DE2212108A1 - Messaging system - Google Patents

Description

Patent attorneys 13. ^;

DIpI. Ing.C. Gelding,

Dipl. Ing. G. Koch ^{13 5! N} * ^{k / l} "* · ^ 1 ZI

Dr. T. Haibach
8 Nj chen 2

Kaufingerstr. 8, Tel. 240278

Sperry Rand Corporation "New York 1QO19 (USA)

Message transmission system

The invention relates to message transmission systems and relates in particular to the broadcast, the reception, demodulation and the use of very short electromagnetic baseband IRA pulses, for example of a duration in the sub-nanosecond range. The invention also includes a transmitter for electromagnetic radiation Energy impulses on

Known message transmissions operating with electromagnetic high-frequency signals require a certain frequency band vqu certain width in the overall frequency spectrum for their operation. With the growth of the types of radio frequency communication systems and their diverse and global application, it is becoming increasingly difficult to allocate frequency bands so that new transmitters do not result in frequency overlap in wavebands already assigned to other communication systems. Transmitters in the same and in remote wavebands corresponding to radio frequency interference in receivers increased the need and the cost of creating shields and other special design features, for example in

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Common types of radio receivers. Even the radiation the energy of the local oscillator must be carefully controlled

Any disturbance radiation above the extremely low power level considered permissible will affect the Usual radio reception disadvantageous. On the other hand, if the radiation level used is very low and even for Message transmission «is used, this radiation can only be used over extremely short areas and can even then be severe in the presence of other legal transmissions or by an electrical environment * - interfering signals are severely affected. It was To date, no radio frequency energy communications system has been proposed which is successful at substantial distances between the transmitter and receiver in a waveband can be operated that is already assigned to other receivers in the same geographical neighborhood. In particular, there is no known high frequency energy communication system of this type which is very low or low can work at legal power levels without being masked by interference. Furthermore, there is no known high-frequency energy message transmission device of this type which enables the transmission and reception of signals having an extremely wide frequency spectrum without the transmission of conventional message transmission signals being disturbed.

According to one aspect of the invention, comprised a communication system, a transmitter for transmitting a baseband signal, a receiver with an im essential non-scattering transmission line for reception

ORIGINAL INSPECTED

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of the baaisband signal, responsive to the baseband signal and means coupled to the transmission line for producing an output signal of substantially greater magnitude Duration than the baseband signal and on the output signal appealing utility facilities.

According to a further basic concept of the invention, a transmitter for the emission of electromagnetic Energy pulses created by a transmission line with balanced conductors, an essentially constant one characteristic impedance and with first and second ends, a power supply, near the first end arranged means for charging the transmission line according to a first time constant from the power supply, at the first end of the transmission line means connected in series for discharging the transmission line according to a second time constant, the Discharge means comprise first and second resistors, and comprises electrically actuatable switching devices and a pulse generator for controlling the switching devices, whereby the pulse generator through the power supply is activated.

A preferred embodiment of the invention takes the form of a radio frequency pulse communications system constructed and arranged to be information messaging without interfering with common types of radio frequency messaging and that on the other hand, in normal operation, essentially through the emissions from other communication systems or through electrical ambient interference signals is not affected.

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The preferred transmitter in accordance with the broader principle of the invention, suitable for use in the communication system, employs a non-fidelity transmission line (forming the transmission line means) for generating very short baseband or sub-nanoecond pulses of electromagnetic energy and to their radiation into the room, with a cyclic energy storage on the transmission line and alternating cyclic energy dissipation from this transmission line is used. The transmission line acts as a dispersion Free emitter, which emits the sub-nanosecond pulses essentially without interference * Such baseband pulses have an extremely wide energy spectrum; although the total energy share of any given transmitted Baseband pulse can be significant the few have Spectral lines that fall in the relatively narrow passbands of a conventional receiver have no effect in this.

The receiver suitable for the acquisition and demodulation of such short electromagnetic baseband pulses also employs a broadband, non-leakage transmission line antenna with circuitry compatible with a biased semiconductor detector element which is arranged in the antenna transmission line to instantly demodulate substantially the entire energy of the Baaisband pulses and to provide a corresponding output to be supplied, the one for use in common slot circuits suitable is. The receiver antenna system provides essentially the total energy of any undisturbed received Baseband pulse directly to the receiver detector the receiver can successfully handle impulse signals with a

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work very broad spectral expansion. This system also helps to operate with baseband pulse signals with spectral "" components, each of which has such a low energy content "that it cannot be recorded by common band receivers the level of noise or other interference, or signals near the receiver to be · Thus, received by suitable adjustment of the Auegangspegels the transmitter and the sensitivity or threshold of the receiver detector baseband communication signals in a simple manner by the receiver and demodulates _t be disturbed without other receivers and without these communications signals being disturbed to any substantial degree by other radio frequency energy transmissions.

The invention is explained in more detail below with reference to the exemplary embodiments shown in the drawing explained »

In the drawing show:

Pig · 1 is a schematic perspective view of the Impulse messaging system $

Figure 2 is a fragmentary perspective illustration of the receiver of the system according to FIG. 1j

Fig. J is a circuit diagram of the receiver according to Figures 1 and 2ι

4 a, k b, k c, 4 d and k e graphically representations

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of waveforms to explain the mode of operation of the message transmission «syatems, where in each case the voltage is plotted on the ordinate and the time on the abscissa;

Fig. 5 is a perspective, partially broken away View of a transmitter of the system of ^F ig. 1} FIG. 6 is a circuit diagram of the transmitter according to FIG. 51 Fig. 7 a, 7 b, 8 a, 8 b, 9 a, 9 b, 10 a and 10 b

graphic representations of waveforms to explain the mode of operation of the transmitter according to FIGS. 5 and 6;

11 is a schematic view of a modification

of the message transmission system according to Fig. 1 (

Figures 12, 13 and 14 are further graphical representations to explain the mode of operation of the message transmission system.

