RU2099899C1 - Device processing television signals in paid tv systems - Google Patents

Abstract

FIELD: radio engineering, devices coding signals in paid TV systems using both cable systems and translation of broadcasts over radio channels. SUBSTANCE: proposed device incorporates coding 1 and decoding 2 units. Coding unit includes control unit 3, inverting unit 4, integrator 5, correction unit 6, extraction unit 7 quantizer 8. Decoding unit includes control unit 9, inverting unit 10, integrator 11, correction unit 12, extraction unit 13, quantizer 14. Input of coding unit is coupled to low-frequency output of videopath of amplifier and its output - to input of videopath of modulator. Input of decoding unit is connected LF output of videopath of PRD and its output - to LF input of videopath of PRM. Capability of multiple increase of coding combinations is achieved due to proper processing of signals which enhances cryptographic stability of system as well as its operational stability under possible instability of radio channel. EFFECT: enhanced cryptographic stability and operational reliability of channels paid television. 1 cl, 9 dwg

Description

 The invention relates to the field of radio engineering, in particular to encoding devices for television signals and, in particular, can be used to encode signals in pay-TV systems transmitted by radio waves or cable.

 Known devices for processing television signals, see, for example, European patent EPO E N 341801 from 01.04.90, cl. H 04 N 7/167. USSR author's certificate N 1663777 from 01.01.80, cl. H 04 N 7/137.

 Known devices include blocks: an analog-to-digital converter (ADC), a block for separating luminance and color signals, a subtracting block, a quantizer, an encoder, a buffer memory unit, a control unit, an adder, an evaluation unit, an allocation module, a divider, a decoder, and a digital-to-analog converter. In known devices, television signals are processed by inversion through a string, which allows for encoding a signal transmitted via cable, thereby eliminating unauthorized access and watching television broadcasts.

 The disadvantage of analogues is that, due to the stringent requirements for the stability of the channel parameters during their technical implementation, they are acceptable only in cable television networks, in addition, these analogues have low cryptographic stability due to the fact that the devices assume inversion as one of the signal processing methods.

 Closest in technical essence to the claimed one is a video signal processing device in a pay-TV network described in Japanese Patent No. 12 B4 [11] class. H O4 N 7/167 621397 from 01/01/91.

 The prototype includes an encoding device and a decoding device. In turn, the encoding device consists of a control device, a switch, a filter key, two reference crystal oscillators, an adder, an inversion module, and a combining circuit.

 The decoding device consists of a control device, a switch, a key, a filter, a reverse inversion module, a combining circuit, and two operational amplifiers.

 With this scheme, the television signal is fed to the device, converted according to the principle of interlace inversion in the SECAM system, and on the receiving side the signal in the decoder undergoes reverse processing.

Thus, it is possible to encode a signal and prevent unauthorized viewing of television programs in a cable network. However, the prototype has disadvantages:
low cryptographic strength, as one encoding method is used;
the device provides stable operation only in cable television systems, since it imposes stringent requirements on the stability of channel parameters.

 The aim of the invention is to develop a device for encoding television signals in pay-TV systems, which has higher cryptographic strength and ensures the operation of the system both in a cable network and in paths using freely propagating waves (radio lines).

 This goal is achieved by the fact that in the known device for processing television signals in pay-TV systems, consisting of encoding and decoding devices, each of which includes control units, inversions and combining the signal, and the inputs of the encoding and decoding devices are connected respectively to the low-frequency (LF) output the video path of the transmitter amplifier (Rx) and the low-frequency output of the video path of the receiver (Rx), correction and highlight blocks are additionally introduced into each of the encoding and decoding devices impulses and quantization.

 In each of the encoding and decoding devices, their inputs are associated with the inputs of the inversion and allocation blocks, and the outputs of the latter with the inputs of the control unit. The outputs of the control unit are connected to the inputs of the quantization unit, and the output of the latter is connected to the first input of the combining unit. The outputs of the inversion units are connected to the inputs of the correction unit, the outputs of which are connected to the second and third inputs of the combining unit. The outputs of the encoding and decoding devices are connected respectively to the low-frequency input of the video path of the PFM modulator and the input of the low-frequency video path of the PFM.

 In addition, if it is necessary to encode sound, additional second inversion and combining units are introduced into each of the encoding and decoding devices, the outputs of the second inversion unit are connected to the first and second inputs of the second combining unit, the third input of which is connected to the additional output of the quantization unit. The input of the second inversion unit in the encoding device is connected to its second input connected to the low-frequency output of the audio section of the transmitting signal. The output of the second block combining the encoding device is connected to its second output associated with the low-frequency input of the audio section of the PRD modulator. The input of the second inversion block of the decoding device is connected to its second input coupled to the low-frequency output of the audio section of the PFP. The output of the second block combining the decoding device is connected to its second output associated with the input of the bass amplifier of the audio section of the PFP.

