplied to the fourth gate eJ91, and this fourth gate (29) is connected to the 8 pin Fleming gate (2) from the latch circuit (2). The Fleming code is applied through an 8-bit switch that allows only the 4th gate +:a to pass.
It is output only during the pulse period of .

The fourth output pulse υ- of the timing pulse generator a21 is applied to the @5 gate (58), and this fifth gate (58) is connected to a voltage controlled oscillator (64 fH of 2 distortion).
A pulse of 64 fH is outputted according to the code signal and a T code signal representing the channel information 7 given through the latch circuit (281) from the scramble data input terminal (see FIG. 6). .The second
, 5th, 4th, 5th gate +231G! 51CI! 91
The outputs of (5B) are all given to the gate (17) and output from the timing pulse generation circuit (1 gate a7 in accordance with the order of the timing pulses from 2z). At this time, the gate N+7) outputs only 10,000 of the video signals from the second and third clamp circuits 141σe in accordance with the 5-bit data from the latch circuit (A). In this case, the second and third clamp circuits (141
It is possible to alternately output the video signals from the 110 field by field, or to alternately output them according to a random rule. C: The 6-bit data is selected so that the video signal of the 3-clamp circuit is output all the time. Therefore, when there are two programs consisting of f, the video signal part (Sl) is inverted and the video signal is transmitted, while for other programs (two and one are inverted and rj is <%
! It is assumed that the message will be sent. Zero slip is output amplification [four-way. Scramble data input terminal 1 in tB5 diagram
The scrambled data given to the first C output is mixed with the channel information separately output from the fifth game 4 (58) and transmitted, and is decoded by the decoder of the reservation terminal 4111+.

Next, the circuit of the T receiver (11+1) shown in FIG. 7 will be explained.

A scrambled video signal such as the one shown in FIG. 1 (31) is input to the input terminal (to).
32 is a DC clamp circuit, (33) is a Fleming code (representing Fl, and since the amplitude of the T pulse changes during transmission, it is a slicer to make the amplitude equal to a constant value f2. -) is /) It is a 4fH filter, /)4fH
The signal (351 has a certain degree of sustainability).The video signal is removed by this filter. Detector 0!51 detects (11) due to two factors and 64fH pulse train of the horizontal synchronizing pulse (Pl) period and 64 of the 10th line to the 2nd line in Figure 1+bl.
For the fH pulse train, the predetermined value T is 7Ijr:
@It doesn't happen, but 64f from the 1st line to the 9th line
H pulse train 1: On the other hand, there are many 64 f H pulses T
exceeds a predetermined value. 8th C [(11) is
The situation in this case is shown below, and by charging with a 64 fH pulse, the output is increased to a predetermined level (El
)'i exceed. In this way, the flexible line test 'lH7D C(5
! The output of l! When the Ii constant level (El)f is exceeded, the V gate flip of the first stage becomes 1llf1<. According to the vI operation C2 of the seventh V gate Dil, the R-S flip-flop βn is the 81st
The signal changes to high level as shown in image fll11. +33) is A
The output of the R-S flip-prop C (71) is a high-level light 111b. F)”r detection 1
- Lugoto (two-purpose power path (40 pulses IPJ8 figure (lv
Occurs like + -[ru. In addition, the Fleming hood detector C
In a1f2, the pulse of 64fH from the filter l341 is given as a clock pulse for the shift register couplet. The pulse (, 8th [1tlv+]) output from the Fleming code detector Q1 is 5 rj4" counter (
It is counted in 1). The output of the hexadecimal counter (8th l': 1tVl) is applied to the reset terminal of the RS flip-flop and the reset terminal of the RS flip-flop is +J[I, so the RS flip-flop (' i
The output of 71 drops from high level to low level. Therefore.

After that, no signal is output from the AND gate a.

(42 is a voltage dividing oscillator with a frequency of 64fH provided on the receiver side, and a phase comparator that compares the phase of the 64fH pulse supplied from the filter with the output of the oscillator (421). +43 is controlled in a PLL format by the output of oscillator C2. Descend.The scrambled video signal is given to the input terminal reserve [1st
In Figure (b1), the video signal has been shifted one step and is returned to its original state by the shift circuit.

The pulse given from the output path (counter 144) through the four output paths is a pulse containing a color burst and a small portion before and after it, and the level of the portion other than the pulse period is shifted in the opposite direction from the transmitting side to restore the original Return to level T0f4
91 is a circuit that removes the 64fH pulse, t5
t) is a circuit that is formed by counter 0 (1) and inserts a composite synchronization pulse, and (51) is a switch circuit that passes the output of the circuit mark as it is or inverts it to pass it.
Addressable CPU given through power path (52) y
The node J is determined by the output of (60). (55) is the output of switch (51) and the signal 40 from the input terminal (to).
This is a selector switch that selects and outputs the control f/n signal from the PU (60). (59) is a data decoder that detects the 64fH pulse of the 4z signal from the data given by the AND gate (c), and its output is given to the cps (60).TV signal During the blanking period (double-press and transmitted), program information among the channel information (Ql [see Figure 1 tb + tb5]) is sent to the CPU (60) via a separate reservation data terminal (
A comparison is made to see if it matches the reserved program data inputted from 61, . The reservation data terminal (6
The data given to 1) is transmitted from the transmission 4111 by a data-only channel separately from the television signal, and is received (decoded at 1t!l).

