JPS6025339A - Circuit for eliminating interference of cross polarized wave - Google Patents

Abstract

PURPOSE:To correct simply the amount of phase rotation of each delay circuit of a transversal filter by controlling and adjusting a complex phase angle of a tap coefficient corresponding to a specific tap in each tap of the transversal filter. CONSTITUTION:The circuit consists of a transversal filter 7 at a horizontal polarized wave channel, a phase adjusting means 10, a synthesis circuit 12, a transversal filter 8 in a vertical polarized wave channel, a phase adjusting means 11, a synthesis circuit 13, and a control signal generating means 9 formed by a horizontal polarized wave control signal generating means 9-1 and a vertical polarized wave control signal generating means 9-2. A demodulating means 14 is connected to the synthesis circuits 12 and 13. The complex phase angle of the tap coefficient corresponding to the specific tap among 2-N sets of other taps in the transversal filter is controlled and adjusted by referencing the phase of an intermediate frequency modulating signal in the 2N sets of other taps based on the phase of the intermediate frequency modulating signal of a main tap as a reference.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cross-polarization interference cancellation circuit, and more particularly to an improvement of the transversal filter in a cross-polarization interference cancellation circuit including a transversal filter.

In wireless communication systems in the microwave band, in order to increase transmission capacity, a method is often used in which two orthogonal polarized waves are used to simultaneously propagate in free space. However, in the free space forming the spatial transmission line, anisotropy due to a medium such as rain intervenes,
Interference signals occur due to the generation of cross-polarized waves between the two orthogonal polarized waves, which poses a problem in maintaining the quality of communication lines.

In order to remove interference signals due to such cross polarization,
On the receiving side, a cross-polarization interference removal circuit is provided.
However, in recent years, with the practical use of digital wireless transmission systems in the microwave band, the cross-polarization interference removal circuit has also taken advantage of the features of digital wireless transmission systems, such as applying transversal filters. In addition, a more efficient method has been put into practical use. An overview of a conventional cross-polarization interference cancellation circuit applied to this digital wireless transmission system will be explained in order to clarify its problems.

FIG. 1 is a block diagram showing the main concept of a conventional example of the cross-polarization interference cancellation circuit. As shown in Figure 1,
This conventional example includes a pair of transversal filters 1 and 2, horizontal polarization control signal generating means 3-1 and vertical polarization control corresponding to the transversal filters of each channel of horizontal polarization and vertical polarization, respectively. Signal generation means 3
-2, a horizontal polarization channel combining circuit 4, and a vertical polarization channel combining circuit 5. Horizontally polarized and vertically polarized intermediate frequency modulated signals S and S input from terminals 101 and 102, respectively, are input to transversal filters A and 2, respectively. In the transversal filter, the transversal signal sent from the control signal generating means 3-1 is
In-phase control signals for horizontal polarization (yH, ---, yH9-N 0 --*YHrYH) and quadrature control signals (dH9N-) corresponding to each tap of the filter
I N -N ---, dH, -1-dH, d), the above change 0
'N-IN Modulation signal S The modulation signal generated at each tap is given a predetermined weighting, added according to a predetermined procedure, orthogonally combined, and output as a modulation signal S, which is vertically polarized. The signal is input to the channel combining circuit 5. At the same time, the modulated signal at the main tap of the transversal filter 1 is output as a modulated signal S without being weighted, and is input to the horizontal polarization channel combining circuit 4. Through a similar operation procedure, the transversal filter 2 also generates the in-phase control signal for vertical polarization (r l -""" u r l -1-1, rN-□
,.

-N 0 rN) and orthogonal control signal (d-N l ---1d□
++ −−−−1−11dN−□−+dN),
Modulated signal S which is the output of transversal filter 2
B and the modulating signal S at the main tap. and are input to a combining circuit 4 for the horizontal polarization channel and a combining circuit 5 for the vertical polarization channel, respectively. The output signals sH and sV of the combining circuits 4 and 5 are CC input into the modulation means 6, and predetermined demodulated signals S and SD are respectively generated and outputted via terminals 103 and 104. Specific signals SF and SB for each channel of horizontal polarization and vertical polarization, including error signals for each demodulation signal and cross-polarization interference removal, are generated, and are transmitted to vertical polarization control signal generating means 3-2 and SB, respectively. The signal is sent to the horizontal polarization control signal generating means 3-1. In the control signal generating means 3, the specific signals S and SF are inputted,
In-phase control signals and quadrature control signals for each of the horizontally polarized and vertically polarized channels described above are generated and input to transversal filters 1 and 2, respectively, to form a system of cross-polarized interference removal circuits. .

