DD218514A5 - CENTRAL MESSAGE SYSTEM WITH A DISTRIBUTION ANTENNA SYSTEM - Google Patents

Abstract

The aim and the object of the invention is to make the otherwise for broadcasting and Fernsehuebertragungen serving systems also useful for other purposes, z. As for traffic between individual extensions, for connecting computers or for remote reading of Haushaltszaehlern. The invention is characterized in that a special message transmission chain is provided between the extensions (2) and the main station (1). This also allows for information transmission contrary to the usual main transmission direction of the system and is designed for frequencies outside the actual operating frequency range of the system. By means of this chain certain assemblies of the system are bypassed when using the system for the aforementioned additional applications. It contains directionally coupled summing elements (8 a to 8 n) and summing filters (6 a to 6 n) and is connected to a main line associated summing filter (9) of the main body, which is adapted to separate the operating frequency band of the additional chain. Fig. 1

Description

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Central message system with a district antenna system

Field of application of the invention;

The invention relates to a central communication system with a Beζirksantennensystem. ι

Characteristic of the known technical solutions;

District antenna systems are widely used to power cities, neighborhoods, towns, and other communities with television and FM broadcasts. The district antenna systems consist of one main station and several ones connected by main lines. "The extensions may be connected to the main station in star or chain form. The antennas of the main station are connected via Pernseh- and VHF channel units with broadband summing, 'summarized the useful signals to the main line. The extensions are each equipped with a broadband amplifier whose outputs are connected to a secondary loop amplifier and, in chained systems, to the main line continued from the extension.

The district antenna systems connect buildings and apartments of relatively densely populated areas with each other.

Since, in densely populated localities, the formation of a trunked interconnect network requires significant investment, attempts have been made to exploit the district antenna system for other purposes as well to avoid or reduce re-investment in interconnect expansion. Since the Bezirksantennensysterne are their purpose appropriately according to ⁱ for transmitting the signals of broadcast channels, but mainly of television channels in the direction from the prime to the extensions (hereinafter referred to as the main direction), the different type of treatments are also using 'television channels, in close connection with the television system has been expanded. These include eg the videotex systems operating according to different methods and the coin program system introduced in the USA, whereby the subscribers can choose among the programs of a television central office. ... · ''.

  All the above solutions are similar to each other in that via the district antenna system the other information only in the direction from the main office to the subscriber, i. can be sent in the main direction. The characteristic values of the signal transmission are limited by those of the program transmission system.

At present, no telecommunications system is known in which 'between any two branches of a district antenna system, a further information link can be made without any restrictions, and also, traffic in the opposite direction is not possible over existing district antenna systems.

Object of the invention:

The aim of the invention is the provision of a central information telecommunication system,. in which over the normally constructed district antenna system between any extension and the main office, possibly also between two arbitrary extensions ^ virtually any number and freely usable information connections can be made.

Such a connection can be useful in inhabited areas for a number of reasons, of which - but not exhaustive - only a few should be mentioned: -central control of traffic control systems, interconnection of telemechanical units with each other inenergetic systems, central reading of household meters, expansion of computer connections or making telephone calls without additional investment.

Explanation of the essence of the invention:

The invention is based on the finding that the Verbindungs.netζ a district antenna system for forming an information chain can also be used against the main direction by bypassing certain system units using appropriate summing and directional summators, the operating frequency band of this message transmission or information chain outside the operating frequency band of the district antenna system lies.

Thus, a central message system is provided, which is linked to the district antenna system, according to the invention between the extensions and the. Main station via the district antenna system an information chain in the direction opposite to the usual main direction

is provided with an operating frequency band located outside the band of the district antenna system whose inputs connected to the extensions are coupled via directional summaries and summing filters, bypassing the units involved in signal transmission in the main direction, to the main line summing filter of the main station Summing filter has one of the new (opposite) direction associated output. '

