RU68828U1 - DEVICE FOR COLLECTIVE RECEIVING OF TELEVISION TV PROGRAMS - Google Patents

Abstract

A device for the collective reception of television programs of on-air TV refers to television systems and can be used in the design of the headend of a cable television system. It includes two blocks: a block of digital TV signal receivers and a block for amplifying and leveling digital and analog signals of terrestrial TV. The last block is a set of parallel-connected channel filters. The block of digital TV signal receivers contains a number of digital signal demodulators configured to receive a DVB-T standard signal and connected in series with analog modulators, in addition, a number of channel filters are introduced, the outputs of which are connected in parallel with the outputs of the channel filters of the digital gain and level equalization block and analogue signals of terrestrial TV. The device can receive both analog and digital channels of the DVB-T standard in an analog format without the use of additional equipment - subscriber digital set-top boxes. 1 n.a. and 2 z.p. f-ly, 10 ill.

Description

The utility model relates to television systems and can be used in the design of the headend of a cable television system for the collective reception of analog and digital TV signals.

One of the problems of terrestrial broadcasting of the Russian Federation is the transition from an analogue broadcasting format to digital. At the third international scientific and technical conference “Modern television technologies. Status and direction of development ”, held on October 30-31, 2006 at the Moscow Scientific Research Television Institute (CJSC“ MNITI ”) [Scientific and Technical Journal“ 625 ”,“ Digital TV in Russia: Readiness No. 1 ”, No. 10 (124 ), 2006, pp. 72-75] at section No. 1 “Technologies of the 21st Century”, which was chaired by K. N. Bystrushkin, a number of reports on this topic were presented.

It is known that when developing black-and-white, and then color analog television, specialists did not manage to develop a common standard. In the early 1980s, when work began on the creation of digital television broadcasting systems, it became apparent that the future of digital television would largely depend on the creation of a single standard. Professor M.I.Krivosheev M.I. in fact, determined the development strategy of world television for the last quarter of the last century. Under his leadership, digital television systems were developed.

DVB-T, ATSC, HDTB, as well as the principles of constructing interactive television and various information systems based on it. Digital television broadcasting signals should be transmitted in standard bands of 6 MHz (America, Japan), 7 MHz (Western Europe), 8 MHz (USSR, France, Eastern Europe).

The report of M.I. Krivosheev at the named conference was read out by K.N. Bystrushkin. “According to the speaker, at that time, not everyone supported these proposals, since they did not see the ways of their practical implementation. Solution methods appeared only in the early 1990s with the help of the MPEG-2 compression algorithm, which allowed to reduce the digital stream speed of one television program to 4 ... 6 Mbit / s, highly efficient channel modulation methods with an information transfer efficiency of 2 ... 8 bits at 1 Hz of the frequency band of the radio channel.

As a result of the studies, it was proposed to use QPSK modulation in satellite digital television DVB-S, QAM modulation in cable DVB-S television, and COFDM modulation in DVB-T digital terrestrial television (8-VSB channel modulation is used for terrestrial broadcasting in ATSC). These technologies formed the basis of the developed in 1994-1996. a package of standards known in Europe as DVB. Thanks to this, since 1996, the transition to digital broadcasting has begun in the world. ”

At the beginning of this century, a much more efficient MPEG-4 H.264 / AVC compression algorithm was developed, which allowed transmitting in the standard frequency band of digital terrestrial and cable television not 6-8, but 10-12 digital TV programs SDTV. In addition, the new compression algorithm made it possible to transmit several HDTV programs in a standard channel at once. At that time, it was expected that in the next year or two standards for terrestrial (DVB-T2) and cable (DVB-C2) digital broadcasting will be developed.

There is a well-known concept of MNITI for the organization of collective reception of DVB-T in an analog format by analogy with the introduction of UHF broadcasting in the USSR, when these programs were previously converted into a meter wavelength range and were already distributed to the public in this form. Today, 88% of viewers receive live TV shows; 11.5% - on cable TV and only 0.5% have the possibility of direct satellite reception. In turn, 65% of viewers receive broadcast programs through collective distribution networks, and 35% - on their own antennas. The method proposed in the concept of MNITI, at the time of the conference, solved the problem of organizing collective reception of television programs for terrestrial television, however in a general format, and not in specific, purely

technical options [Scientific and technical journal “625” No. 10 (124), “Digital television in Russia: readiness No. 1”, 2006, p. 74, column 2].