The communication system 1 according to FIG. 1, which operates with short baseband or sub-nanosecond pulses, uses a transmitter 2 with an antenna k which emits pulses or short baseband pulses and which interacts with a receiver 3 with an antenna 5 which receives a pulse or short baseband pulses. The transmitter 2 for short baseband pulses may be of the general type disclosed in the German patent. · (German patent application P 21 29 700.7) of the same Applicant there is described and the se beispielswei one of the antenna like antenna h

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and includes an electrically uniform transmission line system with constant impedance for the propagation of electromagnetic vibrations of the TEM mode. The transmission & line system is used in the transmitter for the interacting cyclical energy storage ant the transmission line and for the cyclical release of this energy by propagating along the transmission line for radiation at the opening end of an antenna section of the transmission line, which is designed as a horn-shaped or conical directional antenna line antenna k . Thus, the Übertragungsleitungssysteni is cooperatively used for signal generation by cyclic loading of the transmission line with a first charge value and also for the signal radiation into the room through discharge line at a time which is substantially shorter than the time ufladung for the ^A needed. The discharge of the transmission line causes a voltage oscillation to propagate towards the open end or the radiation opening of the antenna. This process causes the generation of a sharp impulse or a baseband impulse of a sub-nanosecond duration through differentiation, which is radiated into the room. The antenna of the German patent ... (German patent application P 21 29 700.7), like the antenna of the system described, has a large instantaneous bandwidth, so that it essentially produces very sharp pulse-shaped signals of sub-nanosecond duration with either a positive or a negative direction can radiate without interference or distortion. Furthermore, the antennas h and 5 can have broad transmission and reception characteristics, or they can be provided with focusing properties in a simple manner, so that the emitted or received energy is maximized in a predetermined direction.

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A specific construction of the transmitter 2 and the antenna k is explained in connection with FIGS.

The transmitter 2 and the associated antenna k of the message transmission system are constructed in such a way that they can emit a short Baaisband pulse or pulses which can reach the baseband pulse receiver antenna 5 directly or in some other way in order to be demodulated by the receiver 3 * The receiver 3 is a baseband or sub-nanoscurid pulse receiver for receiving and demodulating such very short electromagnetic baseband pulses and for delivering an output which is useful for operating slot equipment 3a, such as a display. The receiver 3 uses an essentially scatter-free, very broadband transmission line antenna 5 which covers a large or small spatial angular range and interacts directly with a specially arranged detector which is arranged in the transmission line for demodulating and detecting the total energy of the baseband pulses. As will be described with reference to FIGS. 2 and 3, a circuit connected to the detector element supplies a corresponding output signal which is suitable for use in conventional slot circuits and which also switches the receiver 3 up again to enable it to receive a to prepare the following short track band impulse. Since the official energy of the baseband pulse is momentarily supplied by the non-scattering antenna 5 to the detector element, the receiver 3 can work with pulse signals with spectral components, the amplitudes of which cannot be detected by conventional, relatively narrow-band receivers. One suitable for use as receiver 3 in the communication system

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Baseband receiver having properties is in that German.Patent .. · (German patent application. ·., our file number 13 65O, with the same filing date) the described by the same applicant.

As will be explained, the communication system which operates with short baseband pulses is shown here describes unique properties that make the use of this system to transfer information through space - from one location to another along an arbitrarily selectable path in a manner that essentially does not interfere with usual High frequency transmissions causes «As it will be seen further, the communication system 1, although it can be set to operate at very low peak and average power densities, essentially immune to the presence of random electromagnetic interference or to the presence of normal broadcast signals at normal levels.

As can be seen from Figures 1, 2 and 3, a suitable receiver antenna has a structure with a mirror image symmetry about a central plane at right angles to the direction of the vector of the electric field E, which sioh into the antenna, for example in the through the direction indicated by arrow 6 spreads. The same is the case for the cooperating transmission line 7 (FIG. 2) which comprises parallel wire transmission line conductors 8 and 9; conductors 8 and 9 are spaced-apart wire conductors made of a material that can conduct high frequency currents without significant ohmic losses

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the conductors 8 and 9 are constructed and arranged so that they the TEM mode propagation of high frequency energy support, the greater part of the electric field between the conductors 8 and 9 lies.

The TEM receiver antenna 5 still consists of two conically tapered, flat, electrically conductive planar parts 10 and 11. Parts 10 and 11 are, for example, generally triangular in shape, the Part 10 is limited by the conically tapering edges 12 and 13 and a frontal opening edge i4. In the same way, the part 11 is delimited by the conically tapering edges i6 and 17 and a frontal opening edge 18. The frontal opening edges 14 and 18 can be straight or curved. Each of the essentially triangular parts 10 and 11 is slightly frustoconical at the apex, the truncated cones 19 and 20 being constructed and arranged so that the conductor 8 smoothly without overlapping at the truncated cone 19 with the antenna part 10 and the conductor 9 is attached to the antenna part 11 smoothly without overlapping with a dome truncated cone 20. It's understandable, that the respective connections to the truncated cones 19 and 20 using available techniques to reduce as much as possible any impedance nonuniformity at the connections.

It will also be understood that the tapered portions 10 and 11 of the antenna 5 are made of a material having a high conductivity for high frequency currents and that they are in an apertured plate 15 (Fig. 1) of a material with low dielectric Losses that are part of the

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Receiver housing forms. The internal volume of the antenna can old be filled with an air-foamed dielectric material that has low dielectric losses in the presence of high-frequency fields, this material serving to keep the part IO in a fixed relationship to the Part 11 to hold. Alternatively, the conductive elements of the antenna 5 may be spaced apart by dielectric spacers and cooperate with them to form end walls for the assembly, thereby protecting the internal conductive surfaces of the antenna 5 from the effects of precipitation and corrosion.

As has been explained, the flat parts 10 and 11 of the receiver antenna 5 are connected with impedance matching to the two-wire transmission line 7, which can be seen in more detail in FIG. The transmission line 7 is constructed so that it has the same impedance as the transmission line comprising the antenna parts 10 and 11. The parallel wire conductors 8 and 9 of the transmission line 7 can be molded into a dielectric encapsulation element 21 in order to precisely define the distance between the conductors 8 and 9, so that the transmission line 7 has a constant impedance over its length. The dielectric element 21 can in turn be surrounded by a braided or other conductive shield 22, which is in a suitable location, such as. B. through a line 23, grounded 1st. The shield 22 may in turn be surrounded by a protective plastic cover element 2k of a well known type. The two-wire transmission line 7 is thus connected in a simple manner to the electronic circuit of the receiver 3, with signals from the line

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length of a diode 25 (Fig. 3). In general, the length of the transmission line 7 is between the Antenna 5 and the diode 25 short.

