DE1516901B2 - Electronic goniometer - Google Patents

Description

Electronic goniometer for a radio beacon with a carrier source, generators for generation sinusoidal low-frequency and medium-frequency modulation signals, a frequency modulator for

i bib

3 4

Combination of the two modulation signals to form the carrier on the antenna arrangement, with generation of a combined modulation signal, one of the carriers directly from the modulated carrier for Amplitude modulator for modulating the carrier the omnidirectional antenna is obtained, four radio waves the combined modulation signal, an onion generator for the direct generation of performance for generating an antenna arrangement 5 distorted control signals of the modulation frequency, from omnidirectional antenna and crossed directional a double bridge amplitude modulator with von antenna system with the help of the resulting control signals acted upon varactor diodes Modulation signal modulated carrier and two or as a function of these control signals impeaus an amplitude modulation of the carrier with dances in the bridge branches to generate two Using the low-frequency modulation signal hereto sinusoidal sideband parts with suppressed previous sideband signals with suppressed carrier predetermined relative phase shift, Carriers, the modulation envelopes of which are shaped by a pre- whereby the distorted control signals are certain phases are shifted from one another. that taking into account the nonlinear cha-

In radio navigation systems, especially VHF characteristics of the varactor diodes, sinusoidal side

Omnidirectional beacon systems, 15 band oscillations were created.

rend a number of years mechanical gonio that has the advantage of no wearing parts

meter must be used to generate double sideband signals and that the goniometer

used with suppressed vehicle. At one in which is tunable and adjustable without the operation

Practice widespread system of this type will have to be interrupted. It can e.g. B. self-

the double sideband signals with suppressed carrier 20 made electronic error corrections

The transmitting antenna is fed in such a way that its Modu- are, so that the lobe shape of the rotating

lation envelopes are phase shifted by 90 °. Beam, if necessary, for azimuth errors

The antenna arrangement is such that it can be compensated.

the two phase-shifted signals in connection- According to a low harmonic formation

training with a non-modulated HF omnidirectional beam 25 particularly favorable further development of the invention

signal used to generate a directional beam, the function generators hold waveformers that

that a circulating radiation diagram gives the control signals the non-linear character

and appears as a rotating beam, the characteristic of the varactor diode compensating amplitude

although the antenna system used is stationary. give course of study.

The omnidirectional signal serves as a reference carrier and 30 In another embodiment of the invention

contains a frequency modulated signal that is used to block direct current voltage in the

Phase with the rotating beam by means of an on-board branch of the varactor diode bridge capacitors

navigation receiver can be compared to provided.

the azimuth of the aircraft with reference to the transmission After a further training of the invention

station (see e.g. German patent 35-compliant goniometer, which has a particularly

576 862 with rotating transformer). times the bridge adjustment is achieved, move the

Although the mechanical goniometer has its function generators and phase shifters the Pha services has met, each of the mecha- nisms of the control signals adhere to one another in such a way that the Niche device has its own disadvantages, in which impedances dependent on them are provided in the bridge moving parts, the frictional forces 40 branch the bridge between the two bridge circuits and subject to wear and tear. Alternately synchronize radio navigation systems.

must be kept in operation without interruption

and consequently cannot periodically change another embodiment of the invention

be switched to repair the goniometer by that the control signals are periodic signals

and wait. The rotors of the adjustable con 45 with the same period and that with the

Capacitors of mechanical goniometers are in bearings varactor diodes of the one bridge circuit first

held, which eventually expire, so that the con-function generators are coupled, the first

capacitors exchanged and replaced by new ones emit control signals that are such mutual

Need to become. Phases have that the a bridge circuit

Another difficulty with a mechanical goniometer that is briefly calibrated at 5 ° in half the period is that it is because of the and that with the varactor diodes of the other movement of the components not matched during operation of the bridge circuit, second function generators can be trimmed or trimmed. To adjust the coupling, the second control signals emit that mechanical goniometer whose motor, the other bridge circuit, must also be switched off and the operation of the system is briefly adjusted for a short period of half a period.
to be interrupted. This leads to an adjustment.Other structurally favorable refinements are based on the approximation method, as it goes without saying that the phase shift between those of the system caused by the phasing effect of an adjustment on the operation can only be observed when the first and second control signals the same as the phase goniometer is working again and the carrier and shift between the modulation envelopes, the modulation signals are applied. is; that the first and second function generators

