JPH11215018A - Antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna device capable of operating plural antenna amplifiers with the same voltage and also surely and easily deciding an antenna switching signal. SOLUTION: This antenna device 10 operates an active antenna, consisting of antenna elements 11a and 11b and amplifiers 12a and 12b with a prescribed voltage and sets the control signal which selects an antenna element at a voltage level lower than the prescribed voltage. Then the control signal is detected by a protection means 14, and the elements 11a and 11b are switched to each other synchronously with the internal clock of an antenna selection means 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device for switching a plurality of antenna elements.

[0002]

2. Description of the Related Art Conventionally, antenna devices,
And has been widely applied to receivers using satellites such as CS. An antenna device applied to this receiver generally includes a plurality of antenna elements, and these antenna elements are switched and used. In this receiver, a method of transmitting a radio wave transmitted from a satellite with right-handed circular polarization or left-handed circular polarization in order to effectively use the frequency and reduce radio wave interference is used.

[0003] The antenna device of the receiver has, for example, two types of antenna elements capable of receiving right-handed circularly polarized waves or left-handed circularly polarized waves, respectively. Alternatively, a left-hand circularly polarized radio wave is received.

An example of an antenna device having a function of selecting two types of antenna elements will be described below. FIG. 4 shows a block diagram of a conventional antenna device.

[0005] In FIG. 4, the antenna device 10 is connected to a tuner 20 by a two-wire cable 30.
The antenna device 10 selects an antenna element 11a for receiving a right-handed circularly polarized wave, an antenna element 11b for receiving a left-handed circularly polarized wave, antenna amplifiers 12a and 12b, and antenna elements 11a and 11b by a selection circuit S1. The antenna selection means 13 is provided.

The tuner 20 includes an RF signal amplifier 21 and a power supply 22 for supplying power to the antenna device 10. The two-wire cable 30 is connected to the antenna device 1
0 and the tuner 20 are connected, and the RF signal from the antenna device 10 is superimposed on the power supply voltage.

[0007] The operation of the antenna device configured as described above will be described with reference to FIG. FIG. 5 is a timing chart showing an example of voltage control of the power supply 22 for selecting an antenna element. In FIG. 5, "antenna selection" indicates a selection mode for selecting right-handed circular polarization and left-handed circular polarization of the antenna elements 11a and 11b, and a symbol "V1" indicates control of the power supply 22 when the antenna element is selected. 4 shows an example of a signal.

Now, a right-handed circularly polarized radio wave arrives from a satellite,
It is assumed that reception is performed by the antenna element 11a. The radio wave received by the antenna element 11a is transmitted to the antenna amplifier 12
Input to the selection circuit S1 via a. A power supply from a supply power supply 22 of the tuner 20 supplies a voltage necessary for the operation of the antenna amplifier 12a and the antenna selection means 13 via the two-wire cable 30.

As shown by a symbol V1 in FIG. 5, two voltages of 3V and 2V are controlled from a power supply 22 in order to switch the antenna elements 11a and 11b. The antenna selection unit 13 determines whether the threshold voltage is equal to or higher than 2.5 V. When it is determined that the voltage is less than 2.5 V, the output of the antenna amplifier 12a is output to the selection circuits S1,
A right-handed circularly polarized RF signal can be input to the amplifier 21 of the tuner 20 via the linear cable 30.

[0010]

However, in the above configuration, the supply power source 22 supplies the antenna amplifiers 12a and 12a.
Although the voltage supplied to b has a supply capability of 3 V, the upper limit value is 2 V due to the restriction of the selection voltage for left-hand circular polarization. Due to this limitation, there is a first problem that the antenna amplifier 12a deteriorates in securing the RF performance as compared with the performance at the supply voltage of 3V.

Further, in order to select an antenna, the supply voltage is changed around a threshold voltage of 2.5 V to select the antenna elements 11a and 11b. If the threshold voltage is detected under this condition, there is a second problem that a malfunction of erroneously switching the antenna element easily occurs due to the influence of the impulsive noise of the electrostatic noise.

In addition, in order to select two antenna elements, it is necessary to determine two types of voltage drop of the power supply 22, and the voltage margin for reliably operating the antenna selecting means 13 is reduced. There is a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an antenna device capable of operating any of the antenna amplifiers at the same voltage and capable of reliably and easily determining an antenna switching signal. The purpose is to provide.

[0014]

In order to solve the above-mentioned problems, the present invention takes the following measures.

According to a first aspect of the present invention, an active antenna including a plurality of antenna elements and an amplifier, and the plurality of antenna elements are operated at a predetermined voltage while the antenna elements are lower than the predetermined voltage. Antenna selection control means for performing selection control by voltage.

