EP0747995A2 - Procédé de transmission de données et système d'antenne en particulier pour systèmes de communication de circulation et circuit - Google Patents

Procédé de transmission de données et système d'antenne en particulier pour systèmes de communication de circulation et circuit Download PDF

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Publication number
EP0747995A2
EP0747995A2 EP96810372A EP96810372A EP0747995A2 EP 0747995 A2 EP0747995 A2 EP 0747995A2 EP 96810372 A EP96810372 A EP 96810372A EP 96810372 A EP96810372 A EP 96810372A EP 0747995 A2 EP0747995 A2 EP 0747995A2
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EP
European Patent Office
Prior art keywords
antenna system
as1ae
as1a
as1b
transmission
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP96810372A
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German (de)
English (en)
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EP0747995A3 (fr
Inventor
Alfred Lauper
Max Loder
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens Schweiz AG
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Siemens Schweiz AG
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Filing date
Publication date
Application filed by Siemens Schweiz AG filed Critical Siemens Schweiz AG
Publication of EP0747995A2 publication Critical patent/EP0747995A2/fr
Publication of EP0747995A3 publication Critical patent/EP0747995A3/fr
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/27—Adaptation for use in or on movable bodies
    • H01Q1/32—Adaptation for use in or on road or rail vehicles
    • H01Q1/3208—Adaptation for use in or on road or rail vehicles characterised by the application wherein the antenna is used
    • H01Q1/3225—Cooperation with the rails or the road
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/30—Combinations of separate antenna units operating in different wavebands and connected to a common feeder system

