JPH0142173B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to correction of polarization errors in artificial satellites, and particularly to a method for correcting interference polarization errors of orthogonally polarized antenna systems in artificial satellites.

[Background of the invention]

A new satellite communication system is being planned to broadcast video, audio, data communication, etc. to each home at relatively high power (EIRP 50 dBW or more). This communication method is called direct broadcast satellite (hereinafter referred to as DBS) communication, and its downlink frequency is in the 12GHz frequency band (approximately 12.2~12.7GHz), and the feeder link (uplink) frequency is in the 17GHz frequency band (approximately 17.3~12.7GHz).
17.8GHz).

In the 17.3~17.8GHz band DBS feeder link,
It is necessary to extremely improve both the separation between every other channel having a common plane of polarization by frequency and the separation between partially overlapping and orthogonal adjacent channels by antenna polarization discrimination. Federal Communications Commission Report and Orders of March 1983, Combined Docket No. 80.
According to No. 348, the recommended spacing between channels with a common plane of polarization is 26 MHz, and that between adjacent orthogonal channels is 13 MHz. Since the maximum bandwidth required for each channel is 24 MHz, there is a 2 MHz guard band between common polarization channels. The center frequency of each channel is the center of a 2 MHz wide guard band for adjacent orthogonally polarized channels.

During precipitation, interferometric polarization discrimination is better for linearly polarized waves than for circularly polarized waves, and when the orthogonal axis of radiation of linearly polarized waves coincides with the local horizontal and vertical axes, the advantage of interferometric polarization discrimination over interferential polarized waves is greatest. (``Nasa Technical Report 1770'')
February 1982 Issue No. 35-45, “Canadian CPM Contribution
B8”, May 1982 issue).

from a typical coverage area (e.g. US time zone) to a constellation of geostationary orbit satellites communicating into that area.
In DBS feeder link communications, the direction of linearly polarized radiation leaving each part of the coverage area along the local vertical axis varies by about 20 degrees when received by the satellite. Two adjacent and partially overlapping signals are not perfectly orthogonal to the desired signal because they emanate from a different location than the desired signal and tend to produce interfering signals. The satellite itself also does not maintain a constant orientation and may rotate about its yaw axis, which is generally close to the boresight axis of its antenna. Due to this rotation of the polarization plane of the antenna, the former will cause interference with the latter, regardless of whether the partially overlapping uplink signal and the desired signal are perpendicular to each other or not.

[Summary of the invention]

In accordance with one embodiment of the invention, a first antenna element of a first orientation of polarization received by a first antenna element oriented to receive a first orientation of polarization.
A method and apparatus are described for compensating for cross-coupling of a second, oppositely polarized signal of a channel in an adjacent and overlapping frequency band to a signal in a channel of said channel. The method includes sensing the adjacent channel signal by a second antenna element adapted to receive the second opposite polarization, and sensing the adjacent channel signal of the second opposite polarization at the first antenna element. senses the cross-coupling percentage of the signal of the second antenna element, reduces the amplitude of the adjacent channel signal sensed by the second antenna element to the level of the cross-coupling percentage, and transmits the reduced amplitude signal of the adjacent channel to the first antenna element.
and the first channel signal from the antenna element.

[Detailed explanation]

A detailed description will be given below with reference to the accompanying drawings.

In FIG. 1, three feeder link ground stations A, B,
C is shown. Satellite S has the same coverage area with other satellites configured to receive every other (next) common polarization channel and/or neighboring channels with crossed polarization in an overlapping relationship. They form close groups.