The object of the invention is therefore to give a Gonio two control signals, each in order to to create meters without moving parts, so that the 180 ° are out of phase with each other; that the mechanical goniometers have their own difficulties, two bridge circuits each avoid four bridges will. 65 branches, each paired with one of the

According to the invention, the object is achieved by applying control signals.

a modulation suppressor for generating a. In another advantageous development of the

modulation-free carrier in phase with the modu- Invention contains the modulation suppressor for

5 6

Generation of an input signal of constant amplitude of 9960 Hz and by means of the 30 Hz signal of the tude an automatic gain control. Source 18 is frequency modulated. This together

To compensate for lobe errors, a signal can be sent to the circular beam input according to another embodiment of the invention VHF omnidirectional antenna supplied and forms the dung the function generators an adjustable 5 a component of the radiated navigation resistance contain. signals.

The composite that occurs at output 20 results in particularly favorable tuning conditions

According to another development, the signal is also coupled to a modulation under the varactor diode bridge on the middle plus pusher 22, which emits at output 24 the modulation-free 110 MHz carrier that can be tuned to twice the smallest capacity. The Mo inductor contains. Dulation suppressor 22 is constructed in a conventional manner. A favorable coordination can also be achieved and, for example, a high level can be achieved in that the varactor diode bridge in a saturated tube amplifier stage with AVR feedback has another development to the lowest capacitance of the development. Under the influence of the automatic diodes, which can be tuned in parallel to the bridge gain control, 15 see gain control in connection with the outputs contains inductances. the tube operating in the saturated state is a favorable adjustment, according to the amplification of the stage, results in an inverse function of another embodiment of the invention, just as the amplitude of the envelope curve, so that at the output, if the varactor diode bridge appears in each input 24, a constant output signal appears, output circuit a pair of on the average capacitance ₂₀ The output 24 of the modulation suppressor is the diode contains tunable inductances. with the input of a varactor diode bridge-The invention is connected in the following description circuit 26, which, as explained in more detail below of exemplary embodiments in connection with the, two bridges each with four branches on drawings explained in more detail. It shows points that fed via a common input F i g. 1 is a block diagram of a 25 according to the invention. The bridge circuit 26 has two extensions radio navigation system, corridors 28 and 30, which are connected to the input of the VHF Fig. 2 is a schematic electrical circuit diagram of omnidirectional antenna for the variable phase coupled to the bridge circuit according to the invention.

F i g. 3 is a graphical representation of the characteristic curve. The task of circuit 26 is to provide two

a reverse biased varactor diode, 30 double sideband signals with suppressed carrier F i g. Figure 4 is an illustration of the waveforms of the outputs 28 and 30, their modulus the function generators on the basis of a lation envelope by 90 ° against each other phase sinusoidal Input signal generated output are shifted. With the help of these two signals signals, and the omnidirectional characteristic generates the

FIG. 5 shows a diagram of the circuit according to FIG. 35 a radiation diagram with a directional lobe, F i g. 2 supplied carrier wave input signal and around the antenna location with 30 revolutions of the modulated output from the circuit rotates per second.

Output signals, examples of antenna systems that are used in connection

F i g. 6 schematically an electrical circuit diagram of the phase shifter used with the system according to the invention and of the two types of radio 40 bar are the 47 898-VOR antenna of the Wilcox tion generators as well as Electric Company, Kansas City, Missouri, as well as the

F i g. 7 is a partial view of a bridge arm of that described in U.S. Patent 2,746,039 Circuit according to Fig. 2, from which the mutual antenna. Such antennas have a circular connection a function generator and a beam input terminal for receiving the on the AusVaraktordiode emerges. 45 output 20 of the AM modulator 12 appearing signal as well as two assigned to the variable phase signal

General description of the navigation system arranged input terminals to accommodate the two