A cooperating antenna and transmission line system 5, 7 of the form shown in FIGS is a preferred antenna, in part because the desired TEM mode propagation is easily established in this system «The TEM propagation mode is preferred because it is the substantially non-scattering propagation mode and therefore its use is the Distortion or interference of the propagating sub-nanosecond pulse signal to be received is significantly reduced * The simple double transmission line arrangement also enables the construction of the antenna transmission line arrangement with minimal impedance irregularities. Furthermore, it is a property of symmetrical Type of transmission line forming antenna 5 such that its characteristic impedance is a function of b / h, where b is the width dimension of the major surfaces of parts 10 and 11 and where h is the distance between the inner surfaces of parts 10 and 11 is. For example, in the case of the antenna 5, the ratio b / h is kept constant because the ratio of b to h is kept constant will.

In the arrangement described, the antenna 5 is made compatible with the transmission line 7 by * that the value of the ratio b / h in the antenna is kept constant. In other words, if the relationship is hit b / h is kept constant along the propagation direction 6 in the antenna 5, the characteristic impedance of the

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Antenna 5 is constant along its length and can thus be made equal to the characteristic impedance of the transmission line 7 in a simple manner. Due to the result * »maintaining a continuously constant characteristic impedance and the TEM propagation along the Anteran® 5 and the line 7, frequency-dependent yeast lessons in di © <» sen are prevented, and the frequency spread is eliminated «The received sub-nanosecond impulse Therefore flows through the antenna 5 wad into the transmission line 7 * Sa the complete energy @ ά®τ amplitude of a sub-nanosecond "Baaisbandiapul3 © s" without any significant "reflection and without any substantial incurrence" of a shape or amplitude If the low level is supplied by the antenna transmission system to the diode 25, it is possible to recognize / that the receiver 3 can respond to extremely short base band pulses at a low level and an extremely wide spectral content, with any Part of this spectral content would not be detectable using conventional reception technology for wide pulses. Additionally, it is understood that suitable types of streuungsfr®iesi baseband antennas having different reception characteristics & n the illustrated antenna can replace ₀ For example, the azimuth All-An antenna, which in the US Paten i; Is. "Patent Application 832,337) describes _a used

Any sub-nanosecond pulse picked up by the antenna 5 is transmitted essentially without attenuation. tion in the two-wire transmission line 7 to the diode 25 conducted, which is preferably a tunnel diode or some other high-speed diode that can be used as a pulse or Baseband pulse detector can serve. A suitable diode 25 has a current-voltage characteristic with negative wi-

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deratand so that the diode 25 responds with a suitable bias to incoming impulses from the transmitting antenna k in such a way that its working point moves abruptly into the unstable range "whereby it becomes highly conductive. Although other semiconductor diodes can also be used" is a suitable one Diode the germanium tunnel diode 1 N 3717.

The diode 25 is connected to the conductor 8 via a small capacitor 26 and to the conductor 9 via a grounded resistor 27. The resistor 27 fulfills a task of adjusting the potential level, as a result of which the tunnel diode 25 can drive a transistor 33, and helps to achieve a correct impedance matching to the line 7, so that reflections are avoided. The capacitor Z6 also serves as a coupling capacitor and prevents damage to the receiver if the input is short-circuited by an unfortunate coincidence. A suitable source of bias voltage (not shown) for diode 25 is connected to terminal 28 to provide current flow to diode 25 through an adjustable resistor and a level adjusting resistor.

A second series circuit connected to the bias voltage terminal 28 comprises a resistor 31 "" a diode 32, which can be a conventional 1 N 9i4 ~ diode, and the transistor 33, which can be a conventional transistor of the 2 N 3 *> 38 type. A third series circuit connected to the bias voltage terminal 28 comprises a resistor 3k, an avalanche transistor 35 (avalanche transistor) which can be a selected conventional transformer of the 2N 706 type,

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and a resistor 36 »The resistor 36 is with a Tap 39 connected to a voltage source consisting of a potentiometer 37 and a battery 38. One fourth series connection connected to the bias terminal 28 comprises a resistor 4O and a capacitor 4i. A capacitor 42, which is also connected to the terminal connected, forms an alternating current earth connection.

A diode 43 is connected between earth and the connection point between the resistors 29 and 30. The latter connection point is connected via a diode 44 to the connection point between the resistor 31 and the diode 32. The diodes 4-3 and 44, like the diode 32, can be conventional 1 N 914 type diodes. The common connection point of the resistor 31 and the diode 32 is connected to the base of the transistor 35 via a resistor 45. The connection point 50 between the capacitor 26 and the tunnel diode 25 is connected to the base of the transistor 33 via a resistor 46. The connection point between the collector of the transistor 35 and the resistor 36 is connected to a terminal of the capacitor 41 via a line 47 "which also serves as an ungrounded output line for the circuit. A second ungrounded output line 48 is at the connection point between the resistor 40 and the capacitor 41 turned on.

Although other combinations of parameters can be used, typical values are different Circuit components follow

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Resistance capacitor

27 - 82 2212108 ohm R. 29 - 1 KOhra R. 30 - 390 ohm R. 31 - 2.2 KOhm R. 3 ^ - 22nd Ohm R. 36 - 270 ohm R. 40 - 56 ohm R. 45 - 330 ohm R. 46 - 390 ohm R. 26 - 100 pF C. 41 - 680 pF C. 42 - 1 pF C.

For the above values, the power source formed by the battery 38 and the potentiometer 37 can be set so that it supplies approximately + 150 V at the tap 39 o In addition, a -6 V bias voltage source can be connected to the bias connection 28 ₀

In operation, the tunnel diode 25 is biased very close to its breakdown point by manual adjustment of the resistor 29. For example, in the case of the Germanlum tunnel diode 1 N 3713 used as an example, a little less than 10 MA are required to bias the diode 25 close to its breakdown point. In this case, the voltage levels applied to transistor 33 are not sufficient to bring it into the conductive state, so that this transistor remains in the quiescent state. The diodes 32, 43 and kk also remain non-conductive. The avalanche transistor 35 therefore does not have a gate bias voltage. The collector potential of this transistor is due to the setting of the

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Tap 39 of the potentiometer 37 in such a way that this transistor transistor does not cause any disturbing saw-tooth oscillations can. The avalanche transistor 35 is therefore also in the quiescent state and the receiver is ready to receive of a short baseband input pulse.

