WO2019105755A1 - Device for receiving linearly polarised satellite signals - Google Patents

Abstract

The invention relates to a device (10; 100) for receiving linearly polarised satellite signals, comprising at least one first and one second decoupling probe (14; 16), which are oriented at an angle to one another and project into a waveguide (12), and each provide a linearly polarised input signal, and comprising a signal processing unit (13) for processing the two input signals. In order to further develop the device (10; 100) in such a way that it permits a noise-immune electronic correction of a polarisation squint angle, according to the invention: the signal processing unit (13) has a first combination element (22), which generates opposing elliptically polarised high-frequency signals from the linearly polarised input signals; and the signal processing unit (13) has controllable signal conversion arrangements (32, 38), which convert the elliptically polarised high-frequency signals into elliptically polarised intermediate-frequency signals, wherein the intermediate-frequency signals have a predefinable phase difference in relation to one another; and the signal processing unit (13) has a second combination element (66), with the aid of which the elliptically polarised intermediate-frequency signals can be combined to form a linearly polarised output signal.

Description

 DEVICE FOR RECEIVING LINEAR POLARIZED

 SATELLITE SIGNALS

The invention relates to a device for receiving linearly polarized satellite signals, with a first and a second coupling probe, which are aligned at an angle to each other and project into a waveguide, wherein the first coupling probe provides a first linearly polarized input signal and wherein the second coupling probe a second linearly polarized input signal, and with a signal processing device for processing the two input signals.

Such devices are used to receive linearly polarized signals transmitted by geostationary satellites, in particular in a frequency range from 10.7 GHz to 12.75 GHz. The satellite signals are linearly polarized, with two geostationary satellites often transmitting two different signals in two identical polarization planes in the identical frequency range, in particular on identical carrier frequencies. One of the polarization planes is usually referred to as vertical polarization plane and the other polarization plane is usually referred to as horizontal polarization plane. The satellite signals are received by means of two output probes, which protrude into a waveguide and are oriented at an angle to one another, preferably perpendicular to one another.

Upon receipt of a linearly polarized satellite signal results in the

Difficulty that the dedicated Auskoppelsonde should ideally be aligned in the plane of polarization of the desired satellite signal. Otherwise, the decoupling probe can only record a fraction of the energy available at the reception location, and the decoupling probe receives not only a portion of the satellite signal which is desired per se, but also a portion of the satellite signal which is present in the other polarization signal. be transmitted at the level of This leads to a deterioration of the signal / noise ratio of the signal provided by the Auskoppelsonde.

The angular offset between the polarization plane of the desired satellite signal and the plane in which the decoupling probe provided for receiving this satellite signal is aligned is usually referred to as the polarization error angle.

In order to keep the polarization error angle as low as possible and ideally to achieve a polarization error angle of 0 °, receiving devices are known in which the coupling probes can be mechanically rotated together with the waveguide into which they protrude around the longitudinal axis of the waveguide. This allows a mechanical adjustment of the receiving device. If the receiving device is operated stationary and only is to receive signals from a single geostationary satellite, such an adjustment can be made once during the installation of the receiving device. Normally, a further adjustment is then no longer required.

A difficulty arises if the receiving device alternately signals from different geostationary satellites to be received. For this purpose, the receiving device must be aligned with the respective satellite, whereby a correction of the polarization error angle must also be undertaken, since the geostationary satellites occupy different orbital positions which result in different polarization error angles.

A further difficulty arises in the case of reception devices which are not fixedly installed but are operated alternately at different locations. It has been shown that different polarization error angles occur at different locations, even with respect to the same geostationary satellite, which must be corrected in each case. Becomes If the receiving device is mechanically adjusted during each change of location or satellite, this leads to a considerable susceptibility to interference due to the mechanical loading of the receiving device.

A particular difficulty arises in receiving devices which are mounted on a land or water vehicle and are in motion during operation. In a permanent movement of the receiving devices, a continuous correction of the polarization error angle is required, which can not be practically achieved by a mechanical adjustment.

Instead of mechanically rotating the receiving device, for example by means of an electric motor, an electronic correction of the polarization error angle is proposed in US Pat. No. 5,568,158. In this case, the input signals, which are provided by two coupling probes aligned perpendicular to one another, are processed by means of a signal processing device. The input signals are amplified and attenuated by means of controllable attenuators and then combined, wherein in addition the phase of one of the input signals by means of a phase shifter can be shifted by 180 °. The frequency of the combination signal resulting from the combination of the processed input signals is then reduced with the aid of a down converter, so that an output signal with an intermediate frequency is present, which can then be fed via a coaxial cable to a receiving device.