Double sideband signals with suppressed carrier

Fig. 1 shows a VHF omnidirectional beacon, which is at the outputs 28 and 30 of the circuit beacon system in which, for example, a carrier 50 26 is present, the combined signals being the above frequency of 110 MHz is used. The discussed form a circumferential directional lobe, The output signal of the carrier wave generator 10 is The circuit 26 has four control inputs 32, 34,

an input of an AM modulator 12 is supplied. 36 and 38, which are connected to the outputs of function inputs Modulation signal having a frequency from generators 40, 42, 44 and 46 are coupled. As 9960Hz is generated by the signal source 14 and 55 is explained in more detail below, control the Function generators 40 to 46 connect the circuit 26 to one input of an FM modulator 16 placed. The 9960 Hz signal can be used as a subcarrier in such a way that the 110 MHz carrier receives the desired because it is pushed on by means of a 30 Hz modulation. The functional generalation signals a signal source 18 frequency-modulated gates operate as a function of the 30 Hz. According to Fig. 1, the subcarrier and 60 are the signal of the source 18, hereinafter referred to as primary 30 Hz modulation signal is referred to in the FM module signal. This primary signal becomes Iatorl6 combined and then fed to the AM modulator a phase shifter 48, which the signal 12 as a modulation signal for the 110 MHz carrier in two secondary signals with 90 ° phase difference fed. splits. The secondary signals are sinusoidal

At the output 20 of the AM modulator 12 there is a 65 and have the same frequency as the primary signal in the form of the 110 MHz carrier that carries the signal. One of the secondary signals appears on Output signal of the FM modulator amplitude output 50 of the phase shifter 48 and is to the is modulated, which in turn is coupled to a center frequency function generators 40 and 42, while

7 8

rend the other secondary signal at the output 52 of the inductor 110 is connected. The right bridge

Phase shifter 48 occurs and the DC voltage is applied to the functional via the HF choke 132

Generators 44 and 46 is coupled. fed to one side of the tunable

Because the modulation suppressor 22 is connected to the inductance 112. HF chokes

Formation of the suppressed 110 MHz carrier for 5 134, 136, 138 and 140 are possible with the control input

the antenna signal with variable phase used terminals 32 a, 34 a, 36 a and 38 a connected and

Instead of the bridge circuit 26, these terminals are coupled directly to the branches 62, 64, 54

to couple the generator 10, the round or 56. An HF choke 142 is in series with the

Beam antenna signal and the variable phase common return line. HF chokes 144, 146,

Antenna signal mutually determined in their phase, io 148 and 150 are, as illustrated, in the bridge

so that any carrier phase difference is avoided, ken switched on so that branches 58, 60, 66 and

which are controlled by the same signals as the intermediate modulator stages 68

could occur. branches 56, 54, 64 and 62, respectively.

The goniometer ^{Fig. 3 shows the} capacitance characteristic of an in

15 reverse biased varactor diode. By doing

F i g. 2 shows a schematic circuit diagram of the diagram between the cathode and anode of FIG

Bridge circuit 26, the input terminals 24 a diode applied reverse voltage as the abscissa, the

and 24 b, the output terminals 28 a and 28 b, initial capacitance of the diode as ordinate,

input terminals 30 α and 30 b, control input terminals Fig. 3 shows a non-sinusoidal input voltage

32 a, 34 a, 36 a and 38 a as well as a control terminal 20 voltage 151. The characteristic curve of the diode is loaded with 152

32 b, 34 b, 36 b, 38 b , which draws a common. The characteristic curve 152 is non-linear;

Forms return line. The terminal designation after if, however, the illustrated non-sinusoidal

F i g. 2 (reference number and index α or b) corresponds to a voltage applied to the diode, it is

the terminal designation according to Fig. 1, so that the speaking of the sine wave 154 is a sinusoidal channel

F i g. 1 and 2 easily related to one another 25 change in capacitance is obtained. The diagram allows

can be. know that the applied voltage 151 is periodic

The circuit 26 is provided with two bridges be, but must have half periods of unequal duration and undie four branches and a α with the terminals 24 of the same instantaneous amplitude to a and 24 b coupled common input Open sinusoidal variation of the capacity of Varaktorweisen. The two bridges have separate emitting diodes.

gears through terminals 28 a, 28 & or 30 a, The carrier wave is modulated with the help of 30 & are shown. The bridge circuit 26 belongs to the left bridge by repeated abduction Branches 54, 56, 58 and 60, equal to the right bridge and detuning the bridges, as in the the branches 62, 64, 66 and 68. The following is explained in more detail in each arm. The control an electrically controllable control impedance, the Va- 35 of the two bridges between the balanced actuator diodes 70, 72, 74, 76, 78, 80, 82 and 84 in the state and the detuned state takes place through the arms 54 to 68 include. In the branches of the change in the capacity of the bridge branches, and Both bridges are also capacitors, although they are electronically with the help of zeitmit variable control signals connected in series to the respective diodes which are sent to the varactors. These capacitors have 86, 88, 90, 92, 40 diodes in the bridge arms. Around 94, 96, 98 and 100 designated, which in the arms 54 with a sinusoidal modulation of the carrier wave to 68 are arranged. To effect carrier suppression, the capacitance must