Such a short baseband pulse, the shape and amplitude of which is retained in the antenna 5 and the transmission line 7, can, for example, have a duration of 0.5 nanoseconds and can cause an instantaneous voltage pulse along the tunnel diode 25 with a peak of, for example -0.1 V Such a signal is shown in FIG. 4a, the D & u @ r however being enlarged for reasons of clarity. The tunnel diode 25 switches momentarily from its state with low open-circuit voltage and positive resistance through the unstable state with negative resistance to its state with high voltage and positive resistance. This temporarily disrupts the current relationships in the remaining circuit. The transistor 33 is biased in the forward direction due to the presence of the resistor 46, and the circuit including the diode 32, the resistor 3f and the transistor 33 conducts a current (FIG. 4b) after a time delay peculiar to the transistor and the diode 32, as a result of which the positive signal according to FIG. 4c continues through the resistor 45 to the base of the avalanche transistor 35. The oscillation according to FIG. 4c begins for the special circuit described above also essentially 20 nanoseconds after the time t _Q , ie the point in time of the peak value of the short baseband pulse according to FIG. 4a.

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speaks, with a sharp rise and then falls

The positive oscillation according to FIG. 4c in the order of magnitude of + 10 Van of the base of the avalanche transistor 35 causes the series-connected diodes 43 and 44

draw a strong current through resistor 45. That Potential at the terminal 50 of the tunnel diode 25 changes abruptly, whereby the tunnel diode 25 is reset and their state is reversed. After a time shown in FIG. 4e, the tunnel diode returns to its state return. After a time shown in Figure 4e, it returns to its normal or idle state. The conductivity by the diode 32 is omitted, whereby the transistor 33 da » is protected from being protected by an excessive positive stress to be burdened.

The circuit is then further restored to its original idle state. The capacitor 41 becomes mainly by the resistor 34, the resistor 40 and the avalanche transistor 35 including Circuit path ii with an exponential discharge speed depending on the time constant of this discharge circuit. On the other hand, the capacitor 41 becomes significantly slower via the resistor 36 again charged.

As noted above, useful output signals, comprising pulses of relatively long duration, appear on output lines 47 and 48; these signals are of the general nature shown in Figure 4d and appear simultaneously. Ώ * χ · Pulse on line 47 essentially has a peak value of -100 V starting from

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the -6 V-PegeI ₅ and the length d of 6y% of the peak amplitude is substantially equal to 200 nanoseconds · The occurring on the line 48 pulse has, starting from the -6 volt level to a peak of substantially 30 V, and the duration of 63 $ of the peak amplitude is essentially 200 hanoseconds. The delay β dee sharp rise in the output pulses in FIG. 4b is again essentially 20 nanoseconds behind the peak at t of the short baseband pulse received according to FIG. 4a.

The output signals appearing on lines 47-48 can be connected to any desired grooving device (e.g., a signal processing device 51 and a cathode ray tube display 52) which upon receipt of pulses of conventional duration, such as are normally processed by conventional pulse processing circuits. Although the actual utilization device iat not a necessary part of the present invention is _f can be seen that it can take a variety of forms "For example, a single received by the antenna 5 sub-Nanos®- customer baseband pulse be regarded as an information transmission, and consequent occurring at the Auegangsleitungen 47 and 48 output can be displayed on the conventional CRT display _s which may be of the type in which the deflection of the indicator is triggered along a coordinate by the displayed pulse, the pulse even after a short delay is used to deflect the cathode ray along the second coordinate The signal processing device 51 and the display

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position 52 may alternatively, for example, count the number of sub-nanoecond pulses received by the processing device 51 in an arbitrary period of time or in a particular burst of pulses and then display the total count on a conventional numeric representation that takes the place of the cathode ray tube display 52 «A sequence of the Antenna 5 received sub-nanosecond pulses can have a modulation, for example a pulse interval modulation, which is demodulated in a simple manner in the usual way by the processing device 51 and either displayed on a display or; if the demodulated signal is an audio frequency signal, in the usual way for operating a Speaker or other audio frequency instrument can be used ₀

It can be seen that the receiver according to the figures 1, 2 and 3 is a broadband detector element, a receiver, which is responsive to any signal level above the bias level which may be determined by the characteristics of the particular tunnel diode 25. The amplitude of the at the receiving antenna 5 received pulse or baseband pulse can, for example, about 200 mV in one typical operating case, a value that is several orders of magnitude larger than the signals that are present in an urban environment due to common radiation sources, these interfering signals usually one Have microvolt levels «The receiver is accordingly 3, although it picks up essentially all of the signals over a very wide pass band, it is essentially immune to interference from conventional radiation sources including electrical S tor signals, such as. B.

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Malfunctions caused by the ignition system of internal combustion engines. The transmitter 2 shown in FIG. 1 and the antenna k can, for example, transmit a regular sequence or a substance-like pulse of pulses with extremely variable duration and low amplitude. In a typical case, these pulse-shaped signals have a duration of essentially 200 picoseconds and a pulse repetition frequency on the order of 10 KHz. The upper limit of the mean power radiated in the entire room can be less than 1 milliwatt. The spectrum of the transmitted signal is spread over an extremely large bandwidth, typically 100 MHz to 10 OHz. Accordingly, the power emitted in any typical narrow communication band is far below the thermal noise level of a typical receiver operating in this band "boron out" transmitted pulse hence the operation of the usual Ilosla »frequenz-Naohrichtenüberraipmgsauerüsturagen not although" it can be used in a remarkable way by the receiver »

To generate the short baseband pulses, the use in the present invention requires the use of tapes. "guren be lind 5 and 6, used · Aue ύφη Figures 1 and 5 'are, the transmitter 2 and the antenna can k ₉ as shown in Fi u seen that the. Anteim · h @ ± rt® arrangement is essentially the same as the antenna 5 used in the receiver 3. The Antonra® k umtaMt example, an arrangement '' sit a mirror image symmetry about a central Eb © n® under 's-eefaiesr Wiakeln, direction of the vector E dee electrical Feldes® the ± &<sh k propagates in the antenna. Da® equals © tE »ifTt for them

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herewith cooperating transmission line 60 (Fig. 5) zuι the parallel plate or -band transmission line conductors 6i and 6ia with the same shape. The conductors 61 and 6ia are spaced apart planar conductors made from a material that can conduct high frequency currents without substantial ohmic losses. Furthermore, conductors 61 and 6ia are constructed and arranged to aid in TEM mode expulsion of radio frequency energy, with the greater part of the electric field being between conductors 61 and 6ia, and with electric field E being substantially perpendicular to the conductors 61 and 6ia inner main surfaces of the ladder lies.