In a preferred embodiment of the system according to the invention, the output of the main line summing filter associated with one of the inputs of one of the above-mentioned additional information points (in which the information is thus transmitted contrary to the otherwise common main traffic direction, which is referred to below as return direction) Frequency converter connected to the other input of the low-level output of a provided for return traffic pilot signal generator is connected, wherein the output of the frequency converter s is connected to one of the inputs of a broadband summing, while the other input of the broadband summing to the high-level output of the for The output is hereby connected to a main directional band amplifier, and between the output of the Pernseh and VHF channel units and the main line summing filter, a broadband summer is provided which has another input which is connected to the output of the main directional band amplifier. , :

The invention also encompasses a lifting point which, in addition to the units belonging to the extension of the district antenna system, also comprises a directionally coupled summing element. holds whose input is connected to the output of the modulator. The output of the modulator is at the input

one between a main line receiving input and the main directional broadband amplifier switched summing filter, and the output of the main direction broadband amplifier is connected via a further side branch amplifier to the inputs of demodulators.

In one embodiment of the extensions, a second summing filter is used, whose input is at the output of the main directional broadband amplifier and whose output is at a further input of the directionally coupled summing element, its common branch being connected to the outgoing main line. -

Ausführungsbeispielt

The central message system according to the invention is explained in more detail below using an embodiment. The accompanying drawing shows the general block diagram of the system according to the invention.

The central message system according to the invention is linked to a district antenna system. The district antenna system has a main station 1 to which main lines 3a; 3c; 3n extensions 2a; 2 B; 2n are connected. About the extension 2a is another extension 2b. connected to the main office 1, so that the extensions 2a to.2n can be connected to the main station 1 in a star or chain. , ,

In the main station 1 television and VHF channel units 14 are provided, whose inputs are located on antennas 21 and their outputs to a broadband summer 12a. Between the main lines 3a to 3n and the broadband summer 12a, a main line summing filter 9 is provided, the outputs of which for a below the operating. · Lower frequency band of the district antenna system

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Frequency band (4 to 25 MHz) are permeable, with a frequency converter 10 in connection.

A so-called reverse traffic pilot signal generator 11 has a low-level and a high-level output. The low-level output is at the input of the frequency converter 10, the high-level one at one of the inputs of a second broadband summing element 12b. The other input to the wideband summer 12b is connected to the output of the frequency converter 10, where baseband signals in their transposed form (295 to 320 MHz) occur. The output of the wideband summing element 12b is connected via main directional band amplifier 13 to one of the inputs of the first broadband summing element 12a.

In essence, the branches 2a to 2n have the same structure. Hereinafter the love point 2a is described, in the others, the corresponding letter is added to the reference number of the respective extension.

The main line 3a is connected to a common line of a summing filter 6a. The intended for the high frequencies terminal of the summing filter 6a., Is the input of a main direction broadband amplifier 4a and the other, provided for the lower frequencies terminal is located at the output of a reverse traffic amplifier 5a.

The output of the main directional amplifier 4a has three Ab-. two conditions. The first is via a lifting branch amplifier 7a to the subscriber lines, the second outgoing at a Summierfilter 6ap main line 3b and the third over a Uebenzweigverstärker Ta ₂ to demodulators I6a ^, ♦ i6ao · 1.6a. ,,,

In the Pig. The lines for transmitting the signals of the normal operating system of the district antenna system are shown in solid lines, the lines for transmission of the lower frequency band are shown in dashed lines. The signals of the lower frequency band which arrive at the extension 2a via the main line 3b are forwarded by the summing filter 6a ₂ to a directionally coupled summing element 8a. The extension 2a is equipped with modulators 15a ..., 1 5a ₂ ... 15a whose outputs are also connected to the inputs of the directionally coupled summing 8a. The output of the directional. Coupled summing 8a is connected via the back ν er Ae ^ r * amplifier 5s to the low-frequency input of the summing 6a ...

As can be seen, the signals of the operating band and the low frequency band at extension 2a have opposite directions of travel and continue their paths via separate units. To the extension 2a, the message system via baseband signal inputs 17a,. , 17a _o ... 17a and baseband signal outputs 18a., 18a ₂ ... 18a.

The main line summing filter 9, the summing filters 6a. 6a_ and the summing filters 6a ₂ ... 6a ₂ are preferably designed as branching filters, which have separate connections for the individual operating bands and a common connection for both bands.

The central message system according to the invention operates as follows:. .