A tunable inductance 102 is parallel to the bridge arms with a frequency of 30 Hz,

to the common bridge entrance. The arms that are generated at the frequency of the source 18

54, 56, 62 and 64 are at the nodes 104 45 th primary signal coincides, sinusoidally shaped

and 106 with one side of the entrance that arms are changed.

58, 60, 66 and 68 at node 108 with FIG. Figure 3 shows the desired capacity variance Side of the entrance connected. Adjustment of the varactor diode in the event that the zubare Inductors 110 and 112 are parallel to the additional bridge arm capacitance with respect to the wire Exits of the bridges. The inductance 110 50 capacity of the diode is negligible. Consequently is in series with two variable inductances, the change in diode capacitance is sinusoidal 114, two coupling capacitors 116 and one illustrated. In practice, however, the Winding of a balun 118 switched. Capacity of the DC voltage in in each branch Similarly, the inductance is provided in the coupling capacitor and blocking provided in series with two variable inductances 120, two stray capacitances 55 a diode capacitance change er coupling capacitors 122 and the one winding that deviates from the sinusoidal shape and such a symmetry transformer 124. The symmetry is selected that the total capacitance of each Transmitter 118 and 124 have experienced a sinusoidal change in a translation bridge branch, ratio of 1: 1. The secondary winding of each To simplify the illustration, however, is in front of the transformer is, as illustrated, with the 60 lying on the assumption that the bridge arm capacitance relevant output terminals. negligible compared to the capacitance of the diode

A fixed preload (direct voltage) is bar.

from an unillustrated power source between- The function generators that provide the required see a positive terminal 126 and the common non-sinusoidal control signals for the bridge same return line or ground. The equals 65 are shown in FIG. 6 shown. The phase shifter voltage is the left bridge of the circuit 26 48 is on the left of the schematic above the conductor 128 and the RF choke 130 illustrated in the pulled position. He's in conventional leads that run with one side of the tunable way and has two input terminals

9 10

156, which is connected to the output of the 30 Hz source 18. The circuit of the function generator 44 is similarly coupled are. The Hch applied to terminals 156 is that described above for generator 46 The primary signal is designed using the i? C component circuit. The difference between both The phase shifter in the two secondary signals from the generators is in the polarity of the converted. The one secondary signal occurs at the 5 terminals 186 'and 188' applied voltage as well Output line 52 and has opposite the polarity of the diodes 190 'to 198'. Furthermore Primary signal has a phase lead angle of 45 °. the circuit of the generator 44 corresponds to that The other secondary signal appears at the output of the generator 46 including the dimensioned output line 50 and, with reference to the primaryization of resistors 158 'to 184'. The secondary signal a phase lag angle of 45 °. io winding of the output transformer 204 'is with the

Since the circuit of the function generators 40 control input terminals 36 α and 36 b of the bridge

and 44 as well as the generators 42 and 46 are connected to a circuit 26.

true, are shown in FIG. 6 only the generators 44 and FIG. 4 shows the input and output signals 46 shown schematically. The function generator of the function generators. The sine wave 206 ent-46 has a series of resistors 158, 160, 15 which corresponds to the outputs 50 or 52 of the 162, 164, 166, 168, 170, 172, 174, 176, 178, 180, phase shifter 48 appearing signal. Would be 182 and 184, both of which are present at outputs 50 and 52 in the manner illustrated connected to each other and illustrated with the output line signals, these would be at 90 ° against -52 of the phase shifter 48 are coupled. That be out of phase with each other. Accordingly Resistor 168 is connected in the form of two in series. 4 the phase relationship between the siteter Resistances illustrated, of which the gnal at output 52 and that of the function is adjustable and serves as a trimmer. In these generators 40 and 42 generated signals or the Arrangement forms the adjustable section of the phase relationship between the signal at the output Resistor 168 is part of an automatic 52 and that of the function generators 44 and Detect error correction device to compensate for 25 46 signals emitted. As can be seen The two A-function generators 40 and generate lobe shape errors during operation of the navigation system gation system. 44 a signal 208, the phase of which with that of the