Definitions

  • the present invention relates to a device according to the preamble of patent claim 1.
  • antennas For the transmission of transmission signals with low losses from a transmitter to a receiver, high-quality antennas are used, which form narrow-band resonance circuits that are matched to the transmission frequency. In particular, the source resistance in the transmitter and the load resistance in the receiver are adjusted accordingly.
  • the antennas which act as narrow-band resonance circuits, therefore only allow signals from a narrow frequency range to pass.
  • a larger bandwidth is often required for message channels in which larger amounts of data are to be transmitted. E.g. by damping the resonant circuits, their bandwidths can be increased. However, this also influences the attenuation behavior of the transmission link, so that due to the increase in the bandwidth of the transmission channel, higher signal attenuation must be tolerated at the same time.
  • the permissible transmission powers are limited in particular in the case of traffic communication systems with earthbound and mobile communication units. It can also be assumed that these systems will have an increased bandwidth requirement in the future.
  • the present invention is therefore based on the object of specifying a method for improved transmission of transmission signals of high bandwidth and a corresponding antenna system and a circuit arrangement corresponding thereto.
  • a broadband transmission channel can be created by the antenna system according to the invention, which has only a low attenuation and is suitable for the reliable transmission of larger amounts of data.
  • the antenna system can due to the advantageous transmission characteristics. can be realized in a relatively narrow space, which means that it can be easily assembled, for example, in vehicles. The use of comparatively large broadband antennas is therefore unnecessary.
  • the avoidance of coupling losses according to the invention is of great importance, inter alia, in the remote feeding of traffic communication units whose transmission units have only a low transmission power. This is particularly important for communication units that e.g. only be operated briefly when a vehicle is in transit for the transmission and reception of signals.
  • antennas fulfill the function of transformation quadripoles, which bring about the adaptation between the wave resistance of the antenna feed and the wave resistance of the free space and which convert an electrical vibration transmitted via the antenna feed into an electromagnetic wave.
  • the antenna acts as a resonator.
  • the equivalent circuit diagram of a lossless transmission antenna operated in resonance consists only of its radiation resistance. According to C. Dorf, The electrical engineering handbook, CRC Press Inc., Boca Raton 1993, chapter 36.1, page 864, this radiation resistance for a dipole, which can be determined by calculating the electrical and magnetic fields E, H, is approximately 73 ohms .
  • Aao also describes that the effective length of a dipole can be increased by increasing the end capacitance of the dipole (end loading).
  • FIG. 4 shows an antenna A1, for example, the effective length of which has been increased by the connection of a capacitor Ca1.
  • the wire line which connects the connections of the capacitor Ca1 to one another, therefore acts as an inductor and is schematically referred to as coil La1. It is known that maximum antiphase voltages occur at the ends of the dipole (capacitive zone) and maximum currents occur between these ends in the inductive zone or in the coil La1.
  • their antennas can be coupled, for example, via the magnetic field. In this way, the antenna A1 is coupled to a similar antenna A2 in FIG. 4.
  • a current in the coil Lal therefore causes a magnetic field through which a current is induced in the coil La2 of the antenna A2.
  • the distance d12 between the antennas A1 and A2 is preferably chosen to be smaller than the wavelength of the transmitted signals. This avoids losses that arise if electrical fields have to pass through strongly damping layers.
  • the coils Lal and La2 are formed, for example, by an elongated wire, a coaxial line or a metal strip printed on a printed circuit board. The degree of magnetic coupling can be set by changing the distance d12.
  • the relatively narrow-band pass curves k A1 , k A2 of antennas A1 and A2 are shown in FIG. 5. If a large bandwidth (f1-f2) is required for the data transmission, the antennas A1 and A2, as can be seen in FIG. 5, do not have a sufficiently large bandwidth.
  • the bandwidth of the antenna A2 can be increased by various measures. For example, the quality of the resonance circuit can be reduced by known measures.
  • the coupling of the transmitting and / or receiving stage to the antenna A2 can be adapted accordingly. However, as shown in FIG.
  • a further resonance circuit (antenna A3, consisting of capacitor Ca3 and coil La3) is particularly advantageously coupled to antenna A2.
  • the antennas A2 and A3 form a resonance circuit with a wide bandwidth.
  • the transmission curve k AS23 shown in FIG. 6 of this resonance circuit has two distinct natural frequencies f1, f2, which differ from one another the less the weaker the coupling between the second and third antennas A2, A3.
  • the pass curve k A12 of this vibration system therefore corresponds to that of a bandpass filter.
  • Coupled resonant circuits which are known, for example, from Dobrinski / Krakau / Vogel, Physik für Ingenieure, Teubner Verlag, Stuttgart 1976, 4th edition, chapter 5.1.8.2, pages 316/317, figure 316.1, have so far been used in input or intermediate frequency stages of radio receivers used.
  • the transmit signals emitted by the antenna A1 are therefore received by the antennas A2 and A3 with only slight losses and are emitted to a transmitter / receiver unit.
  • the resulting transmission curve k A123 is therefore determined by the quality of the individual systems and by the degree of mutual coupling or by the choice of the distances d12 and d23 of the antennas A1, A2 and A3.
  • FIGS. 9 and 10 Possibilities for coupling the transmitting and receiving units T / R1, T / R2 or for generating electricity Rectifier units provided to antennas A1, A2, A3 are shown in FIGS. 9 and 10.
  • 9 shows the coupling or the connection of a coaxial cable KK to a tap of the coil La1.
  • 10 shows that the capacitor Ca1 can be formed by individual capacitors connected to one another and to the transmitter and receiver units T / R1, T / R2.
  • the transmitting and receiving units T / R1, T / R2 can also be coupled to the antennas A1, A2, A3 via a coupling coil.
  • the antenna system described so far (without capacitor Ct and switch St) and formed by antennas A1, A2 and A3 works well if the distance d12 between the first antenna A1 and the further antennas A2 and A3 never changes significantly (the distance d23 of Antennas A2 and A3, which are assigned to the same transmitting and receiving unit T / R2, is constant).
  • the measures described below further improve in particular the antenna system shown in FIG. 4.
  • the antenna A1 is tuned as narrowly as possible to the prevailing frequency of the transmission signals.
  • the data ds to be transmitted is preferably modulated using the FSK (frequency shift keying) method, which is described, for example, in Rudolf Switzerlandl, Digital Modulation Method, Weghig Verlag, Heidelberg 1991, on pages 183 ff.
  • FSK frequency shift keying
  • the frequency of the carrier oscillation is changed between two defined values which are assigned to the logic states "0" and "1".
  • a digital data signal ds is fed to a modulation stage FSK-M in the circuit arrangement shown in FIG. 1.
