JPH03123124A - Two-band satellite receiver - Google Patents

Abstract

PURPOSE:To improve the noise suppression effect with simple constitution by providing a variable polarization plane converter and a polarizer/demultiplexer, and separating and leading a high frequency signal received by an antenna into a low noise converter having an appropriate band characteristic. CONSTITUTION:The receiving band of a low noise converter 43 and the receiving band of a low noise converter 44 are set as a band 1 and a band 2, respectively. In such a state, in the case of receiving the V polarized wave of the band 1, a variable polarization plane converter 41 is not brought to rotation control, its output is inputted to a polarizer/demultiplexer 42 in a state that it remains the V polarized wave as it is, the V polarized wave is led out of the polarizer-demultiplexer 42, and it is inputted to a low noise converter 43 having the receiving band of the band 1. On the other hand, in the case of receiving the V polarized wave of the band 2, the plane of polarization of the variable polarization plate converter 41 is rotated by 90 deg. and the V polarized wave is converted to an H polarized wave, and led into a low noise converter 44. In such a manner, a high frequency signal received by an antenna 40 can be separated and led into the low noise converter having an appropriate band characteristic in accordance with the plane of polarization and the band, and the noise suppression effect can be improved by the simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a dual-band satellite receiver that receives high-frequency signals in the microwave band.

(Prior Art) In recent years, communication and broadcasting services are being provided in Japan and in Western countries using communication satellites and broadcasting satellites whose downlinks are in the Ku band.

In order to use these services, basically the seventh
A receiver as shown in the figure is required.

In FIG. 7, the output of the parabolic antenna 1 is guided to a polarization converter 2, and the output of the polarization converter 2 is input to a low noise converter 3. The polarization converter 2 selects a plane of polarization. In the low-noise converter 3, the signal from the polarization converter 2 is amplified by a low-noise amplifier 31, and the amplified output is supplied to a mixer 32. Mi, the wedge 32 is supplied with local oscillation from the local oscillator 33;
As a result, an intermediate frequency signal converted to an intermediate frequency is obtained. This intermediate frequency signal is amplified by an intermediate frequency amplifier 34 and then introduced into an indoor tuner 4. here,
The user selects the desired channel. The channel signal selected by the tuner 4 is input to a terminal (for example, a television monitor) 5.

However, in satellite communications and broadcasting systems, frequency bands, polarization planes, and satellite positions may differ depending on the service. If you want to receive multiple service signals in this situation, the first method is to use multiple receivers. However, this method requires a large installation space for the receiving equipment and is costly. The second method is to use a receiver capable of receiving two bands as shown in FIG.

In FIG. 8, 10 is a parabolic antenna, and the output of this parabolic antenna [0] is guided to a variable polarization plane converter]. The parabolic antenna 10 has an actuator 2
0 and is controlled to point in the direction where the desired satellite is located. An antenna control signal is supplied to the actuator 20 from a terminal 21 . Also, variable polarization plane converter]
], the reception polarization plane is switched so as to select the polarization plane of the high frequency wave received by the antenna 10. This switching is performed by a polarization plane switching signal from the terminal 22.

The high-frequency signal selected in this way is introduced into a wideband low-noise amplifier 13 that constitutes a low-noise converter 12.

Here, the output terminal of the wideband low noise amplifier 13 is connected to two bandpass filters 14A and 14B, each having a different pass band.
It is connected to the. and each band filter 14A and 14
The outputs of B are supplied to mixers 15A and 15B, respectively. Each mixer 15A and 15B has a local oscillator 16A and 1
The output from 6B is supplied. As a result, mixer 1
An intermediate frequency signal can be obtained from 5A and 15B.

The intermediate frequency signals from mixers 15A and 15B are configured to be supplied to intermediate frequency amplifiers 17A and 17B, respectively.

According to the receiver shown in FIG. 8, it is necessary to design the low noise amplifier 13 to have wideband characteristics. However, it is difficult to realize a low-noise amplifier that covers two bands. Furthermore, since the output of the low noise amplifier 13 is divided by the two bandpass filters 4A and 14B, good division becomes difficult when the transmission bands are close to each other.

(Problem to be solved by the invention) As explained above, in the conventional receiving system,
When trying to receive multiple service signals with different frequency bands, polarization planes, and satellite positions, preparing multiple receivers poses problems in terms of installation space and high costs.
The above-mentioned two-band receiver has problems in terms of low-noise amplifier design and high-frequency signal separation.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a low-cost two-band satellite receiver that has an excellent noise suppression effect with a simple configuration.

