RU2027317C1 - Tellevision and broadcasting signal transceiving system - Google Patents

Abstract

FIELD: communication engineering. SUBSTANCE: television and broadcasting signal transceiving system has television signal source 1, broadcasting signal USW-FM source 2, frequency-to-amplitude modulation converter 3, first and second tracking units 4 and 9, television distribution cable 5, subscriber units 6.1-6N, television signal receivers 7.1-7.N, rejection filter 8, low-frequency broadcasting signal source 10, broadcasting program receivers 11.1-11.N. EFFECT: improved design. 1 dwg

Description

 The invention relates to communication technology and is intended for the reception and distribution of television and broadcast signals over wired communication lines.

 Known collective television reception systems that provide television signals to a collective antenna common to a group of buildings, and distributing the power of these signals to individual buildings and their entrances using a distribution cable network (Varbansky A.M. Television. M., 1973, p. . 410).

 Such systems provide reception and distribution of signals only in the VHF band and provide for the use of appropriate VHF receivers, which limits the possibility of organizing additional information channels (for example, broadcasting) at lower frequencies using less complex receivers based on these systems.

 Closest to the technical nature of the claimed system is a multi-program broadcasting system on a television distribution network, which is selected as a prototype (Dzyadchik V.Ya. et al. Multi-program wire broadcasting, M .: Communication, 1974, p. 22). This system contains a television signal source and a low-frequency broadcast signal source, connected through an addition device to the input of the distribution cable, along the route of which subscriber connection devices are connected in parallel with which, television and low-frequency broadcast signal receivers are connected to the corresponding outputs.

 A disadvantage of the known system is the inability to increase the number of broadcast programs without increasing the number of used television distribution cables, addition and connection devices, which greatly complicates and increases the cost of the entire system.

 The aim of the invention is to increase the number of broadcast programs transmitted over a single television distribution cable while increasing the reliability of program transmission and ensuring their high quality.

 The drawing shows a functional diagram of the inventive system.

 The system contains a television signal source 1, a VHF-FM broadcast signal source 2, an FM-AM converter 3, a first addition unit 4, a television distribution cable 5, subscriber units 6.1 ... 6.N connections, receivers 7.1 ... 7.N television signals, a barrage filter 8, a second addition unit 9, a source 10 of low-frequency broadcast signals, receivers 11.1 ... 11.N broadcast programs.

 The output of the television broadcasting signal source 1 is connected to one of the inputs of the first addition unit 4, the other input of which via the FM-AM converter 3 is connected to the output of the VHF-FM broadcasting source 2, and the output is connected to the input of the television distribution cable 5, the output of which is connected to the entrance of the barrage filter 8 and through parallel connected subscriber units 6.1 ... 6.N connections with the corresponding receivers 7.1 ... 7.N television signals. The output of the blocking filter 8 is connected to one of the inputs of the second addition unit 9, the output of the low-frequency broadcast signal source 10 is connected to the other input, and its output is connected to the inputs of the multiprogram broadcast receivers 11.1 ... 11.N.

 The system operates as follows.

 From the output of the source 2 VHF-FM broadcast signals to the input of the converter 3 FM-AM receives a range of VHF-FM signals of broadcast programs. In this converter, VHF-FM signals are converted to AM waves of a lower frequency range, while the channel spectrum of each broadcast program is sufficient for high-quality broadcasting (for example, first class according to GOST 11515-75), and the channel spectrum difference of different broadcast programs is selected sufficient for their subsequent selection in subscriber receivers.

 The signals from the output of the FM-AM converter 3 and the signals from the output of the source 1 of the television signals are mixed using the first addition unit 4 and fed to the input of the distribution television cable 5. Through this cable, the television signals through subscriber units 6.1 ... 6.N get into the corresponding receivers 7.1 ... 7.N of television signals, and the AM signals of broadcast programs through the barrage filter 8 are fed to one of the inputs of the second addition unit 9, while television signals do not pass through the barrage filter. The signals from the source 10 of low-frequency broadcast signals, which are used as a wire broadcast network, are fed to the other input of the addition unit 9. In block 9, addition is the addition of AM signals and low-frequency signals, then the total signal is received by receivers 11.1 ... 11.N of multi-program broadcasting, in which the program is selected using its frequency selection from the total signal.