The feeder link ground station is e.g. 17.3~17.8GHz
The spacing between common polarization feeder link channels is, for example, 26 MHz. Since the bandwidth of each channel is 24MHz, there is a guard band of 2MHz. In this example, a horizontally polarized feeder link channel is centered 13 MHz offset from a corresponding vertically polarized adjacent feeder link channel. For example, ground station B emits the required vertically polarized signal E _WV on channel WV, and ground station A transmits the horizontally polarized signal of the lower neighbor on channel LH, which overlaps with the vertically polarized signal E WV.
Consider the case where the ground _station C emits a corresponding horizontally polarized signal of the upper neighbor on an overlapping channel UH. FIG. 2 shows the frequency assignment for each polarization. For example, here we have a horizontal polarization channel LH of center frequency f _L from station A, and then a horizontal polarization channel LH of center frequency f L from station A, and then
There is a horizontal polarization channel UH with said common plane of polarization from station C with f _U , and between this horizontal polarization channel LH and UH there is a 2 MHz guard band with a center frequency f _W . Each vertically polarized channel is biased such that its center frequency lies in the center of the guard band between each horizontally polarized channel represented by the center frequency f _W of the desired frequency channel WV, which extends between frequencies f _W1 and f _W2 . are doing. This feeder link frequency band is, for example, 24 MHz in the 17.3-17.8 GHz frequency band for direct broadcast satellite communications. Focusing on the desired signal E _WV of the desired vertical polarization channel WV, the interference signal is, for example, the interfering horizontal polarization signal E _LH of the lower neighbor from station A.
and the corresponding horizontally polarized signal from station C
E _UH . The satellite feeder link receiving antenna 10 typically comprises a linear feed oriented parallel to (coplanar with) the desired transmitted signal E _WV .

A ground station such as station B is a satellite receiving antenna 10.
is on the boresight axis AX. This antenna 10
is oriented such that its receive antenna polarization direction for receiving the desired signal E _WV is coplanar with the direction of local vertical polarization of the antenna of ground station B. The signal received in the polarization direction of this satellite's receiving antenna is expressed as E _C. Satellite antenna boresight axis
The local horizontal linear deflection signals E _LH , E _UH from the ground stations off AX are out of perpendicularity with the signal E _WV when received by the satellite's antenna 10 . The signal from station A to the southwest of the local vertical plane passing through ground station B and satellite S is rotated counterclockwise as seen from the satellite, and the signal from ground station C to the southwest is rotated clockwise. The direction of polarization of the signal E _WV at the spacecraft may change by 20 degrees or more as the feeder link ground station moves from one end of the coverage area E to the other.

During precipitation, the horizontal polarization component of the linearly polarized transmitted signal in any direction is attenuated more strongly than the vertical polarization component, so the polarization of the signal received by the satellite is localized to the local vertical polarization defined by the location of the feeder link station. rotating in the direction. The advantage of this local vertical polarization is that polarization rotation does not occur during precipitation. The same advantage exists for local horizontal polarization, but the latter signal is more attenuated than the former.

This rotation of the polarization of the received signal during precipitation induces significant cross-coupling of the signal between the horizontal and vertical channels. Also, because the satellite may rotate about its antenna's boresight axis and/or yaw axis Y, this apparent polarization rotation causes significant cross-coupling of the signals.

One feature of this device is that, for example, the vertical linear polarization feed at ground station B coincides with the vertical feed axis along the local vertical plane at that station B, so that the E _WV
The signal is transmitted with a polarization angle represented by the vector _WV . The ground station B is located at the center of the effective range E of the satellite S. If the satellite's orientation error in the yaw axis is zero, the polarization angles of the received signal, represented by vector _C , are coplanar with vector _WV , and the polarization angles θ _W of each of those angles as seen from the satellite are It is 0.
A second linearly polarized feed ground station can also be provided at ground station B oriented along the polarization _WH orthogonal to E _WV (see Figure 3). This second linear feed may also feed other antennas of the satellite S or of a satellite in the same constellation as the satellite S. In Figure 3, _WH represents the polarization of the signal perpendicular to the desired signal E _WV of polarization _WV , and θ _L and θ _U respectively
represents each polarization angle (as seen from the satellite) for the signal E _LH of polarization _LH from station C and the signal E _WH of polarization E _UH from _station C. Signal E _X is a satellite signal perpendicular to E _C and has a polarization angle represented by vector _X. For a US time zone coverage, B _L , θ _U may vary between approximately -10° and +10° on either side of a local vertical plane defined at the center of the coverage E.

The device described here performs an electronic rotation of the effective plane of polarization of the satellite feeder link receiving antenna, so that this results in frequency channels LH,
It becomes perpendicular to both the useless signals E _LH and E _UH of UH and no longer responds. Signals from stations A and C E _LH , E _UH
are from the opposite side of the local vertical plane at station B, so they are not coplanar. Therefore, this rotation correction must be performed separately for each signal that is likely to interfere. From Figure 3, the signals E _C and E _X at the satellite are expressed by the following equations.