FIG. 3 shows the main components of the above-mentioned conventional cross-polarization interference cancellation circuit, excluding the control signal generating means 3 in FIG. 1. When there are two delay circuits constituting the conventional transversal filter, this corresponds to the case where N=1. In FIG. 3, a horizontally polarized modulated signal is input from the terminal 109 in the horizontally polarized channel, and the modulated signal of each tap corresponding to each terminal of the delay circuits 15 and 16 is transmitted to the cable 17 on the in-phase side. -1.18-1 and 19-1, variable weighting circuits 20-1.21-1 and 22-
1, and on the orthogonal side, each cable 1
The variable weighting is output via 7-2.18=2 and 19-2 to circuits 20-2.21-2 and 22-2. Variable weighting on the in-phase side is provided by circuit 20-1.

Terminal 11 for 21-1 and 22-1, respectively.
0.112 and 114, the in-phase control signal r sent from the above-mentioned horizontal polarization control signal generation means 3-1.
, r and r are respectively inputted, and the variable weighting on the orthogonal side is performed by the circuit 20-2゜2.
1-2 and 22-2, respectively, terminal 111
．． The orthogonal control signal d, which is also sent from the horizontal polarization control signal generation means 3-1 via 113 and 115,
d and d are each powered by -10 people. The modulated signals at each of the taps are weighted by the in-phase control signal and the orthogonal control signal, and then added in the adder circuit 23-1 on the in-phase side and inputted to the orthogonal control signal 24, and on the orthogonal side, the modulated signal is added in the adder circuit 23-1. The signals are added at 23-2 and input to the orthogonal coupling circuit 24. In the orthogonal coupling circuit 24, these added modulation signals are coupled with each other in a phase relationship of 77 cyan, and the output thereof is sent to the vertical polarization channel synthesis circuit 3.
Sent to 6. On the other hand, the modulated signal at the main tap is outputted from 11 and inputted to the horizontal polarization channel combining circuit 25.

Similarly, on the vertical polarization channel side, terminal 1
A vertically polarized modulation signal is input from terminal 17, and an in-phase control signal r-
□1ro and r□ are input, and further terminals 119 and 12
1 and 123, orthogonal control signals d, , do, and are input to the cable 28-1 on the in-phase side through the same operation process as in the case of the horizontal polarization channel described above.
．． 29-1 and 30-1, and the variable weighting circuit 31-
1.32-1 and 33-1, the modulation signal weighted corresponding to each tap is sent to the adder circuit 3.
Cables 28-2, 29-2 and 30-
2, and variable weighting circuits 31-2, 32-2 and 33
-1, the modulated signals weighted corresponding to each tap are added in the adder circuit 34-2 and output. These addition outputs are sent to the orthogonal coupling circuit 35
After being combined with each other in a phase relationship of I Fujian, the signals are sent to the combining subpath 25 of the horizontal polarization channel. On the other hand, the modulated signal at the main tap is output as is and input to the vertical polarization channel combining circuit 36.

In the horizontal polarization channel combining circuit 25, the modulation signal from the main tap of the transversal filter in the horizontal polarization channel described above and the modulation signal sent from the orthogonal coupling circuit 35 in the vertical polarization channel are input. The signals are combined and output to a predetermined demodulating means via a terminal 116. Similarly, in the vertical polarization channel combining circuit 36, the transversal signal in the vertical polarization channel described above is
The modulated signal from the main tap of the filter and the modulated signal sent from the orthogonal coupling circuit 24 in the horizontal polarization channel are input, combined, and outputted to a predetermined demodulating means via the terminal 124. The details of the cross-polarization interference removal effect regarding both the horizontal and vertical polarization channels mentioned above are specified in, for example, Japanese Patent Application No. 56-055529 and Japanese Patent Application No. 56-0555309, and can be found here. I will omit it here.

In the case of the above-mentioned conventional example, in order for the transversal filters provided in each of the horizontally polarized and vertically polarized channels to function effectively and appropriately in terms of cross-polarization interference removal, as is well known, Just like when applied to an automatically adaptive equalizer, the phase shift of the phase rotation amount of the input modulated signal carrier wave from 2 to π (k is a positive integer) radian in its main component, the delay circuit. Quantity ΔQ
(radians) is -Σ〈 in each delay circuit
It is a necessary condition that ΔQ<f. But from orange,
In practice, due to input modulation (frequency fluctuation of the carrier wave in the i signal, etc.), the amount of phase rotation of the carrier wave in each delay circuit is not necessarily maintained so that the conditional inequality of −1 ΔQ < is satisfied as described above. As a countermeasure for this, in the conventional example shown in FIG. 3, each tap and each variable type fitting corresponding to that tap are A phase correction cable of a predetermined length is inserted between each.