 The listed set of essential features allows you to significantly increase the cryptographic strength of up to 4096 code combinations in the claimed device), thereby reducing unauthorized access when watching television broadcasts, as well as the ability to transmit encoded television signals not only via cable, but also via radio links.

 The claimed device is illustrated by drawings, on which, are shown: in FIG. 1 is a structural diagram of a device for encoding only a video signal; in FIG. 2 is a structural diagram of a device for encoding a video signal and sound; in FIG. 3 block diagram of the control unit; in FIG. 4 block diagram of the inversion block; in FIG. 5 block diagram of the correction unit; in FIG. 6 is a block diagram of a combining unit; in FIG. 7 is a block diagram of a quantization block; in FIG. 8 is a block diagram of a selection block; in FIG. 9 stress diagrams explaining the operation of devices.

 The television signal processing device in a pay television system shown in FIG. 1, consists of encoding 1 and decoding 2 devices. The video path encoder 1 includes a control unit 3, an inversion unit 4, a combining unit 5, a correction unit 6, an extraction unit 7, a quantization unit 8. A decoding device 2 includes a control unit 9, a video path inversion unit 10, a video path combining unit 11, a correction unit 12 , a clock allocation unit 13, a quantization unit 14.

 The input of the encoding device 1 is connected to the low-frequency output of the video path PRD K1 and is connected to the inputs of the inversion blocks 4 and allocation 7. The outputs of the allocation unit 7 are connected by the first and second inputs of the control unit 3. The outputs of the control unit are connected to the inputs of the quantization unit 8, and the output of the latter is connected to the third input of the video path combining unit 5. The outputs of the inversion unit 4 are connected to two inputs of the correction unit 6, the outputs of which are connected to the first and second inputs of the combining unit 5. The output of the combining unit K2 is connected to the PRD modulator.

 The input of the decoding device 2 is connected about the LF output video path PFP D1. The input D1 is connected to the input of the inversion unit 10 and the input of the allocation unit 13. The outputs of the allocation unit 13 are connected to the first and second inputs of the control unit 9. The outputs of the control unit are connected to the inputs of the quantization unit 14, and the output of the latter is connected to the third input of the video path combining unit 11. The outputs of the inversion unit 10 are connected to two inputs of the correction unit 12, the outputs of which are connected to the first and second inputs of the combining unit 11. The output of the combining unit D2 is connected to the RF amplifier PFP.

 If it is necessary to encode the audio section in the encoding device 1, inversion blocks 15, unions 16 (see FIG. 2) are additionally introduced into the audio section.

 Similarly, inversion block 2 of the audio section 17 and combining 18 are introduced into the decoding unit. In this case, the low-frequency input of the audio section K3 is connected to the input of the second inversion block 15. The outputs of the second inversion block are connected to the first and second inputs of the second combining block 16. To the third input of the second combining block 16 connected an additional output of the quantization unit 8. The output of the combining unit 16 is connected to the second output of the encoder 1 K4, which is connected to the low-frequency input of the audio section of the PRD modulator.

 The input of the second inversion block 17 of the decoding device 2 is connected to its second input associated with the low-frequency input of the audio path PFP D3. The outputs of the second inversion block 17 are connected to the first and second inputs of the audio path combining unit 18. An additional output of the quantization unit 14 of the decoding device 2 is connected to the third input of the second combining unit 18. The output of the combining unit 18 is connected to the second output of the decoding device 2, which is then connected to the bass audio section of the sound amplifier D4.

 Referring to FIG. 1 and 2, blocks 3, 4, 18 can be implemented according to known schemes, for example, as shown in FIG. 3, 4, 8.

 So the control unit (see Fig. 3) can be implemented on the basis of triggers of the known series K155, K561, K555, etc. (Control units 3, 9 in the encoder and decoder are identical).

 In FIG. 4 shows a possible embodiment of the inversion unit, which is made on a separate operational amplifier of the K140 series, etc. (The inversion blocks 4, 15, 10, 17 in the encoder and decoder are identical).

 In FIG. Figure 5 shows a possible embodiment of a correction block on typical operational amplifiers K140 UD, etc. (Correction blocks 6, 12 in the encoder and decoder are identical).