E _C = E _WV cosθ _W +E _LH sin (θ _W +θ _L ) +E _UH sin (θ _W +θ _U ) (1a) E _X = −E _WV sinθ _W +E _LH cos (θ _W +θ _L ) +E _UH cos (θ _W + θ _U ) (1b) When these signals pass through a narrow band filter that only passes f _L < f < f _W , the signals in the final terms of equations (1a) and (1b)
The half-channel common to E _WV and E _LH can be erased. Subtracting the part _{α of} signal _E
E _WV is obtained.

_{E C −αE _ _ _ _ _ _ _} To eliminate the coefficient of E _LH , α=sin(θ _W +θ _L )/cos(θ _W +θ _L ) = tan(θ _W +θ _L ) Therefore, E _C −E _X tan(θ _W +θ _L ) = E _WV {cos θ _W + sin θ _W tan (θ _W + θ _L )} (3) When this theory is converted into hardware, the task is to find the coefficient α in equation (2). This is equation (1a),
The purpose is to find the value of tan (θ _W + θ _L ), which is the ratio of the second term on the right-hand side of ( _1b ). This is done by filtering E _C and _E This is done after filtering. Since there is no precipitation depolarization of linearly polarized radiation along the local vertical or horizontal plane, the coefficient α
is a real number (not a complex number), and positive (when θ _L is positive) is negative. The gain of _the E _X channel then decreases by _{a factor of} α (with respect to _E (determined by bandpass filter)
E _WV that does not contain E _LH is obtained.

Next, FIG. 4 shows a receiving feeder link satellite antenna device 10 according to one embodiment.
The satellite feeder link antenna system 10 includes a vertical polarization dominant pickup element or horn 11 and a horizontal polarization dominant pickup element or horn 13. The vertical polarization dominant signal E _C received by the horn 11 is amplified by an amplifier 15 , and a signal with a frequency between f _U and f _L is applied to an amplifier 33 through a bandpass filter 31 . The output signal of amplifier 15 is also
The signal is applied to the first ratio detector 17 via a narrow band filter 16 that passes a frequency of f _L ±several 100 KHz (for example, 300 KHz). This feeder link signal is FM modulated into a carrier wave. The signal picked up by the horizontal polarization dominant horn element 13 is amplified by an amplifier 19, and a signal with a frequency of f _L ±several 100 KHz is applied to a ratio detector 22 through a narrow band filter 21. Further, signals of frequencies f _L to f _W are applied to an amplifier 30 through a bandpass filter 29 .

The baseband signal detected by the ratio detector 17 (baseband video signal in the case of television broadcasting) is divided by the baseband signal detected by the detector 22 by the divider 37 to α in equation (2). Generate a proportional ratio signal. This division is done by detector 1
a logarithmic amplifier for amplifying the sensed baseband signal of each output of 7 and 22, a differential amplifier for differentially summing the two logarithmic signals, and an anti-logarithm device coupled to the differential amplifier. This can also be done using the divider 37. The antilogarithm device can be a feedback amplifier with a logarithmic amplifier in the feedback path. The output of the divider 37 (in the above example, the output of the antilogarithm device) is therefore equal to the value α of tan(θ _W +θ _L ). The detected horizontal polarization dominant signal f _L ~ from element 13
The f _W signal passes through the f _L -f _W bandpass filter 29 and is amplified by the amplifier 30 . This RF signal is transmitted to the divider 37
The signal is applied to an AGC amplifier 41 having a gain determined by the ratio signal of the output. Therefore the signal from horn 13
The gain of E _X is (with respect to the signal E _C from horn 11)
It decreases with α as a coefficient. _{The result αF}
A signal equal to the desired vertically polarized signal E _WV without the interfering polarized signal E _LH is generated between f _W . This algebraic subtraction can also be performed by inverting the signal from the amplifier 41 with an inverter 43 before being applied to the summing means 35, which may also be a summing waveguide.
The signals summed by means 35 are then filtered through the appropriate satellite transceiver 44 for that channel;
It is converted to a downlink frequency and launched towards the Earth's effective range E.