Cables 17-1 to 2 in Figure 3.18-1 to 2゜19-1 to 2.28-1 to 2, 29-1 to 2 and 3
Those are 〇-1~2. By adding these cables, the amount of phase rotation in the delay circuit is corrected, and the intended function of the cross-polarization interference cancellation circuit is achieved. However, these cables are extra circuit components that do not need to be added and should be eliminated as much as possible.

Moreover, the cable length adjustment needs to be short enough not to impair the cross-polarization interference removal effect of the transversal filter, and the amount of phase correction is required to adjust the cable length. It has the disadvantage of requiring a large amount of time in relation to accuracy.

The object of the present invention is to eliminate the above-mentioned drawbacks by controlling and adjusting the complex phase angle of the tap coefficient corresponding to a particular tap of each tap of a transversal filter, without using any extra cables. The amount of phase rotation of each delay circuit in the transversal filter can be corrected very easily, and an algorithm based on the ZF method can be applied, thereby improving both performance and economic aspects of cross-polarization interference removal. It is proposed to provide a cross-polarization interference cancellation circuit that is significantly improved.

The cross-polarization interference removal circuit of the present invention receives a transmission signal formed by two mutually orthogonal polarization components, and corresponds to at least one of the two polarization components. (2N+1) tap intermediate frequency band transversal formed by 2N (N is a positive integer) delay circuits for the purpose of removing cross-polarization interference caused by other orthogonal polarization components from the received signal. - In a cross-polarization interference removal circuit comprising a pair of filters, in each transversal filter of the pair of transversal filters, the intermediate frequency at 2N other taps based on the phase of the intermediate frequency modulation signal at the main tap. A predetermined phase adjustment means for controlling and adjusting a complex phase angle of a tap coefficient corresponding to a specific tap among the 2N other taps with reference to the phase of the modulation signal corresponds to the pair of transversal filters. be prepared and configured.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 2 is a conceptual block diagram showing the main parts of the present invention, and also clearly shows demodulation means related to the present invention. Further, FIG. 4 shows a case where the transversal filter, which is one of the main components of the present invention, is formed by two delay circuits, and includes a pair of transversal filters and a pair of synthesis circuits. FIG. 1 is a partial block diagram of an embodiment of the present invention.

As shown in FIG. 2, the present invention includes a transversal filter 7° phase adjustment means 10 and a synthesis circuit 12 in the horizontal polarization channel, and a transversal filter 8, phase adjustment means 11 in the vertical polarization channel. and a combining circuit 13, and control signal generating means 9 formed by horizontal polarization control signal generating means 9-1 and vertical polarization control signal generating means 9-2. Obviously, the major difference from the conventional example shown in FIG. This is achieved by providing phase adjustment means 10 and 11, respectively, between the means 9 and the means 9. Note that the demodulation means 14 related to the present invention includes respective combining circuits 12 and 13 in both polarization channels, which are part of the configuration of the present invention.
It is shown connected to.

As shown in FIG. 4, the transversal filter and synthesis circuit forming part of an embodiment of the invention also includes phase adjustment means 37 in the horizontal polarization channel;
Delay circuits 38 and 39 and variable weighting circuit 40-1
~2.41-1~2 and 42-1~2 and adder circuit 4
3-1 to 3-2, an orthogonal coupling circuit 44, and a combining circuit 45, and a phase adjustment means 46 in the vertical polarization channel.
, delay circuits 47 and 4B, and variable stop circuit 49
-1-2.50-1-2 and 51-1-2, adder circuits 52-1-2, and orthogonal coupling circuit 54.

The operation of the present invention will be explained below with reference to FIGS. 2 and 4.

In FIG. 2, horizontally polarized and vertically polarized intermediate frequency modulated signals BW and BN inputted from terminals 105 and 106, respectively, are inputted to transversal e-filters 7 and 8, respectively. Transversal number filters 7 and 8 output modulated signals BW and Sz, and output them to synthesis circuits 13 and 12, respectively.

