JPS637053B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In addition to receiving signals from a master station such as a broadcaster or a relay broadcaster, the present invention is capable of affecting the reception band by reflected waves from other stations or countries, such as the ionosphere. The present invention relates to an interference wave removal reception method used to remove interference waves that give rise to interference waves.

Generally, in order to remove beat interference waves using the phase difference feeding system, as shown in Fig. 1, a plurality of antenna systems 1 to 3, each consisting of two or more antennas, are arranged in a straight line. The systems 1 to 3 are provided with amplitude variable devices 4a to 4c and phase shifters 5a to 5c, and the received waves of each antenna system 1 to 3 are combined by a combiner 6 to obtain an output 6a.

When combining the received waves from each of the antenna systems 1 to 3, the amount of phase shift by the phase shifters 5a to 5c and the amount of amplitude by the variable amplitude devices 4a to 4c are changed to combine the desired wave components in the same band. The amounts of phase shifters 5a to 5c and amplitude variable devices 4a to 4c of each antenna system 1 to 3 are determined so that the combined amplitude of only the interference waves becomes zero without canceling them out.

According to such a phase difference feeding method, in order to cancel interference waves, it is necessary to uniquely determine each amplitude amount for combining the phase shift amount (0° to 360°) of each phase shifter 5a to 5c. Furthermore, it is difficult to adjust because there are too many parameters.

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional technology. At least three antennas are arranged at equal intervals, and desired waves are received at equal distances with the same phase and amplitude. , when the interference wave is received at an angle θ with the desired wave, invert/in-phase and amplitude control is performed only on the received input component from the central antenna among the three antennas,
It is an object of the present invention to provide an interference wave elimination reception method that can eliminate interference waves by combining received signals from three antennas.

Embodiments of the interference wave removal reception system of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram for explaining the operating principle of one embodiment, and this will be explained first. In FIG. 2, the same parts as in FIG. 1 will be described with the same reference numerals. Each of the receiving antennas 1a to 3a arranged in a straight line has a frequency converter 8.
a to 8c are provided, and this frequency converter 8
a and 8c are connected to the combiner 6.

Further, the frequency converter 8b is connected to a 0° phase shifter 7a and a 180° phase shifter 7b of the phase shifter ₇ via a switch S1. In other words, switch S ₁ is a movable terminal
S ₁ a and two fixed terminals S ₁ b, S ₁ c, the movable terminal S ₁ a is connected to the output side of the frequency converter 8b, and the fixed terminals S ₂ b, S ₂ c are connected to 0゜Phase shifter 7a,
It is connected to a 180° phase shifter 7b.

In addition, the 0° phase shifter 7a is the fixed terminal of switch _S2.
S ₂ b, and the 180° phase shifter 7b is connected to the fixed terminal S ₂ c. A movable terminal S ₂ a of the switch S ₂ is connected to the synthesizer 6 via an amplitude regulator 9 .
An output 6a is taken out from the combiner 6.

Next, the operation shown in FIG. 2 will be explained. Figure 3 shows the desired wave, interference wave, and receiving antenna 1a~
In this figure, there is an equal distance d between receiving antennas 1a and 2a, and between 2a and 3a, and the angle of arrival of interference wave 12 and desired wave 11 is When the angle is θ, the reception phase difference of interference waves caused by the difference in electrical length is between receiving antennas 1a and 2a as follows: = d・(sinθ)(2π/C _B ) (1), and between receiving antennas 1a and 2a, 3a, it is clear that '=2d(sinθ)(2π/C _B )...(2).

In equations (1) and (2), _B indicates the frequency of the interference wave.

At this time, if the vector representation of the interference waves generated at the receiving antenna 1a is B ₁ =b・(1+j・0)...(3) (where b=|B ₁ |), then the interference waves generated at the reception antennas 2a and 3a are are respectively expressed as B ₂ =b(cos+jsin)...(4) _B3 =b(cos2+jsin2)...(5).

As shown in Figure 4, there are only two cases in which to combine the interference waves B ₁ to _{B 3} in equations (3) to (5) above and make their amplitude components zero, as shown below. It's so obvious. That is, the two cases are (i) when φ≦π/2 (Fig. 4 a), and (ii) when π/2 < φ < (3/2) π (Fig. 4 b). be.