An electronic correction of the polarization error angle eliminates the problems resulting from a mechanical adjustment of the receiving device. However, it has been shown that the electronic correction known from US Pat. No. 5,568,158 by means of controllable attenuators is frequently susceptible to interference and poorly controllable in practice.

It is therefore an object of the present invention to develop a device of the type mentioned at the outset in such a way that it provides a simple and trouble-free operation. insensitive electronic correction of the polarization error angle.

This object is achieved according to the invention in a device of the generic type in that the signal processing device has a first combination element that generates a left-handed and a right-handed elliptically polarized high-frequency signal from the two linearly polarized input signals, and that the signal processing device for each elliptically polarized high-frequency signal having a controllable signal conversion arrangement, wherein the high-frequency signals by means of Sigalumsetzanordnungen in mutually opposite elliptically polarized Zwischenfrequenzsignale be implemented, the intermediate frequency signals relative to each other having a predetermined phase difference, and in that the signal processing means comprises a second combination element, wherein means of the second combination element, the two elliptically polarized intermediate frequency signals can be combined to form a linearly polarized output signal nd.

In the present case, an elliptically polarized high-frequency or intermediate-frequency signal is understood to mean a signal which corresponds to an electromagnetic wave whose deflection from the rest position circulates on an ellipse in a plane oriented perpendicular to the propagation direction of the shaft. The semiaxes of the ellipse may be the same or different, so that the elliptical polarization in the present case also comprises a circular polarization, in which the deflection of the electromagnetic wave in a plane oriented perpendicular to the propagation direction rotates on a circle. The term "elliptical polarization" therefore also encompasses a circular polarization in the present case.

The idea flows into the invention that a linearly polarized satellite signal can be completely obtained from the received signals which are provided by two coupling-out probes aligned in an angle by the linearly polarized input signals of the coupling-out probes are combined to form a left-handed elliptical, in particular circularly polarized, high-frequency signal and a right-handed elliptical, in particular circularly polarized, radio-frequency signal and these counter-rotating elliptic, in particular circularly polarized signals are converted to intermediate-frequency signals with predefinable phase difference and the converted elliptical, in particular circular polarized intermediate frequency signals are then combined again to form a linearly polarized output signal. The required phase difference of the elliptical, in particular circularly polarized intermediate frequency signals can be achieved by optimizing the

Determine the signal / noise ratio of the output signal.

The device according to the invention makes possible an interference-free electronic correction of the polarization error angle. In a first step, the two linearly polarized input signals of the coupling probes are converted into two mutually opposite elliptical, in particular circularly polarized, high-frequency signals. For this purpose, the signal processing device has a first combination element. In order to generate a first elliptically, in particular circularly polarized, high-frequency signal, for example the left-handed elliptical, in particular circularly polarized, high-frequency signal, the first combining element effects a phase shift of the first input signal by 90 ° and subsequently forms a weighted sum of the phase-shifted quadrature first input signal and the unchanged in its phase second input signal. To generate the second elliptical, in particular circularly polarized, high-frequency signal, that is, for example, the right-handed elliptical, in particular circularly polarized, high-frequency signal, the first combination element effects a phase shift of the second input signal by 90 ° and then forms a weighted sum from the second input signal and phase-shifted by 90 ° the first input signal unchanged in its phase. In the case of summation, the weighting of the first and second input signals, which are phase-shifted by 90 ° and unchanged in their phase, can be carried out in such a way that the signals are combined with the same weighting or with different weightings. A Equal weighting of the signals leads to a special case of a circular polarization of the sum signal, whereas a different weighting results in a non-circular elliptical polarization of the sum signal.

Subsequently, the mutually opposite elliptical, in particular circularly polarized, high-frequency signals are converted by means of controllable signal conversion arrangements into mutually opposite elliptical, in particular circularly polarized, intermediate frequency signals with a predefinable phase difference. For this purpose, at least one signal conversion arrangement can also perform a predefinable phase shift in addition to the frequency conversion, so that the intermediate frequency signals have a predefinable phase difference relative to one another.