A DC supply voltage is matched to the radio sinusoidal secondary signal 206, tion generator 46 via terminals 186 and 188. The signal 208 has a broad, relatively applied, of which terminal 186 is negative and the 30 flat, positive part 210 and a relatively terminal 188 is positive. Solid state diodes (half-tipped negative part 212, which, relative to the Beleiter diodes) 190, 192, 194, 196 and 198 are in the drawing line or axis 214, larger amplitude in the manner illustrated with the resistor series. The part 210 has a longer duration than the part coupled and together with it form the waveform 212, so that unequal half-periods arise across the part of the circuit. The output signal of the 35 probably the period of the signal 208 with the diode 190 controls a field effect transistor 200 with those of the sinusoidal signal 206 matches. Source 200 a, sink 2006 and gate 200 c. The field signal 216 of one of the B-generators 42 or effects transistor 200 in turn controls a pnp- 46 corresponds to signal 209, with the exception of transistor 202, which gives the generator output signal to an output transformer 204 that is 180 ° from one another. The secondary 40 are out of phase. It follows from this that the development of the transformer 204 is applied to the control input signals of the function generators 40 and 42, input terminals 38a and 386 of the bridge circuit are shifted by 180 ° with respect to one another and are in process. in the same way the output signals of the radio

If as a varactor diode in each bridge branch tion generators 44 and 46 a mutual phase

a diode of the type Philco V-4091 is used and have a sensor shift of 180 °. Furthermore, since the

is the additional capacity of the bridge arm at the outputs 50 and 52 of the phase shifter

negligible compared to the diode capacitance, 48 secondary signals appearing a 90 ° phase

If an output signal has the desired wave difference, the function generators have

form with resistors 158 to 184 obtained, the 40, 44, 42 and 46 relative phase angles of 0, 90,

are dimensioned as follows: 50 180 or 270 °.

Ä158 200kOhm mode of operation

^{R 160 52> 3 kOnm} The function of each of the bridge branches of the two

^{R 162} 1 °> ⁵ kOhm ₅₅ bridges of the circuit 26 results easily

R164 11.3 kOhm from Fig. 7. There is one of the rest of the circuit

R 166 28 kohm separate branch 56 illustrated so that the

R jgg 39 J ₃ J ₃ 64 kohm Effect of the varactor diode 72 easy to understand

" ₁₇ " ₁ _, _n is. A DC voltage source 218 is between the

^{υ 1;> kUnm} 60 positive terminal 126 and the negative

^ 172 12.4 kOhm terminal or common return line 38 b dar-

R174 13.3 kOhm. The secondary winding of the output trans-

R 176 15.0 kohm converter 204 of the function generator 46 is connected to the

/ 2178 _ 17 4kOhm terminals 380 and 38 a connected. the clamp

η _18n '_ _, 65 38 b also forms the common return line for

^Λ | ^ö "^{y> uy kLmm} the three further functions not shown in FIG. 7

^{R 182 32} > 4 kOhm tion generators.

R 184 100kOhm The source 218 and the secondary winding of the

Transformer 204 are functionally in series, so that the resulting potential difference between the cathode and anode of the diode 72 corresponds to the sum of the potential emitted by these two voltage sources. The signal generated in the secondary winding of the transformer 204 is alternately rectified or opposed to the constant voltage output by the source 218. This also follows without further ado from FIG. 4, since the baseline or reference axis 220 of signal 216 represents the value of the constant voltage provided by source 218. In this way, this constant negative voltage provides the varactor diode with a fixed bias in the reverse direction, which is varied when the function generator alternately counteracts or supports the source 218. In the middle of the period of the signal 216, which coincides in time with the zero crossing of the sinusoidal secondary signal 206 , an in FIG. 3 voltage shown at 222 that the capacitance of the diode assumes a value which is indicated at 224 on the capacitance axis of the diagram. The capacitance value at 224 is equal to the mean value of the capacitance of the diode in the transition between the maximum value 226 and the minimum value 228.

The output signal of the function generator according to FIG. 7 has the task of varying the voltage applied to the diode 72 between a negative maximum value (230 in FIG. 4) and a negative minimum value (232 in FIG. 4). According to the characteristic according to FIG. 3, this results in a sinusoidal change in the capacitance of the diode 72 within a period which corresponds to the period of the output signal on the secondary winding of the transformer 204. The sinusoidal fluctuation in the diode capacitance corresponds in frequency to the secondary signal 206 occurring at the output 52 of the phase shifter 48 , the frequency of which in turn corresponds to the frequency of the 30 Hz primary signal from the source 18 .

