<div class="application article clearfix" id="description">
<p class="printTableText" lang="en">280836 <br><br>
Priority Date(s): - <br><br>
Complota Specification Filed: <br><br>
Class: (6) .*»...V*QAtf.a.l P.3, <br><br>
Publication Date: , 2.4MR-199? <br><br>
P.O. Journal No: IM-J.hh : <br><br>
DUE COPY <br><br>
NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION <br><br>
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"RADIATING H.F. CABLE" <br><br>
WE, ALCATEL AUSTRALIA LIMITED, C-^cH cxjo 00 5 3^ A Company of the State of New South Wales, of 280 Botany Road, Alexandria, New South Wales, 2015, Australia, hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, <br><br>
to be particularly described in and by the following statement: <br><br>
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This invention relates to an arrangement for transmitting, radiating and receiving high-frequency signals, the said arrangement consisting firstly of a radiating high-frequency cable which is connected to a transceiving station and which is subdivided into sections separated from each other, the said sections being arranged in tandem in the axial direction; the said arrangement consisting secondly of a suitable signal cable which is capable of low-loss conduction of high-frequency signals and which is arranged parallel to the sections of the high-frequency cable, the said signal cable being connected with the transceiving station , and in which arrangement the signal cable is connected to each two adjacent sections of the high-frequency cable, in a way suitable for conducting the high-frequency signals, at coupling points arranged at intervals. (Proceedings of the 1 st International Conference on Tunnel Control and Communication, 28th to 30th November 1994, pages 181 to 192). <br><br>
Such arrangements with radiating high-frequency cables - referred to below as "RHF cable" - are used for example within the framework of mobile telephone systems, where a communication link is desired between a fixed station and a mobile station. Railway tunnels are a particular field of application, in which a wireless radio transmission is not possible or is only possible with limitations. Due to the radiating properties, HF energy can be received or coupled by means of suitable aerials at each point of such a RHF cable. However, the HF signals are highly attenuated by this design of the outer conductor. In longer lengths of tunnel, <br><br>
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intermediate repeaters have to be fitted in the RHF cable to ensure perfect reception of HF signals along the entire transmission section. <br><br>
Such repeaters are unnecessary in the well-known arrangement in accordance with the publication "Proceedings ..." mentioned at the beginning. Here the sections of the HF cable are connected at intervals in pairs, actually by inserting electro-optical transducers, to the signal cable which is designed as an optical cable. Repeaters, which ensure satisfactory reception of the HF signals along the two connected sections of the RHF cable, are also housed in the coupling points. This known arrangement requires many component parts in the transmission section and in particular many active components. Damage to the component parts or failure of components leads to a severe malfunction in signal transmission. <br><br>
An object of the present invention is to develop the aforesaid arrangement so that failure of individual components does not have any noticeable effect on the arrangement. <br><br>
According to the invention, there is provided an arrangement for transmitting, radiating and receiving high-frequency signals, the said arrangement consisting firstly of a radiating high-frequency cable which is connected to a transceiving station and which is subdivided into sections separated from each other, the said sections being arranged in tandem in the axial direction; the said arrangement consisting secondly of a suitable signal cable which is capable of low-loss conduction of high-frequency signals and which is arranged parallel to the <br><br>
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sections of the high-frequency cable, the said signal cable being connected with the transceiving station , and in which arrangement the signal cable is connected to each two adjacent sections of the high-frequency cable, in a way suitable for conducting the high-frequency signals, at coupling points arranged at intervals, wherein: <br><br>
a suitable component, equipped with a switching element for receiving and analysing a pilot signal coming from the transceiving station, is electrically connected to each of the two adjacent sections of the high-frequency cable at their ends opposite the coupling points, and two sections of the high-frequency cable connected through the component can then be respectively connected electrically to each other through the switching element when the pilot signal is not received in the component in question through at least one of the connected sections of the high-frequency cable. <br><br>
The HF signals in this arrangement are transmitted with low loss in the signal cable. HF signals coming from the transmitter are applied at the coupling points with variable power in each of the two adjacent sections of the RHF cable so that HF signals of a sufficiently high level can always be received along these sections. The transmission range can be raised considerably in this way without using repeaters, even if there are several coupling points between the RHF cable and the signal cable over the length of the transmission section. By analogy, that all applies as well to a vehicle's HF signals inserted into the RHF cable. In addition the transmission <br><br>
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section's operating capability is checked by the pilot signal and each of the components arranged between two neighbouring sections of the RHF cable. If for some reason a pilot signal can no longer be received via one of the sections of the RHF cable, the component immediately switches the connection through to the neighbouring, still functioning section of the RHF cable, so that the defective section is resupplied with HF signals or can effectively receive and pass on HF signals. The availability of the whole arrangement being used for two-way communication is checked by use of the component. Redundancy by means of a parallel system installation can be dispensed with. In addition, no multipath propagation can occur through the active components until there is a fault. <br><br>
In order that the invention may be readily carried into effect, embodiments thereof will now be described in relation to the accompanying drawings, in which: <br><br>
Fig. 1 shows the arrangement according to the invention in a diagrammatic view. <br><br>
Fig. 2 shows the arrangement according to Fig. 1 in an expanded form, likewise in a diagrammatic view. <br><br>
Figs. 3 shows the detail of the arrangement in enlarged representation. <br><br>