The TEM transmission antenna k also consists of two tapered flat electrically conductive planar parts 62 and 62a. The parts 62 and 62a are, for example, generally triangular in shape, the part 62 being delimited by tapered edges 63 and 63a and a front opening edge 6k. In the same way, the part 62a is bordered by tapering edges 65 and 65a and a front opening edge 64a. The edges 6k and 64a may be straight or arcuate * Each of the generally triangular portions 62 and 62a is slightly truncated at the apex, the truncated cone being constructed and arranged so that the conductor 61 is uniform without overlapping at the junction 66 with the antenna part 62 is connected, and that the conductor is connected and uniformly 61a without overlapping on Verbindungepunkt 66a to the antenna portion 62a * Ss is understood that the respective connections 66 and 66a using known techniques to substantially reduce any Zmpedanc UN-

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uniformity are formed.

It is further understood that the tapered portions 62 and 62a of the antenna k are made of a material that is highly conductive to high frequency currents. It can also be seen that the inner volume of the antenna h can be filled with buckets of dielectric material, which has low losses in high-frequency fields acts in fixed relation with respect to the conductor 6ia and likewise for the part 62 with respect to the tapered part 62a. Alternatively, the conductive elements of the transmission line 60 and the antenna k may be dielectric -. Spacers are fixed at a distance from one another, these spacers together forming end walls for the arrangement, whereby the inner conductive surfaces of the antenna transmitter arrangement are protected against the effects of precipitation and corrosion o For example, thin vertical walls (one of which at 68 in Fig. 5) of low loss dielectric sheet material can be used in conjunction with the transmission line conductors 61 and 6ia. Sidewalls for separating the planar portions 62 and 62a may be in the form of tapered low-loss dielectric sidewalls 69a and 69a; such side walls, together with a thin front or weather barrier 59 of dielectric material, provide mechanical strength for the antenna k with low losses and help protect the interior of the antenna. It is understandable that the plane, the antenna opening

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- 2k -

defining parts 6Z and 62a can be tapered exponentially rather than linearly

The transmission line 60 and the transmitter antenna k of FIG. 5 are preferred in part because the TEM mode propagation can be easily established therein. The TEM propagation mode is again preferred because it is the substantially scatter-free propagation mode and its use therefore substantially reduces the disturbance of the baseband pulse signal which is propagating and which is to be emitted. The simple symmetrical transmission line construction enables the antenna h to be constructed with minimal impedance irregularities. Furthermore, it is a property of the symmetrical nature of the transmission line of the antenna h and the design of the transmitter 2 that the characteristic impedance is a function of b / h, where b is the width dimension of the main surfaces of the parts 62 and 62a and h is the distance between the inner end faces of parts 62 and 62a. As in the case of the antenna 5, the ratio b / h in the transmission line OO is kept constant because b and h are constant.

According to the invention, the transmitting antenna k is made compatible with the transmission line 6o in that the same value of the ratio b / h is used for both elements. The characteristic impedance of the transmitting antenna is thus constant over its length and can easily be made equal to that of the transmission line 60. By maintaining a continuously constant characteristic impedance along which the transmission line 6 and the antenna h include

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Arrangement In this arrangement, frequency-dependent reflections avoided · To simplify the explanation was for the representation of FIG. 5 generally triangularly tapering level arrangements for the parts 6Z and selected 62 · However Ee should be apparent that other arrangements easily executed who " those that maintain a constant characteristic impedance according to the above rules and that these arrangements could also be used.

The system for energizing the transmitting antenna k NaOH FIG · points compatible with this antenna properties and 1st example symmetrically, and avoids the complicated disadvantages of a transition-balancing transformer or other transition elements "The system of Fig. 6 solves these problems and uses suitably WEIS® the symmetrical double assembly of the transmitting antenna hour as part of Ladeleittffig for the baseband Iispißla®rs? e · "supply generator from"It's Veratasaeillieh because © simplifications in the Zeietassng naoh Figo 6 were to the arrangement and operation of d®v much! flat To be able to explain the device better "For example, it can be seen that Fig. 6 the parts 6Z and 62a of Fig." Have parts 62 and 62a. As a further example, the connections 66 and 66a in FIG. 5 are represented by connections 86 and 86a in FIG. 6. The symbols 6% and 6ta, FIG. 5 are represented in FIG. 6 by the symbol 81 mtd 81a and

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denote the opposite conductors of the transmission line 6O. Certain dimensions in Fig. 6 are enlarged, for example the distance h between the conductors 81 and 81a of the line 60, for convenience.

At the left end of the line 60, the conductors 81 and 81a are connected by a series circuit which comprises a battery 90 connected between two charging resistors 91 and 91a each having a resistance value of R / 2 ohms. At the end of line 6O adjacent junction points 86 and 86a, conductors 81 and 81a are connected by a series circuit comprising an electrically operated switch 92, which may be in the form of an avalanche transistor or other transistor switch, and which extends across battery 90 the resistors 91 «91a, 96 and 96a is switched on. Furthermore, an astable multivibrator 9h is connected along the battery 90 and is connected via a capacitor 93 to the base of the transistor for controlling the conductivity state of the transistor 92. Resistors 96 and 96a each have a resistance of r / 2 ohms, where r is equal to the characteristic impedance of line 60 (and the transmission line comprising conductors 82 and 82a). The transistor 92 is also provided with a base-to-ground resistor 93a.

The astable multivibrator or pulse generator can produce a regular bipolar oscillation, such as as B. the vibration train 95 of FIG. 6, with a predetermined

Generate pulse repetition frequency for actuating the transistor switch 92 · During operation it can be seen that the transistor switch 92 is initially generated by the pulse generator

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is kept non-conductive for a time sufficient for the entire arrangement, including the conductors of the line 60 and the conductors 82 and 82a, to be charged to a potential difference V which is equal to the potential difference supplied by the battery 90 bsi dom the charger of an effective capacitor C. ₁ is. On the next cycle of oscillation 95, transistor switch 92 is rendered conductive, forming a conductive circuit path across resistors 96 and 96a. The effect is to insert a jaweita or effective source B in series with first source A or battery 90 which, however, has a reverse polarity baaogesi to the polarity of the first source A.