As a result of the presence of the capacitor 88 , no direct current or a significant portion of the 30 Hz current flows to the node 106 or via the HF choke, so that the effect of the function generator and the source 218 on the diode 72 remains limited. The only current flowing is the residual current, which flows through the reverse-biased conductivity junction of the diode. However, the capacitor 88 does not prevent the carrier wave that reaches the branch at the node 106 from traveling via the branch 56.

According to FIG. 2, the cathode of diode 72 is connected to the output of the bridge at the upper end of inductor 110 . As a result, a path is formed for the high-frequency carrier wave, which runs from the input of the bridge via the sinusoidally fluctuating capacitance in the form of the diode 72 to the bridge output.

Looking at the operation of the overall circuit, it emerges that the capacities of the various branches of the two bridges are constantly changed sinusoidally, which in turn causes the bridges to be detuned first in one direction and then in the other direction. Together, this has the effect that the high-frequency carrier in each bridge is divided into two sidebands which contain the 30 Hz modulation information impressed on the sidebands by means of the varactor diodes. The carrier is suppressed so that only a double sideband signal remains at each bridge output. As a result of the 90 ° phase shift between the two secondary signals at the outputs 50 and 52 of the phase shifter 48 , the modulation envelopes of these signals have a mutual phase shift of 90 °.

In Fig. 5, the input carrier shaft is shown at 236 . The carrier suppressed output signals obtained at bridge outputs 28 and 30 are shown at 238 and 240 . The dashed lines according to FIG. 4 connect the same points in time of the time axes of the respective waveforms and clearly show that the HF double-sideband signals are constantly in phase with the HF carrier or are phase-shifted by 180 ° with respect to this. So lets z. For example, see waveform 238 that at 242 a phase reversal of the RF signal occurs. If waveform 238 were to run for a longer period of time than shown in FIG. 5, it would be seen that a phase reversal also occurs at 244 and 246 . Similarly, waveform 240 undergoes an RF phase reversal at 248 and 250. The phase reversal points of waveform 238 coincide in time with the times when the bridge with branches 54, 56, 58 and 60 is aligned. Similarly, the turning points of waveform 240 correspond in time to the moments in which the bridge with arms 62, 64, 66 and 68 is in the balanced state. For waveform 238 , the portion of the wave between points 244 and 242 corresponds to detuning the bridge in one direction, while the portion of the waveform between points 242 and 246 indicates that the bridge has passed through the balanced state and in the opposite direction Direction is out of tune. The same applies to the other bridge of circuit 26 corresponding to the phase reversals occurring at points 248 and 250 of waveform 240.

From Fig. 5 it can be seen that the modulation envelopes of waveforms 238 and 240 are 90 ° out of phase with one another. The peak amplitudes of the envelope of waveform 238 occur at 252 and 254 , while the amplitude peaks of waveform 240 appear at 256, 258 and 260 . This 90 ° phase shift between the modulation envelopes of the two double sideband output signals of the circuit 26 result from the 90 ° phase shift between the two 30 Hz secondary signals that are applied to the function generators 40, 42 and 44, 46 via the phase shifter 48 . The modulation envelopes contain the 30 Hz modulation information. The carrier is added by means of the VOR antenna.

The tunable inductor 102 at the input of circuit 26 is tuned to resonate with a capacitance value equal to the average capacitance of one of the varactor diodes plus twice the smallest capacitance of the diode. The mean capacity is shown in FIG. 3 indicated at 224 , while the smallest capacitance is shown at 228 on the capacitance axis of the diagram. It is assumed that all varactor diodes of circuit 26 have similar characteristics.

The variable inductances 110 and 112 that are parallel to the bridge outputs are so tuned that they come into resonance with a capacitance value shown in FIG. 3 shown at 228 and corresponds to the smallest capacitance of one of the varactor diodes. Any pair of mutable Inductors 114 and 120 are at resonance with a capacitance value corresponding to the capacitance

224 according to FIG. 3 matched, which corresponds to the average capacitance of one of the varactor diodes. The vote the various inductances can be made during the operation of the plant will. Also every setting of the function generators by changing the value of the resistance 168 (or 168 ') can take place during operation in order to ensure that the system works optimally.