Both signal conversion arrangements preferably also carry out a phase shift in addition to the frequency conversion. For example, a first controllable signal conversion arrangement can be supplied with the left-handed elliptical, in particular circularly polarized, high-frequency signal which is converted by the first signal conversion arrangement into a left-handed elliptical, in particular circularly polarized, phase-shifted intermediate frequency signal and a second controllable signal conversion arrangement can be elliptical , in particular circularly polarized high-frequency signal are supplied, which is converted by the second signal conversion arrangement in a right-handed elliptical, in particular circularly polarized Zwischenfre- frequency signal with a changed phase.

In a further step, the mutually opposite elliptical, in particular circularly polarized intermediate frequency signals are combined with the aid of a second combination element to form a linearly polarized output signal.

It has now been found that by changing the phase shift effected by the at least one controllable signal conversion arrangement, the signal / noise ratio of the linearly polarized output signal can be optimized, wherein the output signal corresponds to the satellite signal transmitted in a first polarization plane, for example the satellite signal transmitted in the horizontal polarization plane. The output signal has virtually no portions of the satellite signal which is transmitted in the second polarization plane orthogonal to the first polarization plane, for example the vertical polarization plane. The portions of the intrinsically interfering second satellite signal are extinguished by the superposition of the opposite elliptical, in particular circularly polarized intermediate signals, wherein the cancellation can be recognized from the fact that the output signal has an optimum signal / noise ratio.

In electromotively rotatable receiving devices, a correction of the polarization error angle can be achieved by optimizing the signal / noise ratio of the output signal provided by the receiving device by mechanical rotation of the device. In the device according to the invention, a mechanical rotation is not required, but rather the signal / noise ratio of the output signal can be optimized by changing the phase difference of the opposing elliptical, in particular circularly polarized intermediate frequency signals.

As already mentioned, the first combination element is set up such that a left-rotating elliptically polarized high-frequency signal and a right-rotating elliptically polarized high-frequency signal can be generated from the two linearly polarized input signals. It is particularly advantageous if a left-handed circularly polarized high-frequency signal and a right-handed circularly polarized high-frequency signal can be generated by means of the first combination element from the two linearly polarized input signals. As already mentioned, this can be achieved by balancing the first and second input signals which are phase-shifted by 90 ° and whose phase is unchanged in their summation. To control the signal conversion arrangements, the signal processing device advantageously has a control unit.

Preferably, the use of the control unit allows at least one signal conversion arrangement to provide a special phase control signal.

It is advantageous if the two signal conversion devices each carry out a phase shift, wherein the first signal conversion arrangement can be provided with a first phase control signal corresponding to a first phase shift angle, and wherein the second signal conversion arrangement can be provided with a second phase control signal second phase shift angle corresponds.

The phase shift angles are not necessarily identical. It may in particular be provided that the two phase shift angles differ only in their sign but not in their magnitude, so that the left-handed circularly polarized signal in its phase, for example by a phase angle + F and the clockwise circularly polarized signal about the phase angle - F is shifted, where F can assume a value between 0 ° and 90 °.

The control unit is preferably a microprocessor is used.

The controllable signal conversion arrangements are preferably configured as downconverters, wherein at least one signal conversion arrangement has a phase locked loop which can be acted upon by a phase control signal. Down-converters with a phase-locked loop, which is also referred to as a phase-locked loop, are known per se to the person skilled in the art. These are standard circuits that are produced inexpensively for a wide variety of uses in large quantities. By means of a phase control signal, the signal converted by the down converter can be shifted in its phase. Both controllable signal conversion arrangements preferably have a phase-locked loop, which can be acted upon by a phase control signal.

It is favorable if the signal conversion arrangements each form a single integrated circuit. The integrated circuit can form a compact electrical component which can be produced inexpensively in large quantities.

It may, for example, be provided that the phase locked loop of the at least one signal conversion arrangement is connected to an oscillator circuit which provides an oscillator signal to the phase locked loop and that the phase locked loop has a loop filter which can be acted upon by a phase control current. Phase-locked loops with a loop filter are known per se to those skilled in the art and therefore require no further explanation in the present case. The phase control current represents a phase control signal with the aid of which a phase shift can be achieved. The application of a phase control current, that is, the injection of a phase control current into the loop filter, results in a phase shift of the oscillator signal, which in turn results in a phase shift of the intermediate frequency signal provided by the down converter.

It is favorable if the phase locked loop is assigned a controllable current supply element which provides a phase control current to the loop filter of the phase locked loop.

Preferably, the current supply member is controllable by a control unit of the signal processing device.