With this configuration, the antenna amplifier can be operated at the specified voltage, and erroneous selection of the antenna element due to electrostatic noise can be prevented.

According to a second aspect of the present invention, in the antenna device according to the first aspect, the antenna selection control means includes:
The antenna element is selected according to the voltage value of the control signal determined corresponding to each antenna element.

According to a third aspect of the present invention, in the antenna device according to the first aspect, the antenna selection control means includes:
The antenna element is selected based on the pulse width of the control signal determined corresponding to each antenna element.

With these configurations, the antenna amplifier can be operated at the specified voltage, and the range of the selection control signal can be widened. Therefore, the selection of the antenna element can be reliably performed with a margin for the voltage. It can be carried out.

According to a fourth aspect of the present invention, in the antenna device according to the second or third aspect, the antenna selection control means detects a down pulse of the operating voltage supplied to the antenna element, and then controls the control signal of the control signal. The antenna element is selected by detecting the voltage value or the pulse width.

With this configuration, the switching of the antenna element is performed when the power supply after the detection of the down pulse is in the specified state, and the timing for driving the active antenna is set to the specified voltage state. Can be increased.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An antenna device according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG.
1 is a block diagram of an antenna device according to one embodiment of the present invention. The same members as those of the conventional antenna device shown in FIG.

(Embodiment 1) In FIG. 1, an antenna device 10 is connected to a tuner 20 by a two-wire cable 30. The antenna device 10 includes an antenna element 11a that receives a right-handed circularly polarized electric wave, an antenna element 11b that receives a left-handed circularly polarized electric wave,
Antenna amplifiers 12a and 12b connected to 1a and 11b to amplify an output RF signal, and antenna elements 11a and 11b
Antenna selection means 13 for selecting the
And protection means 14 for preventing erroneous selection of antenna elements 11a and 11b.

The two antenna elements 11a and 11b and the antenna amplifiers 12a and 12b constitute an active antenna. The tuner 20 includes an amplifier 21 for demodulating an RF output and a power supply 22 supplied to the antenna device 10. Two-wire cable 30
Connects between the antenna device 10 and the tuner 20,
The power supplied via the two-wire cable 30 and the RF signal received by the antenna device 10 are superimposed.

Using a two-wire cable 30, power supplied to the antenna device 10 and R
By superimposing the F signal, a separate control cable is not required, the device configuration is simplified, and an increase in cost can be avoided.

The protection means 14 controls the selection operation of the selection circuit S1 by the antenna selection means 13. This control
A timing signal for a determination period that determines the timing of the determination of switching of the selection circuit S1 is output to the antenna selection means 13. The determination is made after detecting a down pulse of the power supply voltage supplied to the antenna device 10 and after a certain time from the edge thereof.

The operation of the antenna device configured as described above will be described with reference to FIG. FIG. 2 is a timing chart of antenna element selection applied to the first embodiment. In FIG. 2, “antenna selection” indicates a selection mode of left-hand circular polarization and right-hand polarization, and a symbol “V2” indicates The voltage of the power supply 22 that switches between left and right polarizations, the output signal of the protection unit 14, and the internal clock of the antenna selection unit 13 are shown.

The power supply 22 supplies a voltage necessary for the operation of the antenna amplifiers 12 a and 12 b, the antenna selection means 13 and the protection means 14 via the two-wire cable 30. In the same manner as in the conventional example, the arriving right-handed circularly-polarized radio wave is received by the antenna element 11a, and the antenna amplifier 1
The signal is input to the selection circuit S1 via 2a.

The power supply voltage supplied to the antenna device 10 is:
In order to guarantee the characteristics of the antenna amplifiers 12a and 12b,
Although the fixed value is 3 V, when the antenna elements 11a and 11b are switched, the voltage is controlled by two kinds of voltage values of the supply power supply 22 dropped.

In this control operation, as shown in FIG. 2, for example, in order to select the right-handed circularly polarized wave, the voltage drops from 3V to 2V for a certain period, and thereafter returns to the fixed value of 3V. To select left-handed circular polarization, the voltage drops from 3V to 1V for a certain period, and then returns to the fixed value of 3V.

When the right-handed circularly polarized antenna element 11a is selected, the protection means 14 sets the control voltage of the power supply 22 to 3V.
2 is detected, and after a certain period of time elapses, it is logically determined whether or not the threshold voltage is equal to or higher than 1.5 V within the determination period of the protection means 14 in FIG. The output of the protection means 14 has a threshold voltage of 1.5 V or more for right-handed circularly polarized waves, and has a logical value "H".