Moreover, the modulation signals Bp and S' of the horizontal polarization component and the vertical polarization component output from the main taps of the transversal filters 7 and 8! are input to the synthesis circuits 12 and 13, respectively, and in the synthesis circuit 12, the
X,! :B1, 1 are combined to generate the modulated signal S3 of the horizontal polarization channel, and in the combining circuit 13, the BW and Sy are combined to generate the modulated signal BX of the vertical polarization channel. These modulation signals S output and Sv
are both input to the modulation means 14, and the corresponding demodulated signals 3H and 3X are outputted via terminals 107 and 108, and at the same time, specific signals BH and Sz including a predetermined demodulated signal and an error signal are outputted. and sends them to vertical polarization component signal generation means 9-1 and horizontal polarization control signal generation means 9-2, respectively. In the horizontal polarization control signal generation means 9-1, (
2N+1) tap coefficients corresponding to the transversal filter (n=-N, -N+l,...
, -1, 0, 1, . . . , N-1, N) are generated and input to the phase adjustment means 10. This tap coefficient C1 is given by the following equation when expressed in the form of the above-mentioned in-phase control signal and quadrature control signal.

Bow = Bow + J dH (1) In the above formula, j=r]-.

In the phase adjustment means 10, the cH (also referred to as cH) is converted. As a result, the tap coefficient shown in equation (1) is converted as shown in the following equation.

The tap coefficient Cn (or the in-phase control signal bow and the quadrature control signal gH) to which the phase shift of θan (radians) given by the above equation (2) is outputted from the phase control means 10 and The variable weightings corresponding to each tap are sent to the versal filter 7 and input into the circuit respectively. Similarly, in the vertical polarization control signal generation means 9-2, tap coefficients Cv (n=-N, -N+1, etc.) corresponding to the transversal filter 8 of (2N+1>tap) in the vertical polarization channel are ..., -1,0
, 1, . . . , N-1, N) are generated and input to the phase adjustment means 11. Corresponding to the above equation (1), the tap coefficient CW for the transversal filter 8 is expressed by the following equation.

C:1-rn+jdn(3) Furthermore, a predetermined phase shift expressed by ejan is given to CX (or in-phase control signal rX and quadrature control signal dX) as in the above case, and the above (3 ) is converted as shown below.

The tap coefficient C/X (or the in-phase control signal iV and the orthogonal control signal, IX) given the phase shift of θan (radians) expressed by the above equation (4) is output from the phase adjustment means 11 and is - Sent to filter 8, the town change weighting corresponding to each tap is input into the circuit respectively.

In other words, the main points different from the conventional example shown in FIG.
In the present invention shown in FIG.
and 11, and by adjusting the phase of the tap coefficients C (: and Cx) for the corresponding Tonon Sversal filters 7 and 8, the addition of a cable for phase adjustment, which is a disadvantage of the conventional example described above, is eliminated. In particular, by using such a phase adjustment action, the phase shift amounts θan (radians) and θan (Fugians) are appropriately set, and the algorithm conformity conditions regarding the transversal filters 7 and 8 are established. Achieve the desired cross-polarization interference cancellation function.

In the cross-polarization interference cancellation circuit of the present invention described above.

■ θan (radians) in equations (2) and (4)
By substituting -77 cyan and π radian for and θan (radian), the following equation is obtained.

(θan=±72) (θan−±−) Therefore, as is clear from equations (5) and (6),
The phase shifts θin (radian) and θan (2 dian) for the tap coefficients CIA and eV corresponding to transversal filters 7 and 8 are calculated for each predetermined tap, provided that the above-mentioned algorithm compliance conditions are met. One cloud radian, i fusian and π
By selecting any value in radians, the in-phase control signal and quadrature control signal for each tap can be clearly set with reference to equations (5) and (6). In other words, if the algorithm of the transversal filter can be maintained by the phase shift in radians) and θan (radians), then (5) above
By inputting the in-phase control signal and quadrature control signal set by Equation and Equation (6) into the circuit, the predetermined variable weighting on the in-phase side and the orthogonal side of the transversal filter, respectively, satisfies the algorithm compliance conditions. It is possible to realize the cross-polarization interference removal effect using the transversal filter.

Of course, the operation of exchanging the in-phase side control signal and the orthogonal side control signal can be done by simply using the control signal as it is, connecting it to the circuit for variable weighting, and connecting the output of the circuit for in-phase side and quadrature side weighting, respectively.
This is equivalent to connecting the signal synthesis circuits on the orthogonal side and the in-phase side interchangeably.