Next, when combining the components of the receiving antennas 1a, 2a, and 3a, considering that only the amplitude of the component of the receiving antenna 2a is changed by a value of m times, let the vector after combining by the combiner 6 be E _B. , E _B =B ₁ +B ₃ +m・B ₂ = (1+cos2φ+m cosφ)+
j(sin2φ+m sinφ)...(6) (m is a scalar quantity). However, the amplitude of this composite vector E _B is
B This is a vector generated by _one vector, and the same applies below.

This power is |E _B | ² = (m+2cosφ) ² (7).

Here, in order to make the combined vector E _B , that is, the output of the interference wave, zero, by setting |E _B | ² =0 from equation (7), m=-2cosφ (8) is obtained.

Here, in equation (8), when φ≦π/2, m<
0, which means that the phase of the interference wave component to the receiving antenna 2a is shifted by 180°, as is clear from Fig. 4a, and similarly, π/2<φ≦(3/2).
When π, m>0, which means that the phase of the interference wave component to the receiving antenna 2a is shifted by 0°, as is clear from FIG. 4b.

In this way, the three receiving antennas 1a to 3a are positioned at equal intervals, and the arrival angle θ of the interference waves (Fig. 3)
Once determined, the interference wave level can be reduced to zero by the phase shift amount (0° and 180°) of the central receiving antenna 2a and the variable amplitude amount m determined by this arrival angle θ, and the adjustment , settings can be easily performed.

Furthermore, as shown in FIG. 2, when performing phase difference synthesis, the same effect can be achieved even if frequency conversion is performed by frequency converters 8a to 8c.Furthermore, in FIG. The outputs of the receiving antennas 1a and 3a are combined (by the combiner 6), but the result is the same even if the outputs of the receiving antenna 2a system are combined after combining the receiving antennas 1a and 3a. It goes without saying that the same applies to other combinations of synthesis methods.

Next, an embodiment of the present invention will be described with reference to FIG. Note that in FIG. 5, the same reference numerals are used for parts corresponding to those in FIG. 2. In this FIG. 5, the first, second, and third receiving antennas 1a to
3a are arranged at equal intervals and are provided with frequency converters 8a to 8c, respectively, and distributors 12a to 12c. Distributor 12
a, 12c are connected to a combiner 6, and an output 6a is taken out from the combiner 6.

The outputs of the distributors 12a and 12b are sent to a combiner 13a, and the outputs of the distributor 12a and 12b are sent to a combiner 13a.
The outputs of a and 12c are sent to a combiner 13b. The outputs of both combiners 13a and 13b are sent to an arithmetic unit 14, and the output of this arithmetic unit 14 is sent to a controller 15. The controller 15 controls the phase shifter 7 and adjusts the amplitude adjuster 9 based on the output of the arithmetic unit 14.

Further, the output of the distributor 12b is sent to the phase shifter 7. This phase shifter 7 is adapted to perform a phase shift of 0° or 180°. The output of the phase shifter 7 is passed through the above-mentioned amplitude adjuster 9 to the synthesizer 6.
It is now being sent to

As mentioned above, the output of the interference wave becomes zero when m = -2cos, and the amount (the value of m, including the sign) that controls the output of the receiving antenna 2a is the angle of arrival θ.
It can be determined uniquely by knowing.

Next, a means for detecting the equivalent angle of arrival of interference waves to the receiving antenna will be described. First, when the outputs of receiving antennas 1a and 2a are inverted by the distributor 12b and combined by the combiner 13a, the desired waves are received in the same phase and amplitude. , the desired wave is synthesized in reverse phase, so the output is zero, and the power of only the interference wave is |E ₁₂ | ² = (1-cos) ² + sin ² = 2-2cos
…(9) becomes.

Furthermore, when the outputs of the receiving antennas 1a and 3a are inverted by the distributor 12c and combined by the combiner 13b, the output of the desired wave becomes zero, and the power of only the interference wave is obtained. E ₁₃ | ² = 2−2cos(2) …(10).