Coefficient β = tan in the range of several 100 KHz centered on f _U
By finding (θ _W + θ _U ) using the same theory and method,
E _WV without E _UE is obtained between f _W and f _V.

In FIG. 4, the output of the amplifier 15 is applied to a narrow band filter 46, and the output of the amplifier 15 is applied to a _narrow band filter 46, and
A narrow band upper half common frequency signal of 300KHz) is applied to the detector 53. This signal is detected by the ratio detector 53
The signal is detected and applied to the divider 57. amplifier 1
The output of 9 is also applied to a narrowband filter 51 of f _U and a bandpass filter 49 of f _W to f _V . A narrowband signal centered at f _U is detected by a detector 50 and applied to a divider 57 . The output signal of the divider representing the ratio of these narrowband signals centered on f _U and the coefficient β are applied to the AGC amplifier 55 . The f _W - f _U band signal is amplified by the amplifier 47 and applied to the AGC amplifier 55,
Here, the gain of the signal in the f _W to f _U band (E _X ) is reduced using β as a coefficient. The resulting output _βEX of the amplifier 55 passes through the inverter 43a and is algebraically subtracted from the detection signal E _C by the adding means 35.

The amplitudes of the lower and upper halves of the obtained E _WV channel differ as follows.

_{When f L ≦ f ≦ f W , E C −E _ , E C −E _ _ _ _ _} If this small relative amplitude correction needs to be made to prevent distortion of the signal E _WV , this can be done by calculating this ratio from the measured values of θ _L , θ _U , and θ _W (which can be measured at f _W ). This can be achieved by One way to keep the amplitudes of the upper and lower halves equal is to
Compare the division ratios of the two dividers as shown in the figure,
The ratio of the smaller divider of the fraction to both AGC amplifiers 4
It is applied as a gain of 1.55.

There are several alternative techniques, but they have advantages and disadvantages. One recommended method is to orient all linearly polarized feeder link ground station transmitting antennas so that they are coplanar or orthogonally polarized with respect to the signal from the center of coverage as seen from the DBS satellite constellation. It is something to do. For example, by rotating the locally vertically and horizontally polarized antenna of ground station A in Figure 1 slightly clockwise around the straight line connecting satellites S and A, antenna to satellite S and C
Rotate counterclockwise around the straight line connecting . Since ground station B is on the boresight axis of the satellite's antenna, the local vertical plane is defined at B and no correction is required. This method has the advantage that both θ _L and θ _U are 0, and equation (3) becomes as follows.

_{E C −E _ _} ^_ _{_ _ _ _ _ _ _} and the invention may be used only to compensate for changes in θ _W as the satellite rotates about the yaw axis Y (generally along the direction of propagation from the satellite's antenna to the center of coverage). Another disadvantage is that the polarization near the edge of the effective range deviates by as much as 10° from the local vertical plane.

The recommended scheme, which operates when all ground station antennas are coplanar or orthogonally polarized as viewed from the DBS satellite, is shown in Figure 5. The dominant vertically polarized signal of E _C is picked up by antenna element 110 and is transmitted to amplifier 115.
is amplified. This amplified signal is passed through a bandpass filter 131
The required signals in the passband f _W1 to f _W2 are applied to the amplifier 133 through this. The signal of the dominant horizontal antenna element 113 is amplified by an amplifier 119 and applied to a filter 129, which has the same passband.
Only the required signals from f _W1 to f _W2 pass through this to amplifier 1.
22. The low frequency f _L and high frequency f _U of amplifiers 115 and 119 are connected to two narrow band filters 1
16 and 121, and is detected by detectors 117 and 123. The baseband signal from detector 117 is divided by the baseband signal from detector 123 in divider 137 to generate a fractional gain signal that is applied to AGC amplifier 141 . Amplifier 14
The attenuated output of 1 is inverted by inverter 143 and added to the output signal from amplifier 133 to compensate for variations in θ _W as the satellite rotates about its yaw axis.

Another alternative technique is to use a pilot carrier to derive (θ _W +θ _L ), (θ _W +θ _U ), and/or θ _W . The advantage of this is that the signal from which the phase angle is derived is more constant; the disadvantage is that the pilot carrier adds to the complexity of the feeder link hardware. This pilot carrier may even be at a band edge telemetry, tracking and control frequency, where it is also used for satellite orientation reference and/or range estimation.