If the comparison outputs are 1 indicating that they match, the changeover switch (55) applies the output from the switch (5]) to the llj input terminal (54Jl-), and if they do not match, 2
In the case shown, the signal from the input terminal is directly applied to the output terminal (54). In the case of after-sound, the scrambled single-frame signal given from between the input terminals is sent to the output terminal (5
4), the image cannot be reproduced on subsequent devices. The reason for providing the structure is to derive the video signal supplied through the line (55) to the output terminal (54).

Although there are cases where a completely unscrambled signal is input to the input terminal (to).

Next, the scrambled data detected by the data decoder (59) is decoded by the CPU (6o), and if the scrambled data indicates that the video signal portion is inverted, it passes through the switch (51). A control signal for inverting the video signal part of the video signal is sent to the switch (51).
) given.

If this is not the case, a control signal is provided that allows the signal to pass through as is. For scrambled data, CPU
No data comparison is performed in (60). In the case of the X example, scrambled data is not transmitted on the data-only channel, and the data input terminal (61)
There is also no scrambled data.

Incidentally, in FIG. 7, the output of i/v is added to the hexadecimal counter (counter 1/4), but this is for determining the start of the counter. Therefore, the counter (44) operates from the a41 Q line of the first field, and
Line doesn't work 1st field only 1st~
No.? The composite sync signal on the line is not regenerated. M1
Is there a pulse between the 1st and 9th lines based on the counter t44? The resulting pulse generator (56) output χ
AND gate (in addition, the passage of the output of filter C34+ is limited to the 1st to 9th lines, and outside of that period, the video signal component element
(This is because there is a possibility that two pseudo pulses will be applied to phase comparator 0.

The output of the pulse generator (56) is added to the clamp circuit C32 + 2, and the σ flow ramp is performed only during that period because the DC clamp row r (
This is because it is the most stable on the dynamic rF.

In the above example, the channel information is inserted into the vertical plank period 7f, but reservation information may be inserted instead of the channel information and the channel information may be sent on a data-only channel.

Alternatively, both channel information and reservation information may be inserted into the vertical blanking period C2 of the television signal.

In this case, f: is the T vertical blanking period (V
In B), a period consisting of a predetermined number of bits is provided after the framing code (F) of the square.

All you have to do is insert the reservation information there.

In addition, when inserting these channel information and reservation information, in Figure 1, after the Fleming code (F), T (there are two people, but after the Fleming code (F), f2/) 4fH
It goes without saying that it may be inserted after the scramble pulse of the scramble pulse.

However, it will be easily understood that in the embodiment, information may be inserted into the vertical blanking period C once and inserted into the vertical blanking period C twice.

(f) Effects of the Invention In the present invention, by scrambling the signal in the blanking period of a television signal with pulses that are an integral multiple of the horizontal Iff number, the receiving side uses a simple trick to scramble the signal so that it cannot be descrambled. In order to prevent deterioration of the pulse, the reservation information and/or the channel information is encoded with a code that correlates with the pulse, and the blanking period C:m is entered, so it can be used separately for data only. Channel kR may not be available, or the amount of information transmitted on the data-only channel is small.
There is the advantage that r<rx, and since the IglT information for the program can only be obtained from the data of the selected group, the polling speed for each subscriber ζ2 is as low as A.

It has the effect of becoming

[Brief explanation of drawings]

The drawings are all related to the uninvented method, and the first figure is a diagram of the signal transmitted by the method of the present invention, and the second figure is a diagram showing the transmission signal according to the method of the present invention. Part 1 and 4 (8)
Is this part of the signal for the first prisoner? This is a detailed explanation of the Shingin Kumikata diagram. Figure 5 shows the main parts of the transmitter side.
The configuration is shown in a circuit diagram, and FIG. 6 shows the signal waveforms to explain it. FIG. 7 shows the configuration of the main part on the receiver side, and FIG. 8 shows the signal waveform of the circuit. (VB)... Vertical blanking period, (P5)...
Pulse of integral multiple of horizontal frequency, (Q)...Channel information. v O< C11M − ++ A) 1＾ ゛te tr'

Claims (1)

[Claims] (1) Scrambling with pulses of an integral multiple of the total horizontal frequency of the signal during the blanking period f2 in the television signal In the scrambling method in the Shitabe 1 television system,
A pay television system C characterized in that reservation information and/or channel information is coded with a food that correlates with the pulse and inserted into the blanking period.
Scramble method in two places.