It can be provided that the current supply member is designed as a current pulse encoder or digital / analog converter, which are acted upon by the control unit with a control signal. In an advantageous embodiment of the invention, the controllable signal conversion arrangements each have a phase-locked loop, wherein the phase-locked loops are connected to a controllable DDS synthesis circuit (direct digital synthesis circuit), which provides the phase-locked loops each with a reference clock signal, wherein the frequencies of the reference clock signals are identical and the phases of

Reference clock signals have a predetermined phase difference (phase offset). Controllable DDS synthesis circuits are known per se to those skilled in the art and therefore require no further explanation in the present case.

By means of a controllable DDS synthesis circuit, two phase control signals in the form of two reference clock signals with identical frequency and predefinable phase offset can be generated. One of the two reference clock signals may be applied to the phase locked loop of a first buck converter, and the other reference clock signal may be applied to the phase locked loop of a second buck converter. This has the consequence that the down-converters provide intermediate frequency signals which differ in their phase in a predeterminable manner.

Preferably, the DDS synthesis circuit is controllable by a control unit of the signal processing device.

The down-converters preferably each have a mixing element, wherein the frequency of the elliptical, in particular circularly polarized, high-frequency signals can be converted into an intermediate frequency by means of the mixing elements.

The intermediate frequency is preferably 0.95 GHz to 2.15 GHz.

It is advantageous if the signal processing device has an amplifier with controllable amplification for each linearly polarized input signal. This makes it possible to independently amplify the linearly polarized input signals provided by the coupling probes in a predeterminable manner. For test purposes, the amplifiers can be switched off alternately. It is favorable if the signal processing device has an amplifier control element for controlling the amplifiers.

Preferably, a control signal can be provided to the amplifier control element by a control unit.

In an advantageous embodiment of the invention, the signal processing device has a controllable level control for each elliptical, in particular circularly polarized intermediate frequency signal. The level control can be designed, for example, as a controllable attenuator or as a controllable gain member. By means of the level control, undesired level differences of the two intermediate frequency signals can be eliminated. In particular, it can be ensured by means of the controllable level adjusters that the levels of the intermediate frequency signals provided to the second combination element are the same, so that identical input levels are present at the inputs of the second combination element. This in turn leads to an optimal amplitude of the output signal, whereby unwanted signal components are suppressed.

Conveniently, the level controllers of a control unit, a control signal can be provided.

As mentioned, it is advantageous if the levels of the elliptical, in particular circularly polarized intermediate-frequency signals can be set to identical values, since an output signal with high amplitude and small amounts of unwanted signals can thereby be achieved.

In an advantageous embodiment of the invention, a filter element is arranged downstream of the second combination element. With the help of the filter element unwanted spectral components of the output signal can be removed.

The filter member is preferably formed as a low-pass or bandpass. In order to be able to provide control signals to individual components of the signal processing device that depend on the power of the output signal, it is advantageous if the signal processing device has a

Power detector, which is acted upon by the second combination member with a signal to be measured, which corresponds to the output signal of the Vorrich-, and a control unit of the Signalverarbeitungseinrich- tion of the measured power corresponding measured value provides.

With the help of the power detector, for example, the above-mentioned level control can be controlled so that the amplitudes of the voltage applied to the inputs of the combination element intermediate frequency signals are equal.

The following description of advantageous embodiments of the invention is used in conjunction with the drawings for further explanation. Show it :

1 shows a block diagram of a first advantageous embodiment of a device for receiving linearly polarized

 Satellite signals;

FIG. 2 shows a block diagram of a second advantageous embodiment of a device for receiving linearly polarized

 Satellite signals.

1 shows a first advantageous embodiment of an inventive device for receiving linearly polarized satellite signals is shown schematically and overall occupied by the reference numeral 10. It has a waveguide 12 and a signal processing device 13. In the waveguide 12 protrude a first Auskoppelsonde 14 and a second Auskoppelsonde 16 into it. The two Auskoppelsonden 14, 16 are at an angle to each other, preferably aligned perpendicular to each other. The first outcoupling probe 14 provides a first controllable amplifier 18 with a first linearly polarized input signal which is amplified by the first controllable amplifier 18 and fed to a first input 20 of a first combination element 22. The second decoupling probe 16 provides a second controllable amplifier 24 with a second linearly polarized input signal, which is amplified by the second controllable amplifier 24 and fed to a second input 26 of the first combining element 22.