 In FIG. 6 shows a possible embodiment of a unit, combining on typical elements: an OR-NOT circuit, KT315, KT361 transistors, etc. (Combination blocks 5, 11, 16, 18 in the encoder and decoder are made in the same way).

 In FIG. 7 shows a possible embodiment of the quantization unit, which is performed on microcircuits of the known series K155, K561, K555, etc. (The quantization blocks 14, 8 in the encoder and decoder are identical).

In FIG. Figure 8 shows a possible embodiment of a block for selecting clock pulses, which is performed on typical elements. (The allocation blocks 7, 13, in the encoder and decoder are made in the same way.)
The claimed device operates as follows. When a video signal is received at input K1 of the encoder 1 (see FIG. 2), it branches. The first branch is fed to the input of the selection block 7 to create a lowercase and frame sync packages (see Fig. 9, a) that synchronize the system with the input signal. The selected clock pulses are fed to the input of the control unit 3, where the formation of the control sequence occurs (see Fig. 9, b)
The obtained sequence determines the operation of quantizer 8), and he, in turn, gives a command (see Fig. 9, c) from two outputs to the third inputs of the unit of combining the sound path 16 and the image path 5, which determine the sequence of combining the direct and inverse sound and video signals. In FIG. 9, d, d, also shows the control voltage, which characterize the operation of the prototype on the same blocks. From the graphs it can be seen that the prototype has one operating mode, since in it the video signal is inverted strictly through the line. In the claimed device, the inversion of the video signal occurs on the control signal from the control unit 3.

 This allows us to conclude that the prototype is significantly inferior to the claimed device in the number of code combinations. The video signal along the second branch enters the inversion unit 4. In the inversion unit 4, the forward and reverse sequences are formed. Next, the signals from the output of the inversion block 4 pass to the correction block b, where the levels of the forward and reverse signals are balanced and corrected to reduce the amplitude-frequency distortions that occur when processing the signal at low frequencies, in order to provide the possibility of working on radio links and cable. Next, the signals are fed to the combining circuit 5, where there is a code alternation of direct and inverse signals, which are then fed to the input of the modulator PRD K2.

 A sound signal is supplied to the second input of the encoding device l K2, and then it is fed to the input of the inversion unit l5 of the sound path, where the formation of direct and reverse sequences. Then both signals from the output of the inversion block 15 pass to the combining circuit 16, where the code alternation of direct and inverse signals occurs due to the control voltage from the second additional output of the quantization block 8. Next, from the output of the combining block 8, the encoded signal is input to the PRD modulator.

 When you enter the decoder, the encoded signals undergo reverse processing in the same blocks and the output signal is restored.

 Thus, thanks to the introduction of additional blocks, the cryptographic strength is significantly increased in the device (up to 4096 code combinations) and the processed signal is transmitted via radio lines and cable.

Claims (2)

 1. A device for processing television signals in pay-TV systems, consisting of an encoding and decoding device, each of which includes a pulse sequence driver, polarity inversion and video signal combining units, and the inputs of the encoding and decoding devices are connected respectively to the low-frequency output of the video path of the transmitter amplifier and low-frequency the output of the video path of the receiver, characterized in that in the encoding and decoding devices an additional block is introduced and amplitude correction, allocation of clock pulses and quantization, moreover, in each of the encoding and decoding devices, their inputs are connected to the inputs of the polarity inversion blocks and clock pick-ups, and the outputs of the clock extraction block with inputs of the shaper of control sequences of pulses, the outputs of which are connected to the input of the quantization block, and the output of the quantization unit is connected to the third input of the video signal combining unit, the outputs of the polarity inversion unit are connected to the inputs of the amplitude correction unit, the output which are connected to the first and second inputs of the video combining unit, and the outputs of the encoding and decoding devices are connected, respectively, with the low-frequency input of the video path of the transmitter modulator and the low-frequency input of the video path of the receiver.  2. The device according to claim 1, characterized in that in addition to each of the encoding and decoding devices, a second polarity inversion unit and an audio signal combining unit are introduced, and the outputs of the second polarity inversion unit are connected to the first and second inputs of the second audio signal combining unit, the first the input of which is connected to an additional input of the quantization unit, the input of the second polarity inversion unit in the encoding device is connected to its second input associated with the low-frequency output of the audio transmission of the transmitter ka, and the output of the second audio signal combining unit in the encoding device is connected to its second output connected to the low-frequency input of the audio path of the transmitter modulator, the input of the second polarity inversion unit in the decoding device is connected to its second input, connected to the low-frequency output of the receiver's audio path, and the output of the block combining the audio signal in the decoding device is connected to its second output associated with the low-frequency input of the amplifier of the audio path of the receiver.

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