The invention can also be used in advanced XPD for circular polarization. In this case, α becomes a complex ratio, but
There is no need to compensate for slow rotation around the yaw axis. When there is precipitation, the horizontally polarized component of the transmitted signal also experiences a larger phase lag than the vertically polarized component.
This amount of phase delay depends not only on the amount of precipitation but also on the operating frequency. It is desirable to correct this phase difference in the uplink frequency of the 17 GHz band mentioned above. The higher the operating frequency, the greater the need to correct for this delay. In one embodiment of this invention,
To correct this phase difference, the difference in delay between frequencies in the guard band is detected. In the embodiment shown in _FIG .
(see FIG. 6), and the detected phase difference signal obtained from the output of the phase comparator 42 is supplied to a phase shifter to adjust the phase of both signals added by the adding means 35. One way to do this, as shown in FIG. 6, is to replace the inverter 43 in FIG.
The purpose is to use a variable phase shifter that provides a phase shift of 180° minus an amount corresponding to the detected phase difference. For example, horizontal pick-up element 1 in FIG.
The f _L signal picked up in step 3 is compared to the f _L signal picked up in vertical pick up element 11.
If the comparator 42 (FIG. 6) detects that the phase is delayed by 20 degrees, the amount of phase shift in the phase shifter 43 is adjusted to 160 degrees (180 degrees - 20 degrees). Another method is
In FIG. 4, the signal from the vertical pickup element 11 is delayed by the amplifier 33 by the detected phase difference to equalize the phases of both signals in the adding means 35. In the case of the embodiment shown in FIG. 5, the inverter 143 is a phase shifter, and the detectors 117 and 1
The phase of the signal obtained from 23 is determined by the phase comparator 143.
a, and the obtained signal is sent to the phase shifter 143 described above.
is supplied to adjust the amount of phase shift.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a satellite and a predetermined coverage area with a feeder link ground station, Figure 2 is a diagram showing frequency allocation for a satellite feeder link frequency reuse scheme using orthogonal linear polarization, and Figure 3 is a diagram of a satellite. FIG. 2 is a vector diagram showing various polarization angles of the feeder link signal as seen from FIG. FIG. 4 is a diagram showing a device for equalizing the amplitudes of the upper and lower sidebands of the device; FIG. 5 is a block diagram of a device for compensating for interference polarization according to the second preferred embodiment of the present invention; FIG. 6 is a diagram showing the phase 5 is a block diagram illustrating a modification of the apparatus of FIG. 4 for correcting delays; FIG. S...Artificial satellite, 10...Receiving feeder link satellite antenna device, 11,110...Vertical polarization dominant pick-up element constituting first antenna pick-up means, 13,113...Horizontal polarization dominant pick-up element constituting second antenna pick-up means polarization dominant pickup elements, 37, 137... dividers constituting means for sensing the ratio of the second polarization signal, 41, 141...
an AGC amplifier constituting means for reducing the amplitude of the second channel signal in proportion to the ratio of the second polarization signal;
35, 135... Adding means constituting means for differentially adding, 42... Phase comparator, 43... Phase shifter.

Claims (1)