The Figurren 7a "8a, 9a and 10a show the positive voltage Y _P supplied by the source A or the battery 90, as a positive constant voltage to successive time intervals in the Bet £ * iebsisykXus _o The same set of figures shows the progression the negative oscillation due to the second or effective source B at the same successive intervals. For example, Fig. 7a shows the situation at the point in time at which the transistor 92 is made conductive; It should be noted that the oscillation or wave has not yet started to flow around the effective second source B.

In Fig. 8a the negative well has the voltage -V / 2 from the effective second source B bogonnen * in the direction flow towards the opening of the transmitting antenna 4. When the opening ends 64, 64a of the conductors 82 and 82a are reached Fig. 6 and after the reflection the situation is in Fig. 9a

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shown »Ee can be seen that the -V / 2 oscillation when reaching the respective opening ends 64, 6hm. the antenna conductor 82 '82a is reflected and begins to flow back towards the connection points 86, 86a. The total contribution of the second or effective source B starting at the time of reversal is now -V volts. It can be seen that the total potential due to the actual and effective sources A and B between the conductors 82 and 82a at the opening ends Sh ₉ 6ha. the antenna suddenly drops from + V to zero at the time of reversal) this time is of primary interest in the operation of the transmitting antenna h. The wave produced by the effective source B continues its backward movement towards the connection points 86, 86a until the antenna conductors 82, 8i! A, which served as part of the charging line for the system, are in? are essentially completely discharged when the value of r is the characteristic impedance of the _{line comprising the conductors 82 1} , 82a. The charging cycle is then started again when the pulse generator 9h makes the switch formed by the transistor 92 conductive again. The system can be operated cyclically repeatedly.

It is easy to understand that the front opening edges 6h, 6he. total potential difference se resulting from the antenna for the same successive points in time as described above can be represented, as is the case in the respective FIGS. 7b, 8b, 9b and 10b. It can be seen that the potential along the antenna ffming due to the actual source 90 (or A) progressively through the migration of the wave due to the second or effective

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Source · B is canceled, the movement of this wave in the direction of the opening 64j 64a is triggered while the transistor 92 is conductive and this wave is reflected at the opening, whereupon the radiation takes place _β and ultimately a discharge through the Conductors 82 and 82a formed line is effected and the returned wave is absorbed in the resistors 96, 96a.

As mentioned above, the time of reflection of the wave from the effective source B is at the distance L. along the conductors 82 and 82a (the opening of the transmitting antenna 4) of primary interest · Due to the finite characteristic impedance r of the transmitting antenna system reverses the leading edge of the -V / 2 shaft going into the between at the ends 64, 64a of the antenna, which as a result is an open circle, the opening or orifice defined in motion, reverses its direction of flow while maintaining its previous polarity. The emission of a pulse

dV or baseband signal proportional to -rr in the room

u C

occur at this point · No further emission can occur until transistor 92 has been put into another cycle by pulse generator 94 and conductors 82 and 82a have been recharged from the battery. If, as was noted above, the resistance r of the sum of resistors 96 and 96a is equal to the charakteristischext impedance of the transmission line of the parts 62, 62a, the reflected wavefront finally 96e _f, and the potential ends in the resistors 96, "dlfferenz length of the entire line drops to essentially zero. The line then begins to recharge to approximately rv / R volts, with charging taking 2 r C ₁ seconds.

209839/1171

As can be seen, the baseband pulse receiver 3 can be used in the communications system to receive information communications in a variety of ways, _for example by receiving a single sub-nanoseland baseband pulse from dsm transmitter 2, whereupon an output pulse with a Duration of, for example, on the order of 100 nanoseconds is generated and this output pulse is shown on the display 52 according to FIG. 3. In this case the transmitter 2 according to FIG. 5 can for example be operated by manually closing a switch corresponding to the transistor 92 and at the same time disconnecting the battery at one of its connections in such a way that the transmission line 60 cannot be charged. Equivalent electronic operation is simpler Way to recognize »

More sophisticated arrangements for the transmission of information messages from the transmitter 2 to the receiver 3 are possible. For example, the multivibrator 9k according to FIG. 6 or other known types of pulse generators for forming a square pulse train similar to the oscillation 95 can be designed in a simple manner so that they cause the transmitter 2 and each antenna k to emit a message transmission which _{comprises 2. B 0} a train of 100 base line pulses. As noted above, when detected by the receiver 3, such a sequence can be passed on to a conventional counting device in order to count the 100 pulses with a duration of 100 nanometers, the total count being shown on a numerical display. Well-known pulse generators, which in addition to the multivibrator 9 ^ for

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can be used for the purpose, can be changed in their pulse repetition frequencies in the usual way from one frequency to the other, manually or by electrical control signals, usual, in the processing device 51 existing pulse frequency demodulation circuits can then for processing the pulse frequency modulated 100 nanoseconds - Pulses are used to achieve a representation of the frequency - as a message on the indicator. In the same way, pulse interval modulation in the transmitter 2 and a demodulation which interacts with it in the receiver 3 can be used for the transmission of information messages 2 and is available for deriving the information at the receiver 3 with the aid of well-known demodulation techniques which are operated with the aid of the relatively long pulses generated in the receiver 3. The versatility of the application of the message transmission system is further explained with reference to FIG. 11, wherein This figure shows a real message transmission system for sending messages from a transmitting station W to a receiving station X and with, for example, an obstacle in the form of a mountain 99 between the stations V and X. The transmitting station W uses a transmitter 2 and a Se nd antenna k of the form shown in FIG. Similarly, the receiver station X a receiver antenna and a receiver 5 3 ^"1 uses the form shown in Fig. 1.