  • a control signal mod is fed from the modulation stage FSK-M to a frequency generator FG, by means of which the signals emitted by the frequency generator FG via a transmitter amplifier SV to the antenna system AS1a are keyed between two frequencies in accordance with the FSK method.
  • the antenna system AS1a has a parallel resonance circuit which consists of a capacitor Ca1, a coil La1 and a resistor Ra1, which corresponds to the losses occurring in the resonant circuit.
  • a capacitor Ct is additionally provided, which can be connected to the resonant circuit by a switch St, for example a transistor, which is generated by a signal tn emitted by the modulation stage FSK-M is controllable.
  • the switching over of the resonance frequency of the resonant circuit of the antenna system AS1a is practically synchronous with the switching over of the frequency of the keyed transmission signals.
  • the narrow-band parallel resonance circuit which consists of the capacitor Ca1, the coil La1 and the resistor Ra1, is therefore keyed by switching the capacitor Ct on and off in synchronism with the frequency shift keying of the transmission signals between two resonance frequencies.
  • the antenna system AS1a therefore has a virtual resonance circuit of high bandwidth and quality.
  • the transmission signals are therefore always emitted at maximum transmission power, regardless of the transmission frequency present.
  • a broadband input stage must therefore also be provided on the receiving side, which has a broadband resonance circuit of correspondingly low quality, or preferably, as shown in FIG. 4, two mutually coupled resonance circuits of high quality.
  • the antenna system AS1a provided in a first communication unit is inductively coupled via an air gap to an antenna system A21 provided in a second communication unit, which is connected to a load resistor R1.
  • a virtual equivalent inductance La12 is also shown, which can be determined by calculation based on the selected coupling.
  • the antenna system AS21 has a broadband parallel resonance circuit which consists of a capacitor Ca2, a coil La2 and a resistor Ra2.
  • the antenna system AS1b shown in FIG. 2 has, instead of the capacitor Ct, a coil Lt which can be connected to the parallel resonance circuit and by means of which the parallel resonance circuit can also be tuned to a second resonance frequency in a narrow band (see pass curves k ' A1 and k " A2 in FIG. 5).
  • FIG. 3 shows the antenna system AS1b from FIG. 2, inductively coupled via an air gap or the corresponding virtual equivalent inductance La12 to a broadband antenna system AS23, which consists of two narrow-band resonance circuits which have a capacitor Ca2; Ca3, a coil La2; La3 and a resistance Ra2; Ra3 and which are coupled to each other via a virtual replacement inductor La23 as described at the beginning.
  • 1, 2 and 3 which contain virtual inductors La12, La23, are therefore equivalent circuit diagrams of the physically present conditions.
  • a resonance circuit is used according to the invention, which can be tuned to the transmission frequencies in a narrowband and switchable manner and broadband to the frequencies of the signals to be received.
  • two capacitors Ct1, Ct2 are therefore provided which can be connected via switches St1, St2 to the already known parallel resonance circuit (Ca1, La1, Ra1).
  • the parallel resonance circuit can be tuned as follows, for example. When switches St1, St2 are open, the parallel circuit has the resonance frequency f2. When switch St1 is closed (switch St2 open), the parallel circuit has the resonance frequency fm. When switch St2 is closed (switch St1 open), the parallel circuit has the resonance frequency f1. The switch Stl (switch St2 open) is therefore closed for reception, as a result of which the capacitor Ct1 is connected to the parallel circuit. To increase the bandwidth of the parallel circuit (reception), a damping resistor Rt is also connected in parallel with the capacitor.
  • the modulation stage FSK-M controls the switches St1, St2 by means of signals tn1, tn2 in such a way that a broadband and virtually two narrowband resonance circuits are available for reception and transmission.
  • Switchable inductors can of course also be provided for the circuit arrangements shown in FIG. 11.
  • the connection of the resistor Rt or further damping resistors can also be carried out separately in order to set any bandwidth for the transmit and receive operation.
  • the resonance frequency of the tunable resonant circuit, e.g. 11 is preferably carried out by connecting or disconnecting impedances.
  • impedances e.g. voltage-controlled capacitance diodes that can be changed almost continuously or by leaps and bounds.
  • capacitors Ct and coils Lt are switched on and off.
  • the capacitors Ct are therefore preferably switched on or off when the voltage across the capacitor Ca1 crosses zero.
  • the coils Lt are preferably switched on or off at a maximum of the voltage across the coil Lal.
  • threshold value circuits TH1, TH2 are provided in FIGS. 1 and 2, which inform the modulation stage FSK-M by means of a signal trg at what point in time the voltage across the parallel circuit has fallen below or exceeded a certain value. It is only at this point in time that the capacitors Ct or coils Lt are switched on or off by the modulation stage FSK-M.
  • the use of the antenna system according to the invention can often hardly be used advantageously in broadcasting technology, e.g.
  • the required bandwidth, especially in the radio and television frequencies, is practically always available, because there is sufficient transmission power and because the antennas of the system can be installed in a stable manner, transmission systems in traffic engineering, which will be used in the future to transmit high data rates are provided and which operate at relatively low transmission powers and low frequencies from 1 MHz to about 50 MHz, can be significantly improved by the use of the antenna system according to the invention.
  • the use of the antenna system according to the invention results in particular advantages if individual communication units have to be powered.
  • the reduction in the coupling losses therefore results in a higher supply power available at the receiving end, or the transmission power can be reduced accordingly.
  • the measures according to the invention advantageously increase the distance between the levels of the useful and interference signals.
  • FIG. 8 shows two pairs of rails S1, S2 guided next to one another.
  • a railway train ZK provided with a mobile transmitting and receiving unit T / R2 is guided on the rails S1.
  • Ground-based transmitting and receiving units T / R1 are provided between the rails S1, S2 and are provided for data exchange with the vehicles ZK carried on the pairs of rails S1, S2.
  • information is often only transmitted from the ground-based to the mobile transmitting and receiving units T / R2.
  • bidirectional data transmission is also possible. Since the vehicles move at speeds of up to a few hundred km / h, there are only very short contact times of a few milliseconds between the ground-based and the mobile transmitter and receiver units T / R. Soiling, snow and ice are also to be expected. Furthermore, the national approval authorities only use systems with relatively low transmission powers approved.
  • the measures according to the invention extend the contact time within which the transmitting and receiving units T / R1 or T / R2 can share their information.
  • the path loss is thereby reduced, which means that transmitter and receiver units T / R1 and T / R2 can come into contact earlier.
  • FSK modulation frequency hopping method
  • a method with continuous modulation can also be used.