From |E ₁₂ | ² and |E ₁₃ | ² , γ=|E ₁₂ | ² + |E ₁₃ | ² / |E ₁₂ | ² is obtained, and γ=3+2cos...(11) is obtained.

Substituting the value of m mentioned above into this, we get m=-γ+3...(12) is obtained.

As mentioned above, γ is a function of the angle of arrival θ, so the fact that we were able to obtain the value of γ means that the angle of arrival θ
It is clear that the value of m obtained from this value of γ, including the sign, becomes the control amount of the system.

In addition, this analysis considered only when there is one interference wave, but even when there are two or more interference waves, regardless of the frequency of the interference wave, γ obtained by detecting the power of the interference wave, Determine m. It can be easily confirmed that the highest degree of interference wave rejection can be obtained by employing equation (12) as the calculation formula for m and γ.

In other words, when there is only one interference wave, an infinite value of rejection can be obtained, but when there are two or more interference waves, it is impossible to obtain infinite rejection for all interference waves. One can easily guess that. This optimal rejection degree varies depending on the frequency interval of the interference wave, and also changes depending on the angle of arrival θ, but γ
Equation (12) holds true between (equivalent arrival angle) and m (amplitude variable ratio), and this is the maximum value of the degree of removal.

As is clear from the above, in this embodiment, if the value of m is controlled each time by measuring γ representing the equivalent angle of arrival, even if the angle of arrival of the interfering wave changes from time to time, Each time, γ is measured, and the arithmetic unit 14 calculates the variable amount of the phase shifter 7 and the amplitude adjuster 9. Based on the calculation result, the controller 15 is operated to adjust the phase shifter 7 and the amplitude adjuster 9. By doing so, it is possible to control the value of m in real time and remove interference waves.

In addition, in FIG. 5, similar to FIG. 2, the combiner 6 is used to combine the three waves at once, but this means that after combining the receiving antennas 1a and 3a, they are combined with the receiving antenna 2a. The result is the same even if it is synthesized using other combinations. Furthermore, the arithmetic unit 14 and the controller 15 can be easily realized using a microcomputer or the like.

As described above, according to the interference wave removal reception method of the present invention, three receiving antennas are arranged at equal intervals, and desired waves are received at the same distance with the same phase and amplitude. When an interfering wave is received at a predetermined angle with the desired wave, only the received input component from the central receiving antenna is inverted or in phase, and amplitude control is performed to adjust the received signals from the three receiving antennas. The arrival angle is detected from each reception output, and control is performed by calculating the above-mentioned inversion or in-phase control and amplitude control amount, thereby achieving the effect that interference waves can be completely removed in real time.

[Brief explanation of the drawing]

Figure 1 is a system diagram of the conventional phase difference feeding system, Figure 2
The figure is a block diagram for explaining the operating principle of the interference wave removal receiving system of the present invention, FIG. 3 is a diagram showing an example of the arrangement of the receiving antenna in FIG. 2, and FIGS. A diagram showing an example of vector synthesis for combining the interference waves in FIG. 2 and making their amplitude components zero, and FIG. 5 is a block diagram showing an embodiment of the interference wave removal receiving system of the present invention. 1a to 4a...receiving antenna, 6...combiner, 7...
Phase shifter, 9... Amplitude adjuster, 12a-12c... Distributor, 13a-13b... Combiner, 14... Arithmetic unit, 1
5...Controller.

Claims (1)

[Claims] 1. First, second, and third receiving antennas arranged at equal intervals so as to have the same phase and amplitude at the same distance from the desired wave, and the first, second, and third receiving antennas. a phase shifting means for in-phase or inverting the phase of the received input component from the second receiving antenna located at the center of the second receiving antenna; a level adjusting means for changing the amplitude level of the received wave phase-shifted by the phase shifting means; a first combining means for combining received wave components from the means and received wave components from the first and third receiving antennas; second and third combining means for subtracting the received waves, respectively; and detecting an equivalent interference arrival angle from the combined reception waves from these combining means, and adjusting the level with the phase shifting means based on the equivalent interference arrival angle. An interference wave removal receiving system comprising: a calculation means for determining a variable amount for changing the means; and a controller for controlling the phase shifting means and the level adjustment means using the variable amount determined by the calculation means.