The first combining element 22 generates from the two linearly polarized input signals a left-rotating elliptical, in particular circularly polarized, high-frequency signal which is fed via a first bandpass 28 to a signal input 30 of a first controllable signal conversion arrangement 32. In addition, the first combination element 22 generates a right-handed elliptical, in particular circularly polarized, high-frequency signal which is fed via a second bandpass 34 to a signal input 36 of a second controllable signal conversion arrangement 38.

To generate the left-rotating elliptical, in particular circularly polarized, high-frequency signal, the first combining element 22 phase-shifts the first linearly polarized input signal applied at the first input by 90 ° and subsequently forms a weighted sum from the phase-shifted first linearly polarized input signal and the voltage applied to the second input 26, in its phase unchanged second linearly polarized input signal. The sum of the two signals forms the levorotatory elliptical, in particular circularly polarized, high-frequency signal.

To generate the clockwise elliptical, in particular circularly polarized, high-frequency signal, the first combining element 22 performs a phase shift of the second linearly polarized input signal applied to the second input 26 and subsequently forms a weighted sum from the phase-shifted second linearly polarized input signal and the voltage applied to the first input 20, unchanged in its phase first linearly polarized input signal. The sum of the two signals forms the clockwise-rotating elliptical, in particular circularly polarized, high-frequency signal.

In the case of summation, the weighting of the first and second input signals, which are phase-shifted by 90 ° and their phase unchanged, can take place in such a way that the signals are summed with the same weighting or with different weightings. Equal weighting of the signals results in a special case of circular polarization of the high frequency signal, and differential weighting results in a non-circularly elliptically polarized high frequency signal.

The first combination element 22 can be designed, for example, as a directional coupler or as a 3 dB hybrid coupler.

The first controllable signal conversion arrangement 32 is designed as an integrated circuit having a first down converter 33, which has a first mixing element 35 and a first phase-locked loop 37 (phase-locked loop) with a first loop filter 47. With the aid of the first controllable signal conversion arrangement 32, the left-handed elliptical, in particular circularly polarized, high-frequency signal is converted into a counter-clockwise elliptical, in particular circularly polarized, intermediate signal, wherein a predetermined first phase shift is simultaneously carried out in accordance with a first phase control current a control input 39 of the first controllable Signalumsetzanordnung 32 is applied. The first phase control current forms a first phase control signal, which is provided to the first loop filter 47 of the first phase locked loop 37.

The second controllable signal conversion arrangement 32 is designed as an integrated circuit having a second down converter 40, which has a second mixer 41 and a second phase locked loop 43 (phase-locked loop) with a second loop filter 53. With the aid of the second controllable signal conversion arrangement 32, the clockwise rotating elliptical, in particular circular polarized high-frequency signal converted into a right-handed elliptical, in particular circularly polarized intermediate signal, at the same time a given second phase shift is carried out according to a second phase control current applied to a control input 45 of the second controllable Signalumsetzanordnung 38. The second phase control current forms a second phase control signal, which is provided to the second loop filter 53 of the second phase locked loop 43.

The intermediate frequency of the elliptical, in particular circularly polarized intermediate frequency signals is 0.95 GHz to 2.15 GHz.

To achieve the first phase shift, the first phase control current provided at the control input 39 of the first controllable signal conversion arrangement 32 is coupled into the first loop filter 47 of the phase locked loop 37 of the first controllable signal conversion arrangement 32. The phase-locked loop 37 is provided by an oscillator circuit 46 with an oscillator signal. By coupling the first phase control current, there is a phase shift of the oscillator signal and this in turn has the result that the left-handed elliptical, in particular circularly polarized, intermediate frequency signal provided by the first controllable signal conversion arrangement 32 has a first phase shift.

To achieve the second phase shift, the second phase control current provided at the control input 45 of the second controllable signal conversion arrangement 38 is coupled into the second loop filter 53 of the phase locked loop 43 of the second controllable signal conversion arrangement 32. The phase locked loop 43 is provided by the oscillator circuit 46 with an oscillator signal which is identical to the oscillator signal which is provided to the first phase locked loop 37. By coupling the second phase control current, there is a phase shift of the oscillator signal and this in turn has the consequence that the right-handed elliptical clock provided by the second controllable signal conversion arrangement 32 is elliptical, in particular The circularly polarized IF signal has a second phase shift.

The phase shift made by the first controllable signal conversion device 32 is the opposite of the phase shift that is performed by the second controllable signal conversion device 38. The first controllable signal conversion arrangement 32 effects a phase shift by a phase shift angle + F and the second controllable signal conversion arrangement 38 effects a phase shift by a phase shift angle -F.