First, it is assumed that in the vicinity of the extension 2n computer is connected, at whose inputs the basic signal outputs 18η .., 18η "... 1Sn. and whose outputs are connected to the basic signal inputs 17n ^, 17n ₂ ... 17n.

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To substation 2b is e.g. a Verkehrsampelsysteni connected, which is to be brought into interlinkage with the computer connected to the extension 2n. When connecting, the following circuit results:

in the baseband signal input 17 ^ the information output of the traffic signal system is coupled with falling in the baseband TTL signals. These signals are passed to modulator 15b .. where they modulate a carrier in the baseband range of 4 to 25 15Hz by any modulation technique (ASK, PSK, PSK, MSK, etc.). The modulated carrier passes via the directionally coupled summing 8b to the reverse traffic amplifier 5b, where it is amplified to the appropriate level. The return traffic signals are then input via the summing filter 6b .. into the main line 3b. , '

About the main cable, the signals go to the summing filter 6ap the extension 2a, from there via the directionally coupled. Summing 8a, the amplifier 5a and the summing filter 6a .. to the main line cable 3a. The return traffic signals then reach the main station 1 via the main line cable 3 a. ·.

The return traffic signals arrive via the main line summing filter 9 to the frequency converter 10. In the frequency converter

10, the signals are mixed with the signal of the reverse-traffic pilot signal generator iH, and then signals appear in the output in the frequency range of 295 to 3201 SiHZ, this signal then reaches the broadband summer 12b.

The broadband summer 12b also receives the signal of the return traffic pilot signal generator 11 with such an amplitude that at the output of the broadband summer 12b, the amplitude of the reverse traffic pilot signal generators

11 by 11 dB higher than that in the frequency range of

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295 'to 320 MHz falling return traffic signal is (this is generally true for all Rückverlaehrssignale).

Such a transmission of the signals of the return traffic pilot signal generator 11 and the return traffic information is required for the subsequent demodulation, since then the signal of the return traffic pilot signal generator 11 is used as a local oscillator signal.

From the output of the broadband summer 12b the signal reaches the main directional band amplifier 13 whose output is connected to the outputs of the television and VHF channel units 14 via the broadband summer 12a. , ''

At the output of the broadband summer 12a thus the signals of the Pernseh and VHF channels, the return traffic pilot signal and the mixed return traffic information from 295 to 320 MHz occur. This summed frequency spectrum passes through the main direction summing filter 9 and the main line 3n to the summing filter Sn ^ of the extension 2n. The summing filter δη. is designed to pass the frequencies of 40 to 320 MHz only for the main direction broadband amplifier 4n.

The output of the main direction broadband amplifier 4n has. three outlines, ie the output has three branches. Sound of the first branch, the signals pass through the summing filter 6n ₂ to the next extension.

The other two outputs or branches of the main direction broadband amplifier are connected to sub-branch amplifiers 7n ^ and 7n ^, of which the line branch amplifier 7n ^. the signals of the television and VHF channels are forwarded to the subscribers, while the lifting branch amplifier 7np serves to forward the return traffic information.

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From iTebenzweigverstärker 7n ₂ , the signals reach the demodulators 16η .., I6n ₂ ... ¹ ^ ^η _η · These demodulator en consist of.zwei parts. The first one serves * to transpose the frequency range from 295 to 320 MHz into the range from 4 to 25 MHz with the help of the reverse traffic pilot signal. This mixture with the return traffic pilot signal at the main station and in the demodulator allows for greater variations in the frequency of the reverse traffic pilot signal and eliminates the need for an additional oscillator in the first part of the "demodulator." The second part of the demodulator generates the liodulation operation of the reverse traffic signal TTI baseband signals.