[Claims] 1. A first channel signal having a first polarization direction received by the first antenna pickup means and a second channel signal having a second polarization direction opposite thereto. a channel of signals in a predetermined channel or frequency band separated by a guard band, the channel of the first polarization being frequency-biased from the channel of the second polarization; A first polarized wave having the above-mentioned first polarized wave direction in frequency reuse by a polarization diversity method in which the center frequency of each channel of polarized wave is located in a guard band between each channel of the first polarized wave. A method for compensating for cross-coupling interference of a second channel signal having a second polarization direction opposite to the cross-coupling interference of a second channel signal, the method comprising: receiving a polarization signal having the opposite second polarization direction; sensing a second channel signal by a second antenna pickup means adapted to pick up a second channel; and protection adjacent to said first channel received by said second and first antenna pickup means. sensing a ratio of amplitudes of second polarized signals of band frequencies; reducing the amplitude of the second channel signal sensed by the second antenna pickup means in proportion to the ratio; differentially adding the reduced second channel signal with the first channel signal received by the first antenna pickup means; sensing a delay difference between second polarization signals of guard band frequencies adjacent to the first channel received by the pick-up means; The relative phase of the second channel signal received by the second antenna pickup means with respect to the phase of the second channel signal received by the antenna pickup means is determined at the guard band frequency. A method for compensating for polarization errors comprising adjusting in response to a sensed delay difference. 2. A first channel signal having a first polarization direction received by the first antenna pickup means and a second channel signal having a second polarization direction opposite thereto are protected. in predetermined channels or frequency bands separated by bands, wherein said channel of said first polarization is frequency-biased from said channel of said second polarization, and said channel of said first polarization is frequency-biased from said channel of said second polarization; of the first channel signal having the first polarization direction in frequency reuse by a polarization diversity method, the center frequency of which is located in the guard band between each channel of the first polarization; A method for compensating for cross-coupling interference caused by a signal of a second channel having an opposite second polarization direction, the method comprising receiving polarization in the second opposite direction. sensing a second channel signal by a second antenna pickup means; and sensing a second channel signal of a guard band frequency adjacent to the first channel received by the second and first antenna pickup means. sensing a ratio of the amplitudes of the polarized signals; reducing the amplitude of the second channel signal sensed by the second antenna pickup means in proportion to the ratio; and differentially adding the signals of the first channel received by the first antenna pickup means, and the signals of the first channel received by the second and first antenna pickup means. sensing a delay difference between second polarized signals of guard band frequencies adjacent to the first channel, wherein the differentially summing step is performed by the first antenna pickup means; The relative phase of the second channel signal received by the second antenna pickup means with respect to the phase of the received second channel signal is determined by the difference in the sensed delay at the guard band frequency. adjusting the second channel according to the phase of the second channel signal received by the first antenna pickup means.
adjusting the relative phase of said second channel signal received by said antenna pickup means by an amount equal to 180° minus a difference in the sensed delay at said guard band frequency. , a method to compensate for polarization errors. 3. A first channel signal having a first polarization direction received by the first antenna pickup means and a second channel signal having a second polarization direction opposite thereto are protected. in predetermined channels or frequency bands separated by bands, wherein said channel of said first polarization is frequency-biased from said channel of said second polarization, and said channel of said first polarization is frequency-biased from said channel of said second polarization; of the first channel signal having the first polarization direction in frequency reuse by a polarization diversity method, the center frequency of which is located in the guard band between each channel of the first polarization; A device for compensating for cross-coupling interference caused by a signal of a second channel having an opposite second polarization direction, the device being configured to receive polarization in the opposite second direction. a second antenna pickup means, means for sensing a second channel signal; and a second antenna pickup means coupled to said first and second antenna pickup means for receiving said second channel signal. means for generating a gain control signal proportional to a ratio of a second channel signal of a guard band frequency adjacent to the first channel; means for sensing the second channel signal; and means for generating the gain control signal. means coupled to the second antenna pickup means for reducing the amplitude of the second channel signal sensed by the second antenna pickup means in proportion to the ratio; means for differentially adding the first channel signal received by the antenna pickup means of the second channel;