At station Y, which is on the top of mountain 99 is arranged, an intermediate system is provided which consists of

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a receiver 3a with an antenna 5a, the Si » signals to be retransmitted to a transmitter 2a with an associated antenna 4a. It is understandable that the Baseband pulse receiver 3a equal to the baseband pulse « receiver 3 according to FIGS. 1 and 3, and that the base band transmitter 2a is the same as that according to FIGS. 5 and 6. It can be seen that the waveforms according to the figures 4b and 4c on lines 47 and 48 according to Fig.3 directly: can be used to control a known square pulse generator or a pulse shaper circuit, to produce an output signal equal to that of the I «- ' pul «generatorβ 94 according to Flg. 6 1st so that the Sohwingungs Form 95 is generated for the operation of the transmitter 2a - 'and for the subsequent reception of the baseband pulses is required by the receiver 3 at the station X · At the station X, the output of the receiver 3 in the Signal processing circuit 51 and the representation 52

can be used as explained in connection with FIG. ;

The message transmission system of the various Figs

Ren is characterized by a baseband pulse generator

«« Is worthwhile, which can generate impulses of sub-nanosecond duration for a carrierless communication that ^;

a general view in the tent area a three « have an oval shape »The Baals * can produce typical catfish line duration of such triangular baseband pulses • Expand a value of a few hundred picoseconds «Such impulses have an ex« · a tremendously wide energy spectrum, which runs essentially from direct current to an infinite frequency, jwtooh with oscillating and aloh decreasing amplitude- ♦ Whilst the entire energy content of the other base

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band impulses can be considerable can ribbon pulse received substantially all of the spectral lines of each incident base "* * with the exception that a time is required in order to generate a pulse with an energy content and having a duration at the output of the baseband receiver * of the operation of conventional Impulsnutzschaltungen 51 s 52 suitable there is no dependency of the receiver operation on the previous or future reception of a transmission, ie each received baseband pulse is treated as a completely separate incident "with no frequency-dispersive circuits and no resonance circuits that require carrier transmission and which generally require many cycles of a carrier input signal before sufficient energy is built up in the receiver to produce an output "

The theory of operation of the communication system can be readily understood from the foregoing discussion. The following simple analysis of the invention can be however, it can be used as one of several possible analyzes * which can alternatively be selected * um explain the mode of operation of the communication system, which works with short baseband pulses, is understandable * that it is not limited to the use of the following analysis, as others Analyzes can be used equally well »The purpose of the The selected analysis is to determine the time domain and frequency domain conditions in the treatment of the

209839/1171

Contrast carrierless short baseband signals used in the present invention and others " seldom such parameters on the noise level in a conventional narrowband pulse receiver and on its characteristic To refer to interference level.

Certain assumptions must be made to simplify the analysis. First it will be a rectangular one instead of one precisely triangular baseband pulse that has the following form:

p (t) = 1 t ^ \ (1)

p (t) = 0 t> I

This pulse is shown in FIG. As it is above noted, the duration of the pulse measured at the baseline of FIG. 12 may have a normalized amplitude of 1 volt are a few hundred picoseconds. The pulse described in FIG. 12 has a frequency range Araplitude spectrum (volts / radians) as shown in Fig. IJ is the first zero crossing in the amplitude spectrum at:

f = A (2)

When each amplitude of the curve of Fig. 13 is squared, the energy spectrum of the pulse signal is obtained. By integrating the squared function from the frequency SuIl (direct current) up to f ^, = * 1 / * it can be seen that 90 % of the energy is concentrated in the area defined in this way.

Introducing a first approximation using Parsevall's theorem, the function is the spectral Energy density approximated by Flg. 14 given. The function

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the power spectrum density can be obtained in a simple manner by dividing each ordinate in Fig * l4 by Λ *

It is assumed that the usual narrowband receiver "whose interference is to be avoided, has a pass band with a center frequency of f _Q and a bandwidth of Δ f". The magnitude of the peak signal power in the band is Δ f due to the incident square pulse according to FIG then given by:

Peak = < ^{1) 2} * ** ^{Δ f (5)}

or, if the imp-ils according to Fig. 14 has an amplitude of V volts having;

^p peak _ze - r * a - δ fw

The average power depends on the duty cycle or the pulse duration and the pulse repetition frequency « The average performance is given by:

Ψ = V ² /> Δ f) / f (5)

where T is the time between pulses «. Hence: P = (V ² > ² * Δ f) / f (6)

The performance in the band of an ideal narrowband receiver due to the thermal noise is given by:

P _n · K - T. Δ f (7)

where K is the Bolsmann constant and T is the temperature in degrees Kelvin »For a non-ideal receiver:

209839/1171 ^{e /}

P _n «NF- K · Τ · Δ f (8)

where NF is the noise figure of the receiver.

The condition in which the possibly interfering pulse signal is equal to the noise signal is of interest} this condition is seen as a minimally detectable signal interference situation denotes »This situation is obtained in a simple way by equating equations (5) and (8):

(V ² · ϊ ² ° Δΐ) / ¥ * NF * Κ «Τ · Δ f (9)

V m 4 / NF K * Τ Τ (10)

Equation (10) clearly shows that as the pulse width becomes smaller, the pulse signal voltage V correspondingly must become larger in order to maintain the same level of interference. For example, assume that:

λ = 200 χ 10 seconds

T β 10 seconds

T - 293 ° Kelvin

K «1.38 χ KT ¹⁶

NF = 10,

Substituting these values into equation (10) gives one Value of V equal to 30 volts · Thus must be below the assumed circumstances a 30 volt sub-nanosecond pulse the input connections of a standard narrowband receiver must be created so that this is sufficient * to minimize

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to generate a recognizable interference signal on the receiver detector »

It will be recognized that the invention is a pulse or Baseband high-frequency communication system, which is particularly suitable for the use of emitted pulses, with a low total energy level that have a spectral content that covers a very broad band is scattered "so that there is no significant contribution to the electrical background noise level, so that the System is far below the levels * which would interfere with state-controlled radio frequency transmissions * The Transmitter of the system may have a cooperating baseband receiver of such a novel type excite the receiver mainly through environmental disturbances or conventional impulse transmission systems is not affected. Since the transmitter can work with very low energy consumption »the costs for the Power supply as well as reduced in size. Furthermore, in such a low-power operation inexpensive components have a long service life in the entire receiver. This also applies to the Receiver to and both the receiver and the transmitter are of a very simple type and very inexpensive installation, maintenance and operation * and are easy to use with common information input and home equipments customizable ».