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If, for example, the second part of the demodulator 16... Is designed to receive the signal of the modulator 15 b., The detailed image of the input via the baseband signal input 17 b .. TTL signal appears at the baseband signal output 1Sn ₁ , wherein between the two signals only one the difference which has an effect on the delay corresponding to the maturities of the said elements is

The information output by the traffic light system located at the lifting station 2b thus reaches the input of the computer provided at the extension 2n via the main station, which can evaluate this information in accordance with its program. He may make irregularities on the basis of the information received. If the traffic light system is fixed, it can issue appropriate instructions via the route over which the announced signal transmission took place. ,

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One possible signal path may, for example, on the baseband signal input 17n _2, the modulator 15 ^, "the direction coupled summing 8n, the reverse traffic _amplifier; 5n ,. the Summierfilter 6n.j, the main line 3n, that Hauptricht'ungs-Summierfilter 9, the frequency converter 10, the broadband

Summing section 12b, main directional band amplifier 13, wideband summer 12a, main-direction summing filter, main line 3a, summing filter 6a, main-direction broadband amplifier 4a, summing filter 6 & 2 as main line cable 3b, summing filter 6b, main-direction wideband amplifier .4b, the lift arm amplifier 7b ₂ and the demodulators I6b ₂ ... 16b. run. However, if the demodulator ¹ I6b _{2 is} ready to receive the signal of the modulator 15n _2, the TTL signal input via the baseband signal input 17n ₂ is obtained at the baseband signal output I8b ₂ .

It will be understood from the foregoing that in a purpose constructed district antenna system, besides the television and FM signals, various other types of information may be transmitted, and that connections may be made in either direction between any two points of the district antenna system via the main site.

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Claims (1)

, .... ^; - 12 - · ". · ·, Claim for: 1. Central message system with a district antenna system, wherein in the district's antenna system ^l a central main station is provided, are connected to the output via main lines extensions and 'the main body Pernseh- and'UKW channel units with a J at their outputs lying broadband summing and has wherein in each extension a main direction broadband amplifier is provided, whose output L 'connected to a secondary arm amplifier and can be connected to an outgoing from the substation main line, characterized in that between the branches   '. (2a to 2n) and the main station (1) via the district antenna system, a wired communication chain, which allows an information transmission against the main direction, is provided, the operating band is outside the working frequency range of the district antenna system, that to the extensions (2a «''. · To 2n) connected inputs of the aforementioned message transmission chain via directionally coupled summing elements (8a to 8n) and summing filters (6a to Sn) , _r - ~:. those at the signal transmission in the main direction ^K - · 'involved units of the respective branch bypass, with a main rsummierfilter (9) of the main office (1) are connected, and that the main line summation filter (9) has an output associated with the message transmission chain and for " operating band separation of the message transmission chain suitable is. »,, , 2. Central communication system according to item 1, gekennzeich- \ - 'net characterized in that in the main body (1) of the post- , News transmission chain. associated output of the main, line summation filter (9) mit.einem the inputs of a frequency converter (10) is connected, at the other input of the low-level output of a - 13 -. ' connected to the traffic in the main direction opposite direction pilot signal generator (11) is connected, that the output of the Frequenzwandler- (10) with one of the inputs of a broadband summing (12b) is in communication, while the other input of the broadband summing (12b) on high-level output of the aforementioned pilot signal generator (11) is located, and that the output of the latter summing is connected to a main directional band amplifier (13), wherein the broadband summing (12a) between the outputs of Pernseh- and TJKW channel unit en and the input of the main line summing filter (9) and having another input connected to the output of the main direction band amplifier (13). Central message system according to item!, Characterized in that in a lifting position, the one connected to the main line of the main entrance, a main direction broadband amplifier (6a .. ... 6a) connected to this input and a lifting branch input amplifier connected to its output (4a 4n), a directionally coupled summing element (8a to 8n) is provided, whose input is connected to the output of one or more modulators O5äj to 15a _n ), that the output of the modulator or ,, the modulators (14a to 15a _n ) at the entrance of an intermediate is located on the main line input and. the main direction broadband amplifier (4a to 4n) arranged summing filter (6a .. to 6η ..), and that the output of the main direction broadband amplifier (4a to 4n) via another üebenzweigverstärker (7a2 to Tn ^) is connected to demodulator inputs (16a to 16a "). - 14 - Central communication system characterized according to item 3> that the extension comprises a second Summierfilter _{(6a? 6n?)} Whose Singang is located at the output of the main-directional wide-band amplifier (4), while the output (to a further input of the directional coupler summing 8a- 8n) and whose common branch is connected to the further main line (3b). - For this 1 sheet drawing -