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EP96810372A 1995-06-09 1996-06-06 Procédé de transmission de données et système d'antenne en particulier pour systèmes de communication de circulation et circuit Withdrawn EP0747995A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH169795 1995-06-09
CH1697/95 1995-06-09

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EP0747995A2 true EP0747995A2 (fr) 1996-12-11
EP0747995A3 EP0747995A3 (fr) 1997-10-22

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0960797A2 (fr) * 1998-05-25 1999-12-01 Siemens Schweiz AG (Siemens Suisse SA) (Siemens Svizzera SA) Siemens Switzerland Ltd) Système de transmission en particulier pour systèmes de commande de trafic
CN106448224A (zh) * 2016-12-20 2017-02-22 朱广志 一种车船位置信号监控管理系统

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4799066A (en) * 1985-07-26 1989-01-17 The Marconi Company Limited Impedance matching arrangement
US5034697A (en) * 1989-06-09 1991-07-23 United States Of America As Represented By The Secretary Of The Navy Magnetic amplifier switch for automatic tuning of VLF transmitting antenna
EP0535363A2 (fr) * 1991-09-30 1993-04-07 Siemens Aktiengesellschaft Récepteur de signaux multi-porteuses modulés en amplitude, en fréquence ou en déplacement de fréquence
WO1994011754A1 (fr) * 1992-11-06 1994-05-26 Siemens-Albis Ag Procede et circuit pour la transmission de donnees entre deux stations
WO1996032755A1 (fr) * 1995-04-12 1996-10-17 Siemens Schweiz Ag Systeme d'antenne destine en particulier a des systemes de communication relatifs a la circulation

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4799066A (en) * 1985-07-26 1989-01-17 The Marconi Company Limited Impedance matching arrangement
US5034697A (en) * 1989-06-09 1991-07-23 United States Of America As Represented By The Secretary Of The Navy Magnetic amplifier switch for automatic tuning of VLF transmitting antenna
EP0535363A2 (fr) * 1991-09-30 1993-04-07 Siemens Aktiengesellschaft Récepteur de signaux multi-porteuses modulés en amplitude, en fréquence ou en déplacement de fréquence
WO1994011754A1 (fr) * 1992-11-06 1994-05-26 Siemens-Albis Ag Procede et circuit pour la transmission de donnees entre deux stations
WO1996032755A1 (fr) * 1995-04-12 1996-10-17 Siemens Schweiz Ag Systeme d'antenne destine en particulier a des systemes de communication relatifs a la circulation

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0960797A2 (fr) * 1998-05-25 1999-12-01 Siemens Schweiz AG (Siemens Suisse SA) (Siemens Svizzera SA) Siemens Switzerland Ltd) Système de transmission en particulier pour systèmes de commande de trafic
EP0960797A3 (fr) * 1998-05-25 2002-06-12 Siemens Schweiz AG (Siemens Suisse SA) (Siemens Svizzera SA) Siemens Switzerland Ltd) Système de transmission en particulier pour systèmes de commande de trafic
CN106448224A (zh) * 2016-12-20 2017-02-22 朱广志 一种车船位置信号监控管理系统

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