JPH04115636A - Receiver - Google Patents

Abstract

PURPOSE:To automatically deal with the polarizers of various kinds of systems by detecting the impedance of a part outside (polarizer side) the common terminal connected to the polarizers of various kinds of the systems, and switching connection between the terminal and each polarizer drive circuit according to a detected result. CONSTITUTION:Three terminals 10 (T1 to T3) for connecting the polarizers of various kinds of the systems, an impedance deciding unit 12 connected separately to each terminal T1 to T3, and a connection switching unit 14 to switch the connection between each terminal T1 to T3 and each drive-control unit 16, 18, 20 are provided. Then, the impedance deciding unit 12 discriminates the kind of the connected polarizer by deciding the impedance with each terminal T1 to T3 of the polarizer connection terminal 10, and connects automatically the drive.control unit to meet that polarizer. Thus, the polarizers of various kinds of the systems can be automatically dealt with.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates primarily to a receiver for receiving radio waves transmitted to the ground from broadcasting satellites and communication satellites.

When receiving satellite broadcasting, as shown in Figure 4, satellite 3
The radio waves transmitted from 0 are focused by a reflecting mirror 32 of a receiving antenna on the ground onto a horn 34 placed at its focal point, and converted into an electrical signal by a converter (LNB) 38. This high frequency signal is converted into a primary intermediate frequency signal by the converter 38 and then sent to the receiver 40, where the video and audio signals are extracted and output on the TV screen 42.

In order to effectively utilize radio wave resources, the radio waves transmitted from broadcasting satellites and communication satellites are divided into right-handed/left-handed circularly polarized waves, or vertical/horizontal linearly polarized waves depending on the country or purpose. There is. However, since the converter 38 can normally convert polarized waves in only one direction, it is necessary to rotate either the vertical or horizontal polarized waves in a direction in which the converter 38 can convert the polarized waves. Additionally, in the case of circularly polarized waves, they are first converted to linearly polarized waves using a dielectric plate, etc., but even in this case, the direction of the converted linearly polarized waves differs by 90° between right-hand rotation and left-hand rotation. Therefore, rotation of the linearly polarized wave is required for either one. Therefore, when trying to receive various satellite broadcast waves, it is necessary to use a device (polarizer or polar rotor) that can appropriately switch the direction of linearly polarized waves.
6 is required.

As such a polarizer 36, the following three types of systems are currently used.

■ Deflection plate rotation method By rotating the deflection plate using a pulse motor or the like and switching its inclination between Oo and 90'', the vertical/horizontal polarization is kept in a constant direction (Figure 2 (a)).

■ 2-converter system (OMT + 2LNB) A cavity resonator (ortho mode transducer = OMT) with an intake port corresponding to each vertical/horizontal linearly polarized wave and a dedicated converter (LNB) unit for each polarized wave in each direction. Prepare,
By appropriately switching between them, one of the linearly polarized waves is received (FIG. 2(b)).

■ Method for switching magnetic field direction around ferrite A coil is wound around the ferrite, and by changing the direction of the current flowing through the coil, the direction of the magnetic field is changed and the angle of polarization rotation by the ferrite is switched (Figure 2 (C)).

As shown in FIG. 4, the polarizer 36 is fixed to the antenna side, and since the antenna is usually not equipped with a power source, the polarizer 36 is controlled and driven from the receiver 40 side. There is a need to do.

However, as mentioned above, there are various types of polarizers, so the receiver side has been provided with connection terminals for each type so that it can support any type. For this reason,
In conventional receivers, there are space issues due to the large number of connection terminals for polarizers, and each time a different type of polarizer is connected to the corresponding terminal, the drive/control circuit inside the receiver side must be switched. There was a problem with the troublesome operation.

An object of the present invention is to solve such problems and provide a receiver that can automatically adapt to various types of polarizers.

In order to achieve the above object, in the present invention, a polarizer drive control circuit for switching the polarization direction of a linearly polarized radio wave is commonly connected to the polarizers of various types in a receiver equipped with each type of polarizer. A means for detecting impedance on the external side (on the polarizer side) from the terminal, and a switching means for switching the connection between the terminal and each polarizer drive circuit based on the impedance detection result. Features.

The number of drive terminals/control terminals and the internal impedance of the terminals differ depending on the type of polarizer. Therefore, the connection method for connecting polarizers of each type to the common terminal is determined, and after connecting the polarizer of either type to the common terminal according to the determined method,
By detecting the impedance outside the common terminal (on the polarizer side), it is possible to know what type of polarizer the polarizer is. Thereafter, by using the switching means to connect each terminal of the drive circuit corresponding to the detected method to the corresponding terminal of the common terminal, the polarizer connected to the receiver can be correctly driven and controlled.

