JPH0318101A - Constant current circuit for polarizer - Google Patents

Abstract

PURPOSE:To prevent poor reception by connecting an NPN and a PNP transistors(TR) between a positive and a negative power sources in series, connecting one terminal of a waveguide coil to their mid-point and grounding the other terminal, and forming a constant current source capable of reversible switching. CONSTITUTION:The emitters of the PNP and NPN TRs 11 and 12 are connected in common, the positive and negative power sources are connected to the collectors, and the output of an operational amplifier 15 is connected to the bases through diodes 14 and 16 in forward and backward directions. One terminal of the waveguide coil 13 is connected to the common emitter connection point of the TRs 11 and 12 and the other terminal is grounded through a resistance 18. An amplifier 15 compares the reference voltage of a variable voltage source 17 with a voltage developed across the resistance 18 and connects the positive or negative power source to supply a positive or negative constant current to the coil 13. Consequently, poor reception for a specific frequency band owing to residual magnetism is prevented when cross polarization is identified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to cross-polarized wireless communication, in which vertically polarized waves, horizontally polarized waves, or right-handed polarized waves are used. This relates to a circuit that supplies constant currents in opposite directions, positive and negative, to the waveguide coil of a polarizer, which is a receiving device for identifying left-handed circularly polarized waves. [Prior Art] In wireless communication systems, a cross-polarization system is adopted in order to expand communication capacity and avoid interference between wireless channels. In other words, in the frequency band above the microwave band,
By simultaneously using two orthogonal polarizations (right-handed polarization in circularly polarized waves and left-handed polarized waves or vertical and horizontal polarized waves in linearly polarized waves), the communication capacity is increased by 1, and the communication capacity is increased by 1. Interference with the system is often avoided. Therefore, on the receiving side,
It is necessary to distinguish between two orthogonal polarized waves. The ability to distinguish between two polarized waves is called cross-polarized@discrimination. A device that identifies such cross-polarized waves is called a polarizer. As shown in FIG. 4, the polarizer is incorporated into the primary radiator 2 installed at the focal point of the reflecting surface of the parabolic antenna l. One of the conventional polarizers is the fifth polarizer.
As shown in the figure, a waveguide coil 4 is installed around a probe 3 that receives radio waves, and a constant current is passed through the waveguide coil 4 to cause Faraday rotation in the received radio waves.
There is a polarizer 5 that performs cross-polarization discrimination.

Thus, the conventional polarizer 5 of this type performs cross-polarized wave discrimination by either passing a constant current through the waveguide coil 4 or not. In other words, for example, when a constant current is passed through the waveguide coil 4, vertically polarized waves are received, and when no current is passed through the waveguide coil 4, horizontally polarized waves are received and cross-polarized waves are received. Wave identification is performed. The reason why the current flowing through the four-wave tube coil 4 is kept constant is that a change in the current value changes the phase angle of the cross-polarized waves, making accurate polarization identification impossible.

[Problem to be solved by the invention]

In this way, in the polarizer 5 that performs cross-polarization discrimination by turning on and off the current to the waveguide coil 4,
There is a drawback that the phase angle of the cross-polarized waves changes due to the influence of the residual magnetic flux on the waveguide coil 4, resulting in poor reception. That is, for example, after passing a constant current to the waveguide coil 4 and receiving vertically polarized waves, the current to the waveguide coil 4 is cut off,
When horizontally polarized waves are received, residual magnetic flux is generated in the waveguide coil 4.

Therefore, the phase angle of the horizontally polarized wave deviates from the horizontal state. It goes without saying that if the phase angle of the horizontal B' 131 deviates, the receiving condition of the horizontally polarized wave at the probe 3 will be poor.

[Means for solving curricular problems]

The present invention has been made to improve and eliminate the above-mentioned conventional problems, and to enable cross-M polarization discrimination without causing a phase angle shift. ! The purpose is to provide a possible constant Ml/R circuit. Therefore, the means adopted by the present invention to solve the above problem is to supply positive and negative power to the waveguide coil of the polarizer.
A constant electric circuit for supplying Jj, with a positive power supply and a negative i\
! An NPN-connected transistor and a PNP
The connected transistors are connected in series, one end of the waveguide coil is connected to the intermediate connection point between the two types of transistors, and the other end of the waveguide coil is connected to ground. Diodes with opposite positive and negative directions are connected to the base side of the PNP transistor.

[For production]

In the present invention, an NPN transistor and a PNP transistor are connected between a positive power source and a negative power source, and the intermediate connection point of both transistors is connected to one end side of a waveguide coil. The other end of the line is connected to ground.
Then, diodes with opposite positive and negative directions are connected to the base sides of both transistors. As a result, when a positive power supply is supplied, a positive base voltage is applied to the base voltage of the PNP transistor, and tiP
NP} transistor turns on. Then, a constant positive current is supplied to the waveguide coil from the contrived lid side of the PNP transistor, making it possible to receive, for example, vertically polarized waves. Further, when a negative power source is supplied, a negative base voltage is applied to the base side of the NPN transistor, and the NPN transistor is turned on. Therefore, a negative constant electric current flows from the ground side through the waveguide coil to the NPN transistor side and collector side.

Therefore, a negative constant current flows through the waveguide coil 6, making it possible to receive, for example, horizontally polarized waves.