Claim

209839/1 171

Claims (1)

Claims Message transmission system, characterized by a transmitter (2, 4) for sending out a Baseband signal, receiver (3 * 5) with essentially Dispersion-free transmission line media (8, 9) for Receiving the baseband signal, responsive to the baseband signal and circuit means (25) responsive to the transmission line means (8, 9) for generating an output signal of much greater duration than that Baseband signal, and useful facilities (51> 52), which respond to the output signal. 2. Message transmission system according to claim 1, characterized in that the baseband signal at the receivers (3, 5) has an amplitude which is sufficient to momentarily activate the circuit devices cause the generation of an output signal to be initiated 3 «message transmission system according to claim 1 or 2, characterized in> that the transmitter (2, 4) has devices for interference-free transmission includes an electromagnetic pulse with a sub-nanosecond duration and broadband spectral line content, the energy in any selected spectral line being substantially below the ambient noise level lies. 4. Message transmission system according to claim 3 *, characterized in that the transmitter (2, 4) furthermore dispersion-free transmission line means (60, 209839/1171 62, 62a) having first and second ends, electrical source means (90) at the first end for charging the further transmission line means (60, 62, 62a), switch means (62) for discharging the further transmission line means (60, 62, 62a) and opening point (64, 64a) at the second end to emit the electromagnetic pulses with a sub-nanosecond duration. 5. Message transmission system according to claim 3, or%, characterized in that the the former, essentially dispersion-free transmission line means (8, 9) Broadband transmission line means for collecting and propagating the electromagnetic Pulse signals in the TEM transmission line mode include 6. Message transmission system according to claim 3 * k or 5j, characterized in that the response devices to the electromagnetic sub-nanosecond pulse include a semiconductor diode (25) with first and second states which are in energy exchange relationship with the first-mentioned, substantially dispersion-free transmission line means (8, 9 ) connected is. 7. Message transmission system according to claim 6, characterized in that the on the circuit devices responding to electromagnetic sub-nanosecond pulses first circuit devices (27, 28, 29, 30) to bias the semiconductor diode in the first State include such that the semiconductor diode (25) momentarily when the electromagnetic sub-nanosecond pulse hits in substantially undisturbed form changes its state from the first to the second state that the 209839/1171 Circuit devices continue to be second, with the first Circuit devices (31, 32, 33) connected to circuit devices (27, 28, 29, 30) for generating an output oscillation with a duration greater than the duration of the sub-nanosecond electromagnetic pulses and third Sehaltungseinrlehtungen (34, 35 * 36) include the one version use the output oscillation to return the semiconductor diode (25) to the first state. 8 · Message transmission system according to claim 1, characterized in that the transmitter (2, 4) emit a sequence of sub-nanosecond electromagnetic baseband pulses that form the baseband signal form, and that the circuit devices are fed to the sequence of the transmission line means (8, 9) respond to electromagnetic pulses of sub-nanosecond duration, the output signal being an output sequence of non-overlapping oscillations each of greater duration than each of the electromagnetic pulses with sub-nanosecond duration is, and wherein the utility devices (51 * 52) respond to the output sequence. 9. Message transmission system according to claim 8, characterized in that the transmitter (2, 4) TEM mode substantially dispersion-free transmission line means (8l, 8la, 82, 82a) with first and second ends, electrical source means (90) on the first End of charging the transmission line means (8l, 8la, 82, 82a), switch means (92) for repeatedly discharging the charged transmission line means (8l, 8la, 82, 82a) and an opening (64, 64a) at the second end for emitting the train of electromagnetic wave pulses with a sub-nanosecond duration include. 209839/1171 10 message transmission system according to claim 9 * marked by holder control devices (94) for modulating an information carrier Characteristic of the sequence of electromagnetic pulses with a duration of sub-nanoseconds. 11 * Message transmission system according to claim 10 » characterized by switch control means (94) for modulating the number of electromagnetic Sub-nanosecond pulses in the sequence. 12. Message transmission system according to claim 10, characterized by switch control devices (94) for modulating the pulse repetition frequency of the ¹ electromagnetic pulses with sub-nanoset duration in the sequence. 15 message transmission system according to claim 10, characterized by switch control means (94) for modulating the operating frequency of the switch means. l4. Message transmission system according to claim 10, marked without t by switch control devices (94) for pulse interval modulation of the electromagnetic pulses in the sequence. 15 message transmission system according to claim 10, characterized in that the time between successive states of the switch means is greater than the duration of each of the individual non-overlapping output oscillations. 209839/1171 l6 «message transmission system according to claim 10« characterized in that the receiver utilization devices (51, 52) have means fei) for demodulating the include the information-carrying characteristics of the sub-nanosecond series of electromagnetic pulses. 17 «Message transmission system according to claim 16, characterized by on the devices (51) for demodulating the information-carrying characteristic of the sequence of electromagnetic pulses display devices with sub-nanosecond duration (52). 18. Message transmission system according to claim 11, characterized in that the receiver user devices (51, 52) Means for counting the number of electromagnetic sub-nanosecond pulses in the Include episode. 19 message transmission system according to claim 12, characterized in that the receiver utilization devices (51> 52) Devices for demodulating the frequency-modulated pulse repetition characteristics of the Include electromagnetic pulses with sub-nanosecond duration in the sequence. 20. Message transmission system according to claim 15, characterized in that the receiver user devices (51 * 52) devices for measuring the Include operating frequency of the switch means (92). 21. Message transmission system according to claim 14, characterized in that the recipient 209839/1171 ^{# / <} useful devices (51, 52) Ira pulse interval demodulation devices lock in. 22 * message transmission system according to one of the preceding claims, characterized in that that the transmitter symmetrical transmission line position (8l, 8la., 82, 82a) with a substantially constant o characteristic impedance and first and second ends., I: power supplies (90), adjacent to the first end Means for charging the transmission line means (8l, 8la, 82, 82a) corresponding to a first time constant from the power supplies (9G), in series to the transmission line means (8l, 8l, 82, 82a) connected to the first end means (96, 96a, 92) for discharging the transmission line means corresponding to a second time constant, the discharge means having first and second resistors (96, 96a) and electrically actuatable holder means (92) and a pulse generator (94) for controlling the holder means (92), the pulse generator (94) operated by the power supplies (90) will" 23. Message transmission system according to claim 22, characterized in that the electrically actuable holder means (92) is a transistor switch include. 24. Message transmission system according to claim 23, characterized in that the pulse generator (94) has a multivibrator holding timfasst which is switched on capacitively in order to control the conductivity state of the transistor holder (92). 25. Message transmission system according to claim 22, characterized in that the symmetrical 209839/1171 / Transmission line means include first and second conductive plates (62 , 62a) of frusto-conical truncated triangular shape defining an interior area. 26. Message transmission system according to claim 25, characterized in that the interior the symmetrical transmission medium with dielectric Material is provided to hold the first and second conductive plates (62, 62a) in mutually fixed relationship to hold 209839/1171 Blank page