The head station AMZ 201 is known [see Telemak product catalog, 2007, p.2, 3, 5-8, 33, 36] of the co-applicant of this application. The headend is designed to form packages of TV channels in the range of 48-862 MHz in cable distribution television networks. The head station includes:

- Active channel filters AMZ 201 01-04 MB and UHF range, as well as active channel filters AMZ 501 01-04M with automatic gain control, which are used for signal levels at the antenna output <10 mV;

- passive channel filters AMZ 201 01-02-03Р with adjustment of the transmission coefficient of the MV range, which are used for signal levels at the antenna output> 10 mV;

- modulators (including with one sideband), including a through channel with low losses at the output and a regulator of the output RF signal level; the carrier image of the modulator MD 605 in MV, SK, HB is formed using controlled dividers;

- analog demodulators designed to convert the broadcast signal of analog television in the range of 48, 25-862 MHz into a full color video signal and sound signal;

- output amplifiers;

- Power supplies;

- directional couplers;

- the chassis on which the elements of the head station are installed;

- cable jumpers, matched loads (CIS1 - for power failure at the output of channel filters, CIS2 - with an injector for powering the antenna amplifiers), power inputs of antenna amplifiers;

- covers.

The head station of the company "IKUSI" is also known [see product catalog "IKUSI", 2005, p. 33, 34, 73, 74]. On page 33, the power supply for the TV head station is illustrated. An output amplifier is also located in the housing of this device. On page 34 the block of active channel filters is shown. On pages 73-74 - demodulators for receiving television channels of terrestrial broadcasting of DVB-T standard.

A device is known [RU patent for the invention No. 2153234] for use in a headend of a cable television system (options) and a method for distributing programs to subscribers in a cable television system.

This device comprises a modular design of the cable headend and a component of the combining device for the headend. The invention can be used in distribution systems for cable television programs that transmit a large number of program signals with digital compression. This unit device allows you to easily make a selection of programs from the transmitted signals, which is the technical result achieved by him. The invention provides: a distribution circuit for digital and analog cable television; a diagram of one cable television headend serving three different cable television systems, each with a different operating frequency band; a diagram of a modular digital cable television system serving two serially connected cable television systems; diagram of the main components of the base head station of digital cable television for the distribution system of digital cable television, as well as the head station with a combining device. Also presented is a diagram of the main components of a digital and analog cable television headend for a combined digital and analog cable television distribution system, as well as a diagram of the main components of an alternative embodiment of the invention for a digital cable television headend with a combining device and remote control access, a diagram of components of alternative options the implementation of the invention for the headend of digital cable television.

The closest analogue to the claimed utility model is the last circuit, see Fig.6 from RU patent for invention No. 2153234, which shows a headend with a digital input and analog output, which uses a combining device that includes decoding devices and analog modulators. The video signal is received in digital form, manipulated, converted and transmitted to the input terminals of the receivers. In this particular design, the video signal is converted from a digital format to an analog format for transmission to input terminals of receivers (in analog form). Using this embodiment of the invention, the advantages of transmitting compressed video signals through satellites can be realized without changing a large fleet of obsolete equipment of the analog input terminals of the receivers.

Radio frequency signals are received by the parent station from a satellite, land line or other means of communication. The shown controlling digital CPU can be remotely controlled or receive specific commands

in place. The control CPU provides demultiplexer commands for identifying a subset of the digital video signals. This subset of video signals is selected by the headend for further processing.

After selecting digital video signals, digital video signals are processed by decoding devices. 6c shows each signal processed by a decoding device. Those skilled in the art will recognize that a wide variety of encoding and decoding methods can be used. After decoding, each analog video signal is processed by an analog modulator prior to transmission to the receiver input terminal (not shown). In this configuration, demultiplexers, decoding devices, and analog modulators can be used. The size of the headend is limited by the available bandwidth for the subscriber’s home. Using the sports program as an example, the work of the cable television headend from a repeater designed for sports programs is shown. The demultiplexer assigned to the sports repeater receives a command to select the desired sports program. Then the sports program is decoded into analog form and processed by an analog modulator. The analog modulator can then place the program in 6 MHz of the available operating frequency band (for example, between 544 MHz and 550 MHz) in a cable system.

This device is not intended for the collective reception of terrestrial analog and digital TV signals, expensive and cumbersome.

The objective of the claimed utility model is to ensure the availability of digital terrestrial TV channels for mass reception.

The essence of the claimed utility model lies in the fact that the device for the collective reception of television programs of terrestrial TV, including a block of digital TV signal receivers, containing a number of digital signal demodulators connected in series with analog modulators, has a block for amplifying and leveling digital and analog signals of terrestrial TV, which represents is a set of parallel-connected channel filters, and a number of channel filters are introduced into the receiver block of digital TV signals, the outputs of which are connected in parallel only with the outputs of the channel filters of the amplification and leveling block of digital and analog signals of terrestrial TV, and each of the digital signal demodulators of the block of digital TV signal receivers is configured to receive a DVB-T signal.