The control of the Signalumsetzanordnungen 32 and 38 is carried out by means of a control unit 50, which is designed as a microprocessor 52 in the illustrated embodiment.

The microprocessor 52 supplies a first current supply element 54 with a first control signal which corresponds to a first phase shift angle given by the microprocessor and which causes the first current supply element 54 to apply the first phase control current to the first loop filter 47 of the phase locked loop 37 of the first controllable signal conversion device 32 to be coupled, wherein the coupling via a first phase control line 56 and the control input 39 of the first controllable Signalum- setzanordnung 32 takes place.

In a corresponding manner, the microprocessor 52 loads a second current supply element 58 with a second control signal which corresponds to a second phase shift angle specified by the microprocessor and which causes the second current supply element 58 to input a second one into the second loop filter 53 of the phase locked loop 43 of the second controllable signal conversion device 38 Coupling phase control current, wherein the coupling via a second phase control line 60 and the control input 45 of the second controllable Signalumsetzanordnung 38 takes place. As already mentioned, the second phase shift angle is not identical to the first phase shift angle. The second phase shift angle is preferably the same as the first phase shift angle.

The left-handed elliptical, in particular circularly polarized, intermediate-frequency signal provided by the first signal conversion arrangement 32 is supplied to a first input 64 of a second combination element 66 via a first controllable level adjuster 62. The right-handed elliptical, in particular circularly polarized, intermediate-frequency signal provided by the second controllable signal conversion arrangement 38 is supplied via a second controllable level controller 68 to a second input 70 of the second combination member 66. With the aid of the level adjusters 62 and 68, the levels of the intermediate frequency signals present at the inputs 64 and 70 are set to the same value. The second combiner 66 combines the intermediate frequency signals by adding the intermediate frequency signals. Since the intermediate frequency signals are mutually counter-elliptical, in particular circularly polarized, and since the amplitudes of the intermediate frequency signals present at the inputs 64 and 70 are the same, the combination of the intermediate frequency signals results in a linear output at a first output 72 of the second combining element 66 polarized output signal is applied.

The second combination element 66 can be designed, for example, as a directional coupler or as a 3 dB hybrid coupler.

By changing the phase shift angle F, the signal-to-noise ratio of the output signal can be maximized. The output signal, which is optimized by suitable selection of the phase shift angle F, corresponds to a linearly polarized satellite signal, which is transmitted in a polarization plane and received in a proportional manner by the two coupling probes 14 and 16. The output signal provided by the second combining element 66 has virtually no signal components from a second linearly polarized signal. satellite signal, which is transmitted in a plane oriented perpendicular to the first polarization plane second polarization plane.

If an output signal is to be provided which corresponds to the second linearly polarized satellite signal, then it is only necessary to increase the phase angle F by 90 °.

The change in the phase shift angle F taking place in order to optimize the output signal takes place by means of the microprocessor 52, which can be programmed for this purpose. For example, the microprocessor 52 can be given a starting value of the phase shift angle, which is then changed stepwise or continuously until the output signal has a maximum signal / noise ratio. Alternatively, it can be provided that the microprocessor calculates a start value of the phase shift angle, wherein the calculation can in particular incorporate the current location of the device 10, ie its GPS data, as well as the orbital position of the desired geostationary satellite.

At the first output 72 of the second combination member 66, a filter member 74 connects, which is configured in the illustrated embodiment as a bandpass 76. From the bandpass 76, the filtered output signal can be transmitted via a conventional coaxial cable 80 to a not shown in the drawing

Receiver are transmitted, for example, to a TV receiver.

From the receiver, not shown in the drawing, control signals can be transmitted to a first control signal input 82 of the microprocessor 52 via the coaxial cable 80, wherein the control signals can be coupled out of the coaxial cable 80 with the aid of a coupling-out element 84. The decoupling member 84 may be followed by a filter 86, so that the first control signal input 82, for example, a control signal with a frequency of 22 kHz can be provided. In particular, a control signal transmitted via the coaxial cable 80 to the microprocessor 52 may represent a measure of the signal-to-noise ratio of the output signal. The second combination element 66 has a second output 88, to which a power detector 90 is connected. The power detector 90 is in electrical communication with a second control signal input 94 of the microprocessor 52. The power detector 90 is provided by the second combination member 66 a signal to be measured, which corresponds to the output signal 72 applied to the first output. The power detector provides the microprocessor 52 with a measured value corresponding to the measured power. On the basis of this measured value, the two level adjusters 62 and 68 can be controlled by the microprocessor 52, with the aid of which the levels of the elliptically, in particular circularly polarized intermediate frequency signals can be changed so that identical to the inputs 64 and 70 of the second combination element 66 Level applied.