1 sheet of drawings

Claims (13)

Patent claims: 1. Electronic goniometer for a radio beacon with a carrier source, generators for generating sinusoidal low-frequency and medium-frequency modulation signals, a frequency modulator for combining the two modulation signals to form a combined modulation signal, an amplitude modulator for modulating the carrier with the combined modulation signal, a device for generating an antenna arrangement from omnidirectional antenna and crossed directional antenna system with carrier modulated with the aid of the resulting modulation signal and two sideband signals with suppressed carriers, the modulation envelopes of which are shifted against each other by a predetermined phase, characterized by a modulation suppressor (22) for generation a modulation-free carrier (236) in phase with the modulated carrier on the antenna assembly (20), d he carrier (20) is obtained directly from the modulated carrier for the omnidirectional antenna, four function generators (40, 42, 44, 46) for the direct generation of distorted control signals (208, 216) of the modulation frequency, a double bridge amplitude modulator (26) with the control signals (208, 216) applied varactor diodes (70 to 76 or 78 to 84) as impedances dependent on these control signals in the bridge branches (54 to 60 or 62 to 68) for generating two sinusoidal sideband signals with suppressed carriers of predetermined relative phase shifts (0 or 90 °), the distorted control signals (208, 216) being shaped in such a way that, taking into account the non-linear characteristics of the varactor diodes (70 to 76 or 78 to 84), sinusoidal sideband oscillations arise. 2. Electronic goniometer according to claim 1, characterized in that the function generators (40, 42, 44, 46 ) contain waveformers (158 to 198 and 158 ' to 198') which give the control signals an amplitude curve that compensates for the non-linear characteristic of the varactor diode ( Fig. 6). 3. Electronic goniometer according to claim 2, characterized in that in the branches (54 to 60 or 62 to 68) of the varactor diode bridge (26) capacitors (86 to 92 or 94 to 100) are provided for blocking direct current voltage. 4. Electronic goniometer according to claim 1, characterized in that the function generators (44, 46 and 40, 42) and phase shifter (48) shift the phases of the control signals against each other in such a way that the impedances dependent on them in the bridge branches of the two bridge circuits (54 to 60 and 62 to 68) align the bridges alternately. 5. Electronic goniometer according to claim 4, characterized in that the Control signals are periodic signals with the same period duration that with the varactor diodes (70 to 76) of one bridge circuit (54 to 60) first function generators (44, 46) are coupled, which emit first control signals which have such a mutual phase relationship that one bridge circuit is briefly balanced with a clock of half the period and that second function generators (40, 42) are coupled to the varactor diodes (78 to 84) of the other bridge circuit (62 to 68) , which output second control signals that the other bridge circuit is also briefly synchronized in the cycle of half the period. 6. Electronic goniometer according to one of claims 4 and 5, characterized in that the phase shift between the first and second caused by the phase shifter (48) Control signals is equal to the phase shift between the modulation envelopes. 7. Electronic goniometer according to one of claims 5 and 6, characterized in that the first and second function generators (44, 46 and 40, 42) each have two control signals issue, which are each 180 ° out of phase with each other. 8. Electronic goniometer according to claim 7, characterized in that the two bridge circuits each have four bridge branches (54 to 60 or 62 to 68) which are acted upon in pairs by one of the control signals. 9. Electronic goniometer according to one of claims 1 to 8, characterized in that the modulation suppressor (22) for generating an input signal of constant amplitude a includes automatic gain control. 10. Electronic goniometer according to one of claims 1 to 9, characterized in that the function generators (40, 42, 44, 46) contain an adjustable resistor (268) to compensate for lobe errors. 11. Electronic goniometer according to one of claims 1 to 10, characterized in that the varactor diode bridge (26) contains an inductance (102) which can be tuned to the mean plus twice the smallest capacitance. 12. Electronic goniometer according to one of claims 1 to 11, characterized in that the varactor diode bridge (26) contains inductances (110, 112) which can be tuned to the smallest capacitance of the diodes and are parallel to the bridge outputs. 13. Electronic goniometer according to one of claims 1 to 12, characterized in that the varactor diode bridge (26) contains a pair of inductances (114, 120) which can be tuned to the average capacitance of the diodes in each input circuit.