In the arrangement depicted in Fig. 1, which shows one entire transmission section with no details in order to facilitate understanding of the invention, an RHF cable 1 and a signal cable 2 running parallel to the RHF cable are connected to a transceiving station 3 which can be fitted with an aerial 4. The signal cable 2 can <br><br>
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be an optical cable with optical wave guides (optical fibre cable), a coaxial HF cable or even a telephone cable for baseband transmission. In all cases the HF signals are transmitted with low loss over the signal cable 2. When using an optical fibre cable, electro/optical transducers have to be inserted in the coupling points between RHF cable 1 and signal cable 2. This does not apply when using an HF cable or a telephone cable as the signal cable 2. The expression "optical fibre cable 2" is used below instead of the description "signal cable 2", and also in place of the coaxial HF cable. The arrangement overall is designed and laid out for two-way communication. <br><br>
The RHF cable 1 is subdivided into Sections 5 and 6 which each have for example a length of 750 m. The number of sections 6 depends on the length of the tunnel section. One section 5 and at least two sections 6 are installed in the tunnel. The section 5 of the RHF cable 1 is connected directly to the transceiving station 3. Each two sections 6 are connected to the optical fibre cable 2 at the coupling points 7 so that HF signals can be transmitted in both directions. <br><br>
HF signals coming from the transmitter S of the transceiving station 3 are fed from the optical fibre cable 2 into two neighbouring sections 6 of the RHF cable 1 by inserting electro/optical transducers 8 into the coupling points 7. The HF signals can then be received along the two sections 6 by means of a suitable aerial. HF signals fed from a vehicle into the sections 6 are coupled into the optical fibre cable 2 via the transducers 8 in the coupling points 7 and transmitted loss-free from the <br><br>
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optical fibre cable to the receiver E of the transceiving station 3. With a longer length tunnel, a greater number of sections 6 of RHF cable 1 are - as already mentioned - arranged in tandem. The number of coupling points 7 is increased accordingly. <br><br>
At the coupling points 7, a joining piece leading to the transducer 8 is connected for example to an optical waveguide in the optical fibre cable 2. This can be accomplished with connectors or fusible links for example or any other suitable method. The transducer 8 is electrically connected to the sections 6 of the RHF cable 1 terminating in each of the coupling points 7. In principle a separate optical waveguide can be led to each coupling point 7. If an HF cable is used instead of an optical fibre cable 2, then power splitters designed for example as 3dB couplers as well, can be connected at the coupling points 7 via HF connectors to the separated HF cable on the one hand, and the two sections 6 of the RHF cable 1 on the other hand. When using a telephone cable as a signal cable 2 for baseband transmission, frequency converters must be used in the coupling points 7. A portion of the power of the HF signal to be transmitted is decoupled from the HF cable by the power splitter. In all cases, this lay-out of the coupling points 7 is advantageous in that the same power is decoupled at each coupling point. At the beginning of the length, and therefore in the vicinity of the transceiver 3, commensurately little energy is decoupled as at other remote coupling points 7. <br><br>
At the ends of the sections 6 opposite the coupling points 7, components 9 <br><br>
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are inserted between two adjoining sections 6 as well as between the end of the section 5 and the adjoining section 6, the said components 9 each being connected electrically to the two adjoining sections of the RHF cable 1. They are used for monitoring and, if necessary, restoring operating capability of the arrangement. <br><br>
A component 9 has in accordance with the representation in Fig. 3 two receivers E of any kind, at least one analyser A and a switching element 10. In the depicted design example one analyser A is allocated to each receiver E. The receiver E is used for receiving a pilot signal which is continuously inserted by the transmitter S of the transceiving station 3. The receivers can be commercially-available receivers. The outgoing signal of the receiver E is analysed and processed by the analyser A. The analyser A is equipped with a decision gate and a logic circuit. The switching element 10, which can be designed as a mechanical or electronic switch, is open as long as the arrangement is functioning trouble free. The adjacent sections of the RHF cable 1 then are therefore not electrically connected to each other. <br><br>
If the pilot signal in a receiver E of the component 9 fails, that failure is recognised by the associated analyser A. The pilot signal can fail for example with a fault at a coupling point 7 or with damage to one of the sections 5 or 6 of the RHF cable 1. An HF signal can then no longer be transmitted from the corresponding section of the RHF cable 1 and also no HF signal can be passed on. The switching element 10 is then immediately closed by the analyser A so that an electrical <br><br>
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connection is made between the two sections 6 or the two sections 5 and 6 connected to the component 9. The HF signal conducted in the section 5 or 6 still capable of functioning is fed though the switching element in the faulty section. HF signals coupled from a vehicle can then be passed on again in the said defective section. <br><br>
In order to ensure that the level of the HF signal in the section extended through the component 9 is adequate for perfect reception also in the region of the defective section of the RHF cable 1, the amplification factor can be increased, if necessary, by repeaters provided at the coupling points 7 and adjustable by a signal from the component 9 or a signal from the transceiving station 3. With the use of optical fibre cable 2 the repeaters at the coupling points 7 are already available. If an HF cable is used as a signal cable 2, adjustable repeaters should be provided at the coupling points 7. For example, for railway broadcasts or data transmission, the frequencies are usefully selected so that they remain interference-free with an increase in amplification level. <br><br>
The analyser A transmits continuous signals during operation of the p <br><br>
arrangement to the transceiving station 3, in which the operating capability of the arrangement can be monitored by it. A fault in the transmission section is recognised there immediately. If necessary, an alarm signal can also be set off. In this way, early elimination of the fault is ensured. <br><br></p>
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