and means for sensing a delay difference between second polarized signals of guard band frequencies adjacent to the first channel received by the first antenna pickup means, and the differentially summing means as described above. is the relative phase of the second channel signal received by the second antenna pickup means with respect to the phase of the second channel signal received by the first antenna pickup means. , means for adjusting in response to a sensed difference in delay at said guard band frequency. 4. A first channel signal having a first polarization direction received by the first antenna pickup means and a second channel signal having a second polarization direction opposite thereto are protected. in predetermined channels or frequency bands separated by bands, wherein said channel of said first polarization is frequency-biased from said channel of said second polarization, and said channel of said first polarization is frequency-biased from said channel of said second polarization; of the first channel signal having the first polarization direction in frequency reuse by a polarization diversity method, the center frequency of which is located in the guard band between each channel of the first polarization; A device for compensating for cross-coupling interference caused by a signal of a second channel having an opposite second polarization direction, the device being configured to receive polarization in the opposite second direction. a second antenna pickup means, means for sensing a second channel signal; and a second antenna pickup means coupled to said first and second antenna pickup means for receiving said second channel signal. means for generating a gain control signal proportional to a ratio of a second channel signal of a guard band frequency adjacent to the first channel; means for sensing the second channel signal; and means for generating the gain control signal. means coupled to the second antenna pickup means for reducing the amplitude of the second channel signal sensed by the second antenna pickup means in proportion to the ratio; means for differentially adding the first channel signal received by the antenna pickup means of the second channel;
and means for sensing a delay difference between second polarized signals of guard band frequencies adjacent to the first channel received by the first antenna pickup means, and the differentially summing means as described above. is the relative phase of the second channel signal received by the second antenna pickup means with respect to the phase of the second channel signal received by the first antenna pickup means. , means for adjusting in response to a sensed difference in delay at said guard band frequency; and means for adjusting the relative phase of said second channel signal received by said first antenna pickup means. The delay difference sensing means senses the relative phase of the second channel signal received by the second antenna pickup means with respect to the phase of the second channel signal received from 180°. An apparatus for compensating polarization errors, comprising means for adjusting by an amount equal to a value minus a delay amount. 5. A first channel signal having a first polarization direction received by a first antenna pickup means provided on a satellite, and a second channel signal having a second polarization direction opposite thereto. is in a predetermined channel or frequency band separated by a guard band, and the channel of the first polarization is frequency-biased from the channel of the second polarization to produce a second polarization. A first channel having the direction of the first polarized wave in frequency reuse by a polarization diversity feeder link method, wherein the center frequency of each channel is located in the protection band of the first polarized wave. A device for compensating cross-coupling interference of a signal of a second channel having a second polarization direction opposite to the cross-coupling interference of a signal of a second antenna pickup means coupled to said first and second antenna pickup means, said means for sensing a second channel signal;
The second channel of the guard band frequency adjacent to the first channel received by the antenna pickup means of
means for generating a gain control signal proportional to the ratio of the signals of the channels; coupled to means for sensing the second channel signal; and means for generating the gain control signal; means for reducing the amplitude of the second channel signal received by the first antenna pickup means in proportion to the ratio; and the second channel signal having the reduced amplitude received by the first antenna pickup means. means for differentially summing the signal of the second channel, and sensing a delay difference between a second polarized signal of a guard band frequency adjacent to the first channel received by the second and first antenna pickup means. and means for differentially summing the phase of the second channel signal received by the first antenna pickup means. Apparatus for compensating polarization errors, characterized in that it comprises means for adjusting the relative phase of the received second channel signal in response to a sensed difference in delay at the guard band frequency. . 6. A first channel signal having a first polarization direction received by a first antenna pickup means provided on a satellite, and a second channel signal having a second polarization direction opposite thereto. is in a predetermined channel or frequency band separated by a guard band, and the channel of the first polarization is frequency-biased from the channel of the second polarization to produce a second polarization. A first channel having the direction of the first polarized wave in frequency reuse by a polarization diversity feeder link method, wherein the center frequency of each channel is located in the protection band of the first polarized wave. A device for compensating cross-coupling interference of a signal of a second channel having a second polarization direction opposite to the cross-coupling interference of a signal of a second antenna pickup means coupled to said first and second antenna pickup means, said means for sensing a second channel signal;
The second channel of the guard band frequency adjacent to the first channel received by the antenna pickup means of
means for generating a gain control signal proportional to the ratio of the signals of the channels; coupled to means for sensing the second channel signal; and means for generating the gain control signal; means for reducing the amplitude of the second channel signal received by the first antenna pickup means in proportion to the ratio; and the second channel signal having the reduced amplitude received by the first antenna pickup means. means for differentially summing the signal of the second channel, and sensing a delay difference between a second polarized signal of a guard band frequency adjacent to the first channel received by the second and first antenna pickup means. and means for differentially summing the phase of the second channel signal received by the first antenna pickup means. means for adjusting the relative phase of the received second channel signal in response to a sensed delay difference at the guard band frequency; Means adjusts the relative phase of the second channel signal received by the second antenna pickup means to the phase of the second channel signal received by the first antenna pickup means by 180°. Apparatus for compensating for polarization errors, characterized in that it comprises means for adjusting by an amount equal to the sensed delay amount subtracted by the means for sensing the difference in delay from .