As described above, in the present invention, the constant current wires having opposite positive and negative directions are connected to the wave tube coil. When the direction of the constant current flowing through the waveguide coil is switched between positive and negative, the phase angle of the received radio waves will differ by 90 degrees due to the effect of one Farade rotation. Therefore, it is possible to receive vertically polarized waves and horizontally polarized waves respectively when a positive constant current is applied and when a negative constant current is applied, making it possible to perform cross-polarized wave identification. Is possible.

[Example] Below, the configuration of the present invention will be described based on an example shown in the drawings.

FIG. 1 is a constant current circuit diagram according to a first embodiment of the present invention. As shown in the figure, in this embodiment, PNP
The emitters of the transistor l1 and the NPN transistor 12 are connected to each other. And transistor l1
The collector side of the transistor 12 is connected to the positive power supply of +IOV, and the collector side of the transistor 12 is connected to the negative power supply of -10V. In addition, the intermediate connection point between the vines is connected to the waveguide coil 13.
It is connected to one end of the . The other end of the waveguide coil l3 is connected to ground. Further, the base side of the PNP transistor 11 is connected to the output side of the operational amplifier 15 via a positive diode 14. On the other hand, the base side of the NPN transistor l2 is connected to the output side of the operational amplifier l5 via a negative diode l6. In FIG. 1, 17 is a variable voltage source.
18 is a resistor. Assume that a positive power supply is now applied to the constant current circuit of the polarizer configured as described above.

In this case, a positive base voltage is applied from the operational amplifier l5 to the base side of the PNP transistor 11, and the transistor l1 is turned on. Therefore, transistor l
Current flows from the collector side of 1 to the ξ side. This current flows through the waveguide coil 13 to the ground side. That is, a positive constant current is applied to the waveguide coil 13, and the probe inside the waveguide can receive, for example, vertically polarized waves due to the Faraday rotation effect caused by the electromagnetic force of the waveguide coil 13. be. Next, assume that a negative power supply is applied. In this case, a negative base voltage is applied from the operational amplifier 15 to the base side of the NPN transistor l2. Therefore, this time, the NPN transistor 12 turns ON, and a closed circuit is formed in which a negative constant current flows from the ground side through the waveguide coil l3, through the output and collector of the transistor 12, and to the negative power supply side. ．． That is, a negative constant current is applied to the waveguide coil l3, and the probe inside the waveguide can receive, for example, horizontally polarized waves. As described above, in this embodiment, by passing constant currents in completely opposite directions, positive and negative, through the waveguide coil 13, cross-polarized waves are discriminated between vertically polarized waves and horizontally polarized waves. When a constant current in the completely opposite direction is passed through the waveguide coil 13, there is no problem that residual magnetic flux is generated in the waveguide coil 13.
Therefore, when cross-polarized waves are distinguished, there is no possibility of poor reception in specific frequency bands. FIG. 2 is a drawing showing a constant current circuit according to a second embodiment of the present invention. In this embodiment, the terminal 19. which is connected to both ends of the waveguide coil 13 of the embodiment shown in FIG.
iy1 if 20 is short-circuited or accidentally connected to ground? As a second protection function, transistor 21.
22 and resistors 23 to 27 are provided. The basic operation is the same as in the previous embodiment, so the explanation here will be omitted. FIG. 3 also shows that the base voltage supply circuit for supplying the base voltages of the PNP transistor l1 and the NPN transistor 12 to the operational amplifier 28.
This figure shows a third embodiment of the present invention in which the structure is formed using No. 29. The circuit of this embodiment has a variable voltage source 17
This circuit is connected to a computer because it can be controlled using only positive voltage. The other structure, functions, and effects are the same as those of the first and second embodiments described above, and their explanations will be omitted here. [Effects of the Invention] As explained above, in the present invention, a PNI' transistor and an NPN transistor are arranged in series and connected between positive and negative power supplies, and a waveguide coil is connected between the emitters of both transistors. One end of the waveguide coil is connected to the waveguide coil, and the other end of the waveguide coil is connected to ground.

Then, positive and negative constant currents are applied to the waveguide coil. In this way, when the direction of the constant current flowing through the waveguide coil is switched between positive and negative, the phase angle of the received radio wave will differ by 90 degrees due to the effect of one Farade rotation, and will differ from when a positive constant current is passed. , it is possible to receive vertically polarized waves and horizontally polarized waves, respectively, when a negative constant current is applied. In other words, it is possible to perform cross-polarization identification. Moreover, since either positive or negative current is always flowing to the waveguide coil, there is no possibility of residual magnetic east occurring, shifting the phase angle of polarized waves, and causing poor reception, as in the conventional case. do not have.

[Brief explanation of the drawing]

1 to 3 are drawings showing constant current circuits of polarizers according to first to third embodiments of the present invention, respectively, FIG. 4 is a side view showing a general parabolic antenna, and FIG. 5 is a partial longitudinal sectional view of a conventional polarizer. 5...Polarizer 1l...PNP Transistor 12...NPN }Transistor l3...Waveguide coil 14. 16...diode

Claims (1)

[Claims] 1. This is a constant current circuit for supplying positive and negative power to the waveguide coil of a polarizer, in which an NPN-connected transistor and a PNP-connected transistor are connected in series between the positive power source and the negative power source. , one end of the waveguide coil is connected to the intermediate connection point between the two types of transistors, and the other end of the waveguide coil is connected to ground, and the NP
A constant current circuit of a polarizer characterized in that diodes with opposite positive and negative directions are connected to the base sides of an N transistor and a PNP transistor, respectively.