(Means for Solving the Problems) The present invention provides a variable polarization plane converter that is supplied with a high frequency signal input from an antenna and capable of converting the polarization plane of the high frequency signal; A polarization demultiplexer that demultiplexes the output according to the plane of polarization, and first and second low-noise converters each supplied with the high frequency demultiplexed by the polarization demultiplexer and each having a different reception band. , means for controlling the variable polarization plane converter according to the band and polarization plane of the high frequency signal input from the antenna, and selectively supplying the input high frequency signal to the first and second low noise converters. It is something to be prepared for.

(Function) By providing a variable polarization converter and a polarization demultiplexer as in the above means, by combining the selected polarization plane and the derivation direction, the high frequency signal received by the antenna can be changed to a polarization plane. It can also be separately introduced into a low-noise converter with appropriate band characteristics depending on the band.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. The output of the parabolic antenna 40 is input to a variable polarization plane converter 41. The direction of the parabolic antenna 40 is controlled via an actuator 46 by a control signal supplied from a terminal 45 so as to point, for example, in the direction of a broadcasting satellite. Further, the variable polarization plane converter 41 is switched by a control signal supplied from a terminal 47 so as to select the polarization plane of the high frequency wave that the antenna 40 is receiving.

The variable polarization plane converter 41 has a configuration as shown in FIG. 2, for example. That is, the ferrite rod 6 inside the circular waveguide 61
This is a type in which the direct current magnetic field applied to 2 is changed by an electromagnet 63 to rotate the plane of polarization. In this example, 9
The rotation angle can be changed from 0°.

The output of the variable polarization plane converter 41 is input to a polarization splitter 42. This polarization splitter 42 has a configuration as shown in FIG. 3, for example.

That is, high frequency waves are supplied to one end of the circular waveguide 71.

A first rectangular waveguide 72 is provided at the other end of the circular waveguide 71, and a second rectangular waveguide 73 is provided at a part of the circumference of the circular waveguide 71 in a direction perpendicular to the axis. is installed. A shorting rod 74.75 is arranged in front of each waveguide 72.73. Now, let us say that the elongated direction of the rectangular opening of the first rectangular waveguide 72 is the polarization plane of H polarization, and the direction perpendicular to this is the polarization plane of V polarization. Then, if the polarization plane of the signal input to the circular waveguide 71 is ■ polarization, an output signal is obtained from the first rectangular waveguide 72, and if the polarization plane of the input signal is H polarization, , an output signal is obtained from the second rectangular waveguide 73.

Low noise converters 43 and 44 having different reception bands are connected to the output ends of the rectangular waveguides 72 and 73, respectively. Here, the reception band of the low-noise comparator 243 is band 1, and the reception band of the low-noise converter 44 is band 2. The configurations of low noise converters 43 and 44 are similar. The first rectangular waveguide 72 and the second rectangular waveguide 73 of the polarization splitter 42
The outputs of are input to low noise converters 431 and 442, respectively. The outputs of low noise converters 431 and 442 are fed to mixers 432 and 442, respectively. Mixers 432 and 442 are supplied with respective outputs of local oscillators 433 and 443. Therefore, mixers 432 and 44
2, an intermediate frequency signal can be obtained. mixer 4
The respective outputs of 32 and 442 are connected to intermediate frequency amplifiers 434 and 44.
4 and output terminals 435 and 445, respectively.
It is structured so that it is derived as follows.

Here, when receiving V-polarized waves in band 1, the variable polarization plane converter 41 is set so that its output is inputted as V-polarized waves to the polarization splitter 42 without rotation control. .

Then, when receiving V-polarized waves in band 1, polarization splitter 4
The V-polarized wave is derived from the first rectangular waveguide 72 of No. 2 and input to the low-noise converter 43 having a reception band of band 1. This makes it possible to receive V-polarized waves in the first band.

When receiving the polarized wave of band 2, the polarization plane of the variable polarization plane converter 41 is rotated by 90 degrees.

This converts the V polarization into H polarization. Therefore, since the input signal of the polarization splitter 42 is H-polarized, it is introduced into the second low-noise converter 44. Therefore, reception processing of V-polarized waves in band 2 is possible.