With the aid of the microprocessor 52, taking into account the measured value provided by the power detector 90, a control signal can also be provided to an amplifier control element 96, which causes the amplifier control element 96 to provide the controllable amplifiers 18 and 24 corresponding control signals, each with a certain degree of amplification correspond. This makes it possible to change the levels of the linearly polarized input signals. In addition, by alternately switching off the amplifiers 18, 24, functional tests can be carried out and unwanted phase errors can be detected.

A second advantageous embodiment of a device according to the invention for receiving linearly polarized satellite signals is shown schematically in FIG. 2 and is denoted overall by reference numeral 100.

The device 100 is configured substantially identically to the device 10 described above with reference to FIG. 1. For identical components, therefore, the same reference numerals are used in FIG. 2 as in FIG. 1, and with respect to these components, to avoid repetition referred to above. The device 100 differs from the device 10 in that the phase-locked loops 37 and 43 of the downconverters 33 and 40 are connected to a controllable DDS synthesis circuit 102 which provides the phase-locked loops 37, 43 with a phase control signal in the form of a reference clock signal. The reference clock signals are identical in their frequency, but they have a presettable phase difference (phase offset) in their phases. The DDS synthesis circuit 102 is controlled by the control unit 50, which sets the phase difference to the DDS synthesis circuit 102. The coupling of a phase control current into the phase locked loops 37, 43 is omitted in the device 100. Rather, the provision of the reference clock signals identical in their frequency but having a presettable phase difference in their phase ensures that the downconverters 33 and 40 are elliptical in opposite directions, in particular provide circularly polarized intermediate frequency signals, which differ in phase according to the predetermined phase difference of the reference clock signals.

Also in the device 100, the counter-elliptical, in particular circularly polarized intermediate-frequency signals, after they have passed through the controllable level adjusters 62 and 68, are combined with each other, so that the output 72 of the second combination element 66 is a linearly polarized output signal. By changing the phase shift angle of the two elliptically, in particular circularly polarized intermediate frequency signals, the signal / noise ratio of the output signal can be optimized. The change of the phase shift angle takes place by means of the DDS synthesis circuit 102 controlled by the control unit 50, which provides the phase locked loops 37 and 43 with phase control signals in the form of reference clock signals having a phase difference predetermined by the control unit 50.

The devices 10 and 100 make it possible to optimally receive a linearly polarized satellite signal in any polarization plane. gene, without the need for a mechanical adjustment of the devices 10 and 100 is required. The satellite signal is coupled into the waveguide 12 and each received to a certain proportion of the two Auskoppelsonden 14, 16 which are at an angle to each other, preferably aligned perpendicular to each other. The signal components correspond to the alignment of the output probes 14, 16 relative to the plane of polarization of the satellite signal. The input signals provided by the two coupling probes 14, 16, which are in each case linearly polarized, are converted into counter-rotating elliptical, in particular circularly polarized, high-frequency signals which are converted into counter-rotating elliptical, in particular circularly polarized, intermediate-frequency signals, while at the same time providing phase control signals. Signals a phase shift is made by specifiable phase shift angle. The elliptical, in particular circularly polarized intermediate frequency signals are finally combined to form a linearly polarized output signal. The signal-to-noise ratio of the output signal can be maximized by changing the phase shift angle. As already mentioned, the microprocessor 52 may be given a first phase shift angle, or a first phase shift angle may be calculated by the microprocessor 52, where in the calculation are the location coordinates (GPS coordinates) of the devices 10 and 100 and the orbit position of the desired geostationary satellite can flow into it. Subsequently, the phase shift angle of the microprocessor 52 can be changed stepwise or continuously until an optimum signal / noise ratio of the output signal is reached. The output signal then has a maximum amplitude and has practically only signal components of the desired linearly polarized satellite signal, but practically no signal components of an unwanted satellite signal. The devices 10 and 100 can thus be used to electronically correct the polarization error angle.