The antenna selection means 13 detects a down pulse having a threshold voltage of less than 2.5 V dropped from the power supply 22, and latches the logical value "H" of the output of the protection means 14 at the rise of the internal clock. , Selection circuit S
1 to select the output of the antenna amplifier 12b.

As a result of this switching, the antenna element 11a that has received the right-handed circularly polarized radio wave becomes an antenna amplifier 11a,
The signal is input to the amplifier 21 of the tuner 20 via the two-wire cable 30 via the selection circuit S1.

When receiving left-hand circularly polarized radio waves,
In FIG. 2, the protection means 1 is controlled by the control voltage of the power supply.
4 detects a down pulse that drops from 3V to 1V of the control voltage of the power supply 22, and after a certain period elapses, FIG.
The logic of the output of the protection means 14 is set to 1 V during the determination period.
The following logical decision is made.

Similarly, a down pulse falling below 2 V of the control voltage of the power supply 22 is detected, and the logical value “L” of the output of the protection means 14 is changed at the rise of the internal clock of the antenna selection means 13. Latch and select circuit S1
Can select the output of the antenna amplifier 12b.

According to the first embodiment, while the antenna amplifiers 12a and 12b are driven at 3V, the switching control voltages of the antenna elements are set at 1V and 2V, and a predetermined judgment period is provided. In addition, both antennas can be efficiently operated with a simple configuration, and erroneous selection of antenna elements due to electrostatic noise can be prevented.

(Embodiment 2) Next, an antenna device according to Embodiment 2 of the present invention will be described with reference to FIG. The configuration of the device is the same as that of the first embodiment. FIG.
FIG. 9 is a timing chart for selecting an antenna element applied to the second embodiment.

In the symbol "V3" in FIG. 3, the operating voltage of the antenna element is 3 V as in the first embodiment, but the voltage of the control signal for antenna switching is a constant voltage value. In the second embodiment, the voltage is set to 2V. This voltage drop period (pulse width) is made different between right-handed circular polarization and left-handed circular polarization. The right-handed circularly polarized wave is referred to as period a, and the left-handed circularly polarized wave is referred to as period b.

Under these conditions, the determination of right-handed circular polarization and left-handed circular polarization is made based on the difference between the time intervals of the periods a and b. For example, when right-handed circularly polarized light is selected, a period a (for example, period a> b) is detected, and a logical value “H” is set as an output signal of the protection unit 14 in a determination period. When the internal clock of the antenna selection means 13 rises, the protection means 1
Latching the "H" of the output signal of No. 4 and switching the selection circuit S1, the right-handed circularly polarized wave is selected.

Similarly, when selecting the left-handed circularly polarized wave, the period b (period b <period a) of the symbol "V3" is detected, and the logical value "L" is output from the protection means 14. At the rising edge of the internal clock of the antenna selecting means 13, "L" of the output signal of the protecting means 14 is latched, and the selecting circuit S1 is switched to select the left-handed circularly polarized wave.

According to the second embodiment, the voltage margin of the operating voltage of the antenna amplifier, the antenna selection means and the protection means can be increased, so that malfunction can be almost certainly avoided.

[0042]

As described above, according to the present invention, it is possible to obtain an antenna device which can operate any antenna amplifier at the same voltage and can easily and easily determine an antenna switching signal. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram of an antenna device according to an embodiment of the present invention.

FIG. 2 is a timing chart for selecting an antenna element applied to the first embodiment;

FIG. 3 is a timing chart for selecting an antenna element applied to the second embodiment;

FIG. 4 is a block diagram of a conventional antenna device.

FIG. 5 is a timing chart showing an example of voltage control of a power supply for selecting an antenna element in a conventional mode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Antenna device 11a, 11b Antenna element 12a, 12b Antenna amplifier 13 Antenna selection means 14 Protection means 21 RF amplifier of tuner 22 Supply power supply 30 Two-wire cable

Claims (4)

[Claims] 1. An active antenna comprising a plurality of antenna elements and an amplifier, and a power supply from a power supply via a two-wire cable to operate the plurality of antenna elements at a predetermined voltage while operating the antenna elements at the predetermined voltage. Antenna selection control means for performing selection control at a voltage lower than the voltage. 2. The antenna device according to claim 1, wherein the antenna selection control means selects the antenna element according to a voltage value of a control signal determined corresponding to each of the antenna elements. 3. The antenna device according to claim 1, wherein the antenna selection control means selects an antenna element based on a pulse width of a control signal determined corresponding to each antenna element. 4. The antenna selection control means selects an antenna element by detecting a voltage value or a pulse width of a control signal after detecting a down pulse of an operating voltage supplied to the antenna element. Claim 2
Or the antenna device according to claim 3.