 As individual nodes of the proposed system can be used known devices. So, for example, FM-AM converter 3 can be implemented by a set of independent converters, each of which can be implemented by converting the FM signals into AM signals using a detuned oscillatory circuit (as in some FM signal detectors) and transferring the AM signal to lower frequency range with a conventional signal mixer. The first addition unit 4 in the simplest case can be performed, as in the prototype, on the basis of inductance and capacitance. For the second addition unit 9, for example, a well-known soft starter device can be used, which provides the addition of three-program broadcast signals. As receivers 11.1 ... 11.N of multiprogram broadcast signals, AM signal receivers with carrier frequencies of 78 and 120 kHz can be used (for example, the Aurora serial three-program broadcast receiver, etc.).

 Using a wire broadcast network as a source of a low-frequency broadcast signal, the subscriber lines of which are laid in the entrances of houses in joint collectors with television cables, allows receiving both low-frequency signals of the first broadcast program and AM signals of other broadcast programs to these receivers. This ensures an increase in the number of broadcast programs received on one cable of a television distribution network (the cable can be symmetrical, as shown in the drawing or coaxial).

 The reliability of the reception of broadcast programs compared to the prototype is increased by reducing the number of identical galvanically isolated channels, as well as in connection with the possibility of receiving a powerful low-frequency signal of the first wire broadcast program without local power supply to the receivers of multiprogram broadcast signals.

 The high quality of the received broadcast programs is ensured by the fact that the signals of these programs are generated and transmitted as AM signals in the inventive system, the carrier frequencies of which are much larger in absolute value than the spectral width of the original modeling broadcast signals. Therefore, these AM signals are relatively narrowband, which allows you to simply filter them (without mutual influences). At the same time, these signals are not limited by the spectrum of their envelopes in the region from the source 2 of the VHF-FM broadcast signals (including it) to the receivers 11.1 ... 11.N of multiprogram broadcast signals. In addition, due to the lack of a powerful low-frequency signal in the distribution television cable 5, the transient interference from this signal to signals of other programs is reduced.

 The combination of collective television reception systems and three-program wire broadcasting can provide a great economic effect, since while maintaining the existing fleet of TPV subscriber receivers, the network of wire broadcasting is significantly simplified (it becomes single-program), therefore, its reliability is increased and operating costs are reduced.

 In addition, the proposed system has no restrictions on further increasing the number of broadcast programs, for example, when using new receivers of six-program broadcasting over telephone pairs (MTWT system, Altair receiver, etc.) with carrier frequencies of AM signals from 150 to 300 kHz.

 These features of the proposed system allow stereo broadcasting, using two monophonic channels of multi-program wire broadcasting to organize one stereo channel.

Claims (1)

 SYSTEM FOR TRANSMISSION AND RECEIVING OF SIGNALS OF TV AND RADIO BROADCASTING PROGRAMS, containing a source of television signals, a source of low-frequency broadcast signals, receivers of broadcasting programs, a first addition unit, a distribution television cable, N receivers of television signals, while the output of the television signal source and the source are connected to the first input of the addition unit of the television signal unit the output of which is connected to the input of the distribution television cable, the output of which is connected to the input of the corresponding subscriber blocks, the output of each of which is connected to the input of the respective television signal receivers, characterized in that, in order to increase the number of broadcast programs, a source of ultra-short-wave frequency-modulated broadcast signals (VHF FM), a block for converting frequency-modulated signals into amplitude modulated signals (FM-AM), a blocking filter, a second addition unit, while the output of the VHF-FM source of broadcast signals is connected to the first input of the second addition unit through a series tionary conversion unit connected FM-AM signals, a first adding unit and the rejection filter, the output of the source of low frequency broadcasts is connected to the second input of the second adding unit, an output of which is connected to the input of the respective receivers of broadcast programs.