FIG. 4 shows the case where the transversal filter is formed by two delay circuits, as described above, that is, N=
In case 1, as mentioned above, K (5) and (6)
FIG. 2 is a partial block diagram of an embodiment of the present invention in which the phase of tap coefficients is adjusted in steps of 7 fcyans with reference to the formula.

In FIG. 4, terminal 125 in the horizontal polarization channel
A horizontally polarized modulated signal 8H is inputted from the input terminal, and modulated signals S2 (=4), Sv and SsB of each tap corresponding to each terminal of the delay circuits 38 and 39, and variable weights are respectively applied on the in-phase side. Attached is circuit 40-1.41
-1 and 42-1, and on the orthogonal side, variable weighting is applied to circuits 4o-2, 41-2 and 42-1, respectively.
-2 is input. On the other hand, the horizontal polarization control signal, Y, rF
and r7 and quadrature control signal dW.

dl and d\ are input to the phase adjustment means 37 via terminals 126, 128 and 130 and terminals 127, 129 and 131, respectively, and the phase adjustment means 37 adjusts the above-mentioned (5
), the in-phase control signals −Pi −H r−3, rQ, and rl of each tap and the quadrature control signals d1 . d
, and maki, respectively, and the in-phase side variable weighting is circuits 40-1, 41-1 and 42-1, and the orthogonal side variable weighting is circuits 40-2, 41-2 and 42-2. is input as a predetermined control signal. Modulated signal B4 at each tap. BM and SP are weighted by the respective control signals in the circuit with the above-mentioned corresponding variable weighting on the in-phase side and the quadrature side, and the modulation signals "j t SW and S7 and the modulation signal H'H'
H' 8-1 , 86 oyohi 8 t is output. On the in-phase side, the modulated signal s4. 10- and sW are added to generate a modulated signal Sr, which is input to the orthogonal coupling circuit 44, and on the orthogonal side, the modulated signal 8-1 .
So and Sl are added to generate a modulated signal Si, which is input to the orthogonal coupling circuit 44. In the orthogonal coupling circuit 44, these modulated signals S.

and 8i are combined with each other in a phase relationship of 77 cyan, and the output modulated signal SB is sent to the vertical polarization channel combining circuit 54. On the other hand, the modulated signal So at the main tap is output as is and input to the horizontal polarization channel combining circuit 45.

Similarly, on the vertical polarization channel side, terminal 1
A vertically polarized modulated signal SA is input from 33, and each 1'y7' corresponding to each terminal of delay circuits 47 and 48
tD'klF4'tM No.5-Y(=SX)v8XOyoU
8Y is input to variable weighting circuits 49-1.50-1 and 51-1 on the in-phase side, and variable weighting circuits 49-2.50-2 on the orthogonal side, respectively.
and input to 51-2. On the other hand, vertical polarization control
In-phase control signals r-1 and r6 sent from the signal light generation stage
and rl, and orthogonal control signals d-1, do and dl are terminals 134, 136 and 138 and terminal 1, respectively.
35, 137 and 139, the phase adjustment means 46
and the in-phase control signal r-1tr of each tap is input to the phase adjustment means 46 via the above equation (6) in accordance with the above-mentioned algorithm compatibility condition.

and 1ri, and orthogonal control signals d-1, do and dl, respectively, and weighting on the in-phase side is performed by circuit 49-1.
50-1 and 51-1, and the weighting on the orthogonal side is performed by the circuit 49.
-2.50-2 and 51-2 as a predetermined control signal. Modulation signal S at each tap
Δv8X and BY are weighted by the respective control signals in the circuit in which the above-mentioned phase-corresponding variable weighting on the in-phase side and quadrature side is applied to the modulated signal 8-Y t S
O and 100Y are output as modulated signals 100X'L5F and Sl. On the in-phase side, the modulation signals S, , S are input in the adder circuit 52-1.

and BY are added to generate a modulated signal SV, which is input to the orthogonal coupling circuit 53. On the orthogonal side, the modulation signal is 94° in the adder circuit 52-2.

100 Y' and R1 are added to generate a modulated signal SY, which is input to the orthogonal coupling circuit 53. Orthogonal coupling circuit 53
, these modulated signals S\ and BY are combined with each other in a phase relationship of p-gian, and the output modulated signal BX is sent to the horizontal polarization channel combining circuit 45.

On the other hand, the modulated signal S0 at the main tap is output as is and input to the vertical polarization channel combining circuit 54.