A device is also claimed for collective reception of television programs of on-air TV with the above-mentioned design features, in which the channel filter of the amplification and leveling unit of digital and analog signals of terrestrial TV contains: summation and division circuits installed at its input and output, filtering circuits based on L and C elements, amplifying stages and an adjustable attenuator, moreover, the listed elements are connected in series.

A device for collective reception of television programs of on-air TV is also claimed, comprising an analog modulator of a block of receivers of digital TV signals, which includes a modulating microcircuit, the output of which is tuned to any channel of the TV range, combined with a frequency synthesizer and a controller.

The technical result of the claimed utility model consists in the possibility of receiving both analog and digital signals of the DVB-T standard in an analog format without the use of additional equipment of subscriber digital set-top boxes, which, in turn, makes the reception of digital channels accessible to the general public. The achieved technical result of the claimed utility model is aimed at solving a social problem - the reception of digital channels with minimal population costs. The cost of one set-top box is from 70 to 140 US dollars, while the cost of a collective system for one subscriber is 10-15 US dollars. Due to the configuration of the inventive device, it was possible to obtain a high-quality package of analog and digital signals of terrestrial television broadcasting, as well as signals of digital terrestrial TV transmitted in analog format. Moreover, the inventive system has high flexibility and high performance characteristics that allow you to quickly take into account and respond to regional features of TV broadcasting.

The inventive device is illustrated using figure 1-10, which presents:

figure 1 - scheme of the inventive device;

figure 2 - image of the block amplification and alignment of the signals of the levels of terrestrial TV;

figure 3 - image of a demodulator of digital signals DVB-T;

4 is a block diagram of an active channel filter;

5 is a block diagram of an output broadband amplifier;

6 is a block diagram of a directional coupler;

7 is a block diagram of a divider;

Fig. 8 is a block diagram of a DVB-T digital signal demodulator;

Fig.9 is a block diagram of an analog modulator;

figure 10 is a block diagram of a power supply, in which positions 1-28 are presented:

1 - a block of receivers of digital TV signals;

2 - block amplification and leveling of digital and analog signals of terrestrial TV;

3 - a receiving antenna of on-air TV;

4 - cable reduction from the receiving antenna of on-air TV;

5 - channel filter;

6 - cable jumper;

7 - output broadband amplifier;

8 - directional coupler;

9 - divider;

10 - demodulator of digital signals DVB-T;

11 - analog modulator;

12 - power supply;

13 - power cable;

14 - chain summation (division);

15 - filter chains;

16 - amplification cascades;

17 - adjustable attenuator;

18 - HF ferrite transfluxors;

19 - tuner;

20 - DVB-T decoder;

21 - demultiplexer;

22 - signal processor;

23 - modulating microcircuit;

24 - controller;

25 - surge protector;

26 - rectifier bridge;

27 - power driver;

28 - output filter.

The inventive device for the collective reception of television programs on-air TV contains a block of receivers 1 digital TV signals, block 2 amplification and leveling of digital and analog signals of terrestrial TV. The block of receivers 1 of digital TV signals includes a series of demodulators of digital signals 10 of the DVB-T standard, connected in series with analog modulators 11, a series of channel filters 5. Active channel filters 5, connected to each other and to the output amplifier 7 by cable jumpers 6, contain summing (division) circuits ) 14 at the input and output of active channel filters 5 and are tuned to the frequencies of analog and digital terrestrial TV channels.

The outputs of the channel filters 5 of the receiver unit 1 of digital TV signals are connected in parallel with the outputs of the channel filters 5 of the amplification and leveling block 2 of the digital and analog signals of terrestrial TV.

The input of the output broadband amplifier 7 through a directional coupler 8 and divider 9 is connected to the inputs of the digital signal demodulators 10 of the DVB-T standard, which, in turn, are connected to analog modulators 11, the inputs of which are connected through the cable jumpers 6 to the inputs of the active filters 5 configured on free frequencies in the TV range.

The circuit contains power supplies 12 that power active channel filters 5 through power cables 13.

The drop cable 4 from the receiving antenna 3 of the terrestrial TV is a segment of the standard cable TV connecting the output of the receiving antenna 3 of the terrestrial TV and the input of the gain and leveling unit 2 of the digital and analog signals of terrestrial TV.

The active channel filter 5 contains filter circuits 15 on the concentrated elements L and C (inductance, capacitor), amplifying stages 16, an adjustable attenuator 17, summing (division) chains 14 at the input and output of the active channel filters 5 (Figure 4).

Cable jumpers 6 are pieces of coaxial cable with a wave impedance of 75 Ohms, at the ends of which standard connectors are mounted.