Furthermore, when receiving the H polarized wave of band 1, the polarization plane of the variable polarization plane converter 41 is rotated by 90 degrees from the normal setting state. This converts the H polarization into V polarization. Therefore,
Since the input signal of the polarization splitter 42 is V-polarized, it is introduced into the first low-noise converter 43. Therefore, reception processing of H polarized waves in band 1 becomes possible.

Furthermore, when receiving H polarized waves in band 2, the polarization plane of the variable polarization plane converter 41 is not rotated. Therefore, the H-polarized wave is output as it is, and the input signal of the polarization splitter 42 remains as the H-polarized wave, and is introduced into the second low-noise converter 44. Therefore, reception processing of H polarized waves in band 1 becomes possible.

The above can be summarized in a table as shown below.

0 As described above, according to this embodiment, the variable polarization plane converter,
By providing the polarization splitter, the high frequency signal received by the antenna can be separated and introduced into a low noise converter having appropriate band characteristics depending on the polarization and band.

The above embodiment shows a device that can receive high frequency signals in band 1 and band 2 when they are linearly polarized waves, but domestic C8
In some cases, one band is circularly polarized, as in the case of BS and BS.

If such a signal can be received, a configuration as shown in FIG. 4 may be used.

1 That is, the circular linear polarization converter 80 may be connected between the parabolic antenna 40 and the variable polarization plane converter 41. Fourth
In the figure, the same parts as in FIG. 1 are marked with the same symbols.

FIG. 5 shows an example of the configuration of the circular linear polarization converter 80.

The circular linear polarization converter 80 includes a circular waveguide 8] and a dielectric plate 8.
Consists of 2. The dielectric plate 82 is inserted in the diametrical direction of the circular waveguide 8 and parallel to the V-polarized wave or the circularly polarized wave. With this configuration, the V-polarized wave and the circularly polarized wave are output as they are. On the other hand, circularly polarized waves are
It is output as a linearly polarized wave having a polarization angle of 45° with respect to the V-polarized wave or the circularly polarized wave. Therefore, the variable polarization plane converter 41
If the plane of polarization is rotated by 45 degrees, the low noise converter 43
or 44, circularly polarized waves can be received.

Further, a polarization splitter 42 and a low noise converter 43 or 4
By making 4 an integral structure, the size can be reduced.

FIG. 6 shows a configuration in which a polarization splitter 42 and a low noise converter 43 are integrated. Inside the circular waveguide 91, there are a probe 92 and a shorting rod 93 that are parallel to the polarized wave.
A low-noise converter 43 unit formed of a microstrip line is connected to the probe 92. Further, a probe 94 is provided inside the circular waveguide 91 so as to be parallel to the circularly polarized wave, and the low noise converter 44 unit is connected to this probe 94. With this configuration, the V-polarized wave input into the circular waveguide 91 is received by the probe 92 and guided to the low-noise converter 43 unit. In addition, the circularly polarized signal is
The signal is received by probe 94 and directed to low noise converter 44 .

This embodiment includes a polarization splitter 42 and a low noise converter 43.
．． It has the same function as a combination of 44 and can be made smaller because it has an integrated structure without using a waveguide circuit.

[Effects of the Invention] As described above, the present invention has a simple configuration, has an excellent noise suppression effect, and can provide a low-cost receiver.

3

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of the structure of the variable polarization plane converter shown in FIG. 1, and FIG. 3 is a structure of the polarization demultiplexer shown in FIG. 1. FIG. 4 is a configuration explanatory diagram showing another embodiment of the present invention, FIG. 5 is a diagram showing an example of the structure of the circular linear polarization converter of FIG. 4, and FIG. Figures 7 and 8 showing still other embodiments are diagrams showing examples of conventional receivers, respectively. 40... Parabolic antenna, 41... Variable polarization plane converter, 42... Polarization splitter, 43.44... Low noise converter, 46... Actuator.

Claims (1)

[Claims] A variable polarization plane converter to which a high frequency signal input from an antenna is supplied and capable of converting the plane of polarization of the high frequency signal, and an output supplied from the variable polarization plane converter according to the plane of polarization. A polarized demultiplexer separates the waves, and the high frequency waves demultiplexed by this polarized demultiplexer are supplied, respectively.
first and second low-noise converters each having different reception bands; controlling the variable polarization plane converter according to the band and polarization plane of a high frequency signal input from the antenna;
, means for selectively supplying an input high frequency signal to the second low noise converter.