As mentioned above, the modulated signals Bp and B generated in the horizontal polarization channel and the vertical polarization channel, respectively.
Regarding the modulation signals BY and SX, in the horizontal polarization channel combining circuit 45, the modulation signals SF and S
X is synthesized, and the vertical polarization channel synthesis circuit 5
4, the modulated signals BY and BW are combined and output as modulated signals sH and Sv, respectively, through terminals 132 and 140 CC. These modulation signals Blj and BV
It goes without saying that the differential polarization interference signal is removed in each case. In the above-described embodiment of the present invention, a phase step of ±i radians and π radians is used to correct the phase rotation of the carrier wave of the input modulation signal in the delay circuit of the transversal filter. It goes without saying that the present invention is not limited to the above-mentioned phase step correction of ten cloud radians and π radians, but can generally be effectively applied to phase correction of any phase amount.

Further, the present invention is applied to correct the phase rotation of the carrier wave of the input modulation signal in the delay circuit of the transversal filter described above, and the complex phase angle of the tap coefficient for a specific tap of the transversal filter is adjusted. In order to do this, it is also possible to form a desired cross-polarization interference cancellation circuit using a predetermined length of cable.

As explained in detail above, the present invention provides a cross-polarization interference removal circuit including a transversal filter.
By controlling and adjusting the complex phase angle of the tap coefficient for a specific tap in the transversal filter, it is possible to apply the ZF algorithm very easily, and it is improved both in terms of performance and economy related to adjustment man-hours. , has the effect of being significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a conceptual block diagram of a conventional cross-polarization interference cancellation circuit, FIG. 2 is a conceptual block diagram of the present invention, and FIG. FIG. 4 is a block diagram showing the main parts of an embodiment of the present invention excluding the control signal generating means. In the figure, 12, 7.8... transversal filter, 3, 9... control signal generating means,
3-1.9-1...Horizontal polarization control signal generation means, 3-2゜9-2...Vertical polarization control signal generation means, 4, 5, 12゜13. 25, 36. 45, 54...
...Composition circuit, 6, 14...Demodulation means, 1
0,11,37.46... Phase adjustment means, 15
,16,26,27,38,39,47.48...
...Delay circuit, 17-1 ~ 2.18-1 ~ 2.19-1
~2゜28-1~2.29-1~2.30-1~2...
... Cable, 20-1 ~ 2.21-1 ~ 2.22
-1～2.31-1～2゜32-1～2.33-1～2
．． 40-1~2.41-1~2゜42-1~2.49-
1~2.50-1~2.51-1~2...Variable weighting is a circuit, 23-1~2.34-1~2,43-1
~2.52-1~2... Addition circuit, 24, 35
, 44゜53... Orthogonal coupling circuit.

Claims (3)

[Claims] (1) Receive a transmission signal formed by two mutually orthogonal polarization components, and select the other orthogonal polarization component from the received signal corresponding to at least one of the two polarization components. With the aim of eliminating cross-polarization interference caused by
Formed by 2N (N is a positive integer) delay circuits (
2N+1) In a cross-polarization interference cancellation circuit comprising a pair of tap intermediate frequency band transversal filters,
In each transversal filter of the pair of transversal filters, the phase of the intermediate frequency modulation signal at the 2N transversal taps is determined based on the phase of the intermediate frequency modulation signal at the main tap. Cross-polarization interference removal characterized in that the pair of transversal filters is provided with a predetermined phase adjustment means for controlling and adjusting the complex phase angle of a tap coefficient corresponding to a specific tap among the transversal filters. circuit. (2) The predetermined phase adjustment means has a phase adjustment function with a step of 100 degrees, and in order to realize this phase adjustment function, the in-phase side and quadrature side of the specific tap that is the target of phase angle adjustment. According to claim (1), the variable weighting sets the input distribution and polarity of the in-phase control signal and quadrature control signal to the circuit in accordance with the phase angle adjustment of the -Fugian step. The cross-polarization interference removal circuit described. (3) The predetermined phase IAI adjustment means has a phase angle adjustment function with a step of niradian, and in order to realize this phase angle adjustment function, it corresponds to the specific tap coefficient that is the target of phase angle adjustment. The polarities of the in-phase control signal and the quadrature control signal for the in-phase and quadrature side variable weighting circuits of the taps to be output, and the outputs of the in-phase and quadrature side variable weighting circuits, are used as signals on the quadrature side and in-phase side, respectively. , the cross-polarization interference canceling circuit according to claim 1, wherein the cross-polarization interference canceling circuit is set to correspond to the phase angle adjustment in radian steps in front of the sign by performing a switching operation.