Claims

PATENT APPLICATIONS 1. A device for receiving linearly polarized satellite signals, comprising at least a first and a second coupling probe (14, 16), which are aligned at an angle to each other and project into a waveguide (12), wherein the first Auskoppelsonde (14) provides a first linearly polarized input signal and wherein the second Auskoppelson probe (16) provides a second linearly polarized input signal, and a signal processing device (13) for processing the two input signals, characterized in that the signal processing means (13) comprises a first combination element (22) which generates from the two linearly polarized input signals, a left-handed and a right-handed elliptically polarized high-frequency signal in that the signal processing device (13) has a controllable signal conversion arrangement (32, 38) for each of the two elliptically polarized high-frequency signals, wherein the high-frequency signals are converted into mutually opposite elliptically polarized intermediate frequencies by means of the two controllable signal conversion arrangements (32, 38) can be implemented, wherein the intermediate frequency signals relative to each other have a predetermined phase difference, and that the signal processing means (13) comprises a second combination member (66), by means of the second combination member (66), the two elliptically polarized intermediate frequency signals can be combined to form a linearly polarized output signal. 2. Apparatus according to claim 1, characterized in that by means of the first combination element (22) from the two linearly polarized input signals, a left-handed circularly polarized high-frequency signal and a right-handed circularly polarized high-frequency signal can be generated. 3. Device according to claim 1 or 2, characterized in that the signal processing device (13) has a control unit (50) for controlling the signal conversion arrangements (32, 38). 4. Apparatus according to claim 3, characterized in that the control unit (50) is designed as a microprocessor (52). 5. Device according to one of the preceding claims, character- ized in that the controllable Signalumsetzanordnungen (32, 38) as a down converter (33, 40) are configured, wherein at least one Signalumsetzanordnung (32, 38) has a phase locked loop (37, 43) , which can be acted upon by a phase control signal. 6. Apparatus according to claim 5, characterized in that the controllable Signalumsetzanordnungen (32, 38) are designed as integrated circuits. 7. Device according to claim 5 or 6, characterized in that the phase locked loop (37, 43) is connected to an oscillator circuit (46) which provides an oscillator signal to the phase locked loop (37, 43), and in that the phase locked loop ( 37, 43) has a loop filter (47, 53) which can be acted upon by a phase control current, wherein the phase control current represents the phase control signal. 8. Apparatus according to claim 5, 6 or 7, characterized in that the phase locked loop (37, 43) is associated with a controllable Stromeausbereitstellungs- member (54, 58) which the loop filter (47, 53) of the phase locked loop (37, 43) provides a phase control current. 9. Apparatus according to claim 8, characterized in that the power supply member (54, 58) is designed as a current pulse generator or digital-analog converter. 10. Apparatus according to claim 5 or 6, characterized in that the controllable Signalumsetzanordnungen (32, 38) each have a phase locked loop (37, 38), wherein the phase locked loops (37, 43) are connected to a controllable DDS synthesis circuit (102), which in each case provides to the phase-locked loops (37, 43) a phase control signal in the form of a reference clock signal, wherein the frequencies of the reference clock signals are identical and the phases of the reference clock signals are identical. clock signals have a predetermined phase difference to each other. 11. Device according to one of claims 5 to 10, characterized marked that the down converter (33, 40) each have a mixing member (35, 41), wherein by means of the mixing elements (35, 41) the frequency of the elliptically polarized high-frequency signals in an intermediate frequency can be implemented. 12. Device according to one of the preceding claims, character- ized in that the signal processing means (13) for each linearly polarized input signal has a controllable amplifier (18, 24). 13. The apparatus according to claim 12, characterized in that the  controllable amplifiers (18, 24) are connected to an amplifier control member (96). 14. The apparatus of claim 13, characterized in that the amplifier control member (96) by a control unit (50), a control signal is provided. 15. Device according to one of the preceding claims, character- ized in that the signal processing device (13) for each intermediate frequency signal has a controllable level control (62, 68) has up. 16. The apparatus according to claim 15, characterized in that the level controllers (62, 68) by a control unit (50) in each case a control signal is provided. 17. Device according to one of the preceding claims, characterized in that the levels of the intermediate frequency signals are adjustable to identical values. 18. Device according to one of the preceding claims, character- ized in that the second combination member (66) is arranged downstream of a filter member (74). 19. The device according to claim 18, characterized in that the filter member (74) is designed as a bandpass (76). 20. Device according to one of the preceding claims, characterized in that the signal processing device (13) comprises a power detector (90), which can be acted upon by the second combination element (66) with a signal to be measured, the output signal of second combination element (66), wherein the power detector (90) of a control unit (50) provides a measured value corresponding to the measured power.