The output broadband amplifier 7 is designed to amplify the signals of the TV range, contains three stages, the last of which is made using a push-pull circuit (push-pull). The circuit of this amplifier is made on high-frequency transistors operating in mode A (linear mode of operation of the amplifier) (Figure 5).

The directional coupler 8 is made on high-frequency ferrite transfluxors 18 and is designed for uneven division in two directions (Fig.6).

The divider 9 - the power divider of the TV range is also made on high-frequency ferrite transfluxors 18 (two-hole ferrites) according to the classical scheme (Fig.7).

Digital signal demodulators 10 of the DVB-T standard are digital demodulators that are designed to extract the audio and video signal of one TV channel from the transport stream of the DVB-T standard. Each consists of a channel selector - tuner 19, which converts the TV channel signal to the intermediate frequency of DVB-T decoder 20, demultiplexer 21 and signal processor 22. (Fig. 8).

The analog modulators 11 of the TV channels include: a modeling chip 23 that generates a signal of the frequency spectrum of the TV range, combined with a frequency synthesizer and a controller 24 for tuning the analog modulator 11 to the desired TV channel and stabilizing the frequency of the analog modulator 11. The main components of the analog modulator 11 have an integral design (Fig.9).

The power supply 12 contains a surge protector 25, a rectifier bridge 26, a power driver 27, an output filter 28 (Figure 10).

The inventive device operates as follows. Digital and analogue signals of terrestrial TV from the receiving antenna 3 of terrestrial terrestrial TV via a drop cable 4 are sent to block 2 for amplification and leveling of digital and analog signals of terrestrial TV, where they are amplified and aligned. In the active channel filter 5, the signal through the division circuit 14 enters the filter circuit 15, where one of the channels of the terrestrial TV is allocated. Then it is amplified by means of amplification stages 16 and is supplied to the output summing element 14. To adjust the gain between the stages of the active channel filters 5, there is an adjustable attenuator 17 that allows you to adjust the level of the output signal over large limits (of the order of 20 dB). After that, the TV channels are fed to the output broadband amplifier 7, which amplifies them to the level necessary for supplying to the network. The output broadband amplifier 7 contains three amplifier stages 16, the last of which is made by a push-pull circuit (push-pull), which is quite widespread in cable TV amplifiers. Through a directional coupler 8 and a divider 9, the signals go to the input of the digital signal demodulators 10 of the DVB-T standard, tuners

19 of which are tuned to the frequencies of digital channels. The radio frequency signal at the intermediate frequency is fed to the DVB-T 20 decoder, where it is converted into a group transport stream of the DVB-T standard, which, in turn, is fed to the demultiplexer 21, which allocates one channel from the group stream in the DVB-T standard. The signal processor 22 converts the DVB-T signal into a conventional analog audio and video format. After the audio and video signals are separated from the DVB-T transport stream, the signals are fed to the inputs of analog modulators 11, which form analog TV channels at free frequencies of the TV range. Low-frequency audio and video signals are fed to the input of the modulating microcircuit 23, at the output of which a high-frequency television signal of the PAL or SECAM standard is formed, which corresponds to the standard OIRT frequency grid. Using the switches on the front panel of the analog modulator 11, any channel of the TV range (48-862 MHz) can be set. To reduce the level of out-of-band interference, signals from analog modulators 11 are fed to active channel filters 5 having summation and division chains 14 at the input and output, which allow summing the packet of received analog signals after modulation with terrestrial broadcast TV signals. Thus, a aligned and amplified packet containing analog and digital signals present on the air, as well as a fully or partially demodulated set of channels transmitted in analog format from DVB-T packets, which can be received by a standard analog TV receiver, is supplied to the TV distribution network.

Claims (3)

1. A device for the collective reception of television programs on-air TV, including a block of digital TV signal receivers, containing a number of digital signal demodulators connected in series with analog modulators, characterized in that it has a block for amplifying and leveling digital and analog signals of terrestrial TV, which is a set channel filters in parallel, and a number of channel filters are introduced into the receiver block of digital TV signals, the outputs of which are connected in parallel with the channel filter outputs s block gain and equalization of digital and analog terrestrial TV signals, and each of the digital signal demodulator digital TV signal receiver unit configured to receive a signal DVB-T standard. 2. A device for collective reception of television programs of on-air TV according to claim 1, characterized in that the channel filter of the amplification and leveling block of digital and analog signals of terrestrial TV contains: summation and division circuits installed at its input and output, filter circuits based on L and C elements, amplifier stages and an adjustable attenuator, moreover, the listed elements are connected in series. 3. The device for collective reception of television programs of on-air TV according to claim 1, characterized in that the analog modulator of the receiver block of digital TV signals includes a modulating chip, the output of which is configured to tune to any channel of the TV range, frequency synthesizer and controller.