Certain JL Example - Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the receiver according to this embodiment is equipped with internal drive/control units 16, 18, and 20 for each polarizer so that it can support any of the above three types of polarizers. There is. Furthermore, there are three terminals 10 (Tl, T2, T3) for connecting various types of polarizers.
, each terminal Tl, T2. Impedance determination unit 12 individually connected to T3, and each terminal Tl, T2
．． It is equipped with a connection switching unit 14 that switches the connection between T3 and each drive/control unit 16, 18, 20, and automatically switches the three types of drive/control units 16, 18, 20 according to the connected polarizer. It is designed to be switched.

The impedance determination unit 12 is constituted by a microcomputer, and performs the automatic switching described above by performing processing as shown in FIG. 3 in accordance with a program stored in advance in an internal ROM.

Before explaining the automatic switching process, let's take a look at Figures 2 (a) and (b).
) and (c), each polarizer 15.17.19 and its drive and control unit 16.18.20 will be explained. FIG. 2A shows a polarizer 15 and its drive/control unit (pulse motor drive unit) 16 using the deflection plate rotation method described above. The pulse motor drive unit 16 connects the pulse motor 22 of the polarizer 15 to the terminal ■
5■Power for driving is supplied from terminal 5, and pulses for rotation angle control are sent from terminal 5. ■ is a common ground wire.

The figure (b) shows the polarizer 17 and its control unit (SW voltage switching unit) 18 using the above two-converter system.
It is. The SW voltage switching unit 18 switches the voltage between the terminals ■ and ■ to either 12V or Ov depending on whether vertical or horizontal linearly polarized waves are to be received. In the polarizer 17, the selector switch 24 is set to the corresponding converter (LNBI or LNBI) depending on the voltage between the terminals 00.
NB2) and outputs only the output from that converter to the receiver 40.

FIG. 2C shows a polarizer 19 and its drive/control unit (forward/reverse current drive unit) 20 using the above-mentioned ferrite peripheral magnetic field direction switching method. Forward/reverse current drive unit 2
From 0, the current from the constant current generator 26 is applied to the coil of the polarizer 19 from the terminals ■ and ■ to generate a magnetic field around the ferrite rod, but the direction of this coil current can be reversed by the changeover switch 28. As a result, the direction of rotation of linearly polarized waves by the ferrite rod is reversed, and linearly polarized waves in the desired direction can be obtained.

When connecting these polarizers 15, 17, and 19 to the terminal 10 of the receiver 40, connect the terminals ■ and ■ of each polarizer.

■ (although there are cases where there is no ■ or ■) are Tl and T, respectively.
2゜Connect to T3.

Next, the automatic switching process performed by the microcomputer of the impedance determination unit 12 will be explained with reference to the flowchart of FIG. First, the impedance Z between terminals T1 and T2
12, it is determined in step #l whether the value z12 is infinite (or whether it is greater than a predetermined very large value) (step #12).

z12: In the case of (1), as shown in Figure 2 (C), there is only a case where a polarizer of the ferrite peripheral magnetic field direction switching method that does not use the terminal (TI) is connected, so it is necessary to correspond to it. The terminals (2) and (2) of the forward/reverse current drive unit 20 are connected to the polarizer connection terminal T2. A switching signal is output to the connection switching unit 14 so as to connect to T3 (step #18). 71 at step #12
If it is determined that 2≠(1), the process advances to step #14 and the impedance Z23 between the terminals T2 and T3 is then measured. In step #16, it is checked whether or not this value Z23 is infinite. If z23=ω, in step #20, the terminal ■ of the SW voltage switching unit 18 is
, ■ is sent to the connection switching unit 14 so as to connect the terminals Tl and T2 of the polarizer connection terminal 10, respectively. The impedance between TI and T2 is not infinite,
However, the impedance between T2 and T3 becomes infinite only when a two-block polarizer 18 that does not use the terminal (T3) is connected, as shown in FIG. 2(b).

If it is determined in step #16 that Z23≠■, the process advances to step #22, and the terminals ■ and ■ of the pulse motor drive unit 16 are connected to Tl of the polarizer connection terminal 10, respectively.
, T2. Issue a switching signal to connect to T3.

As described above, the impedance determination unit 12 evaluates each terminal TI, T2 . By measuring the impedance between T3, the type of polarizer connected is determined, and a drive/control unit corresponding to the polarizer is automatically connected.

In addition, in the above embodiment, the case where the above-mentioned three types of polarizers are used is explained as an example, but even when using other types, the impedance between the terminals of each polarizer can be measured more accurately, By making detailed judgments, it is possible to distinguish between them, and automatic switching as in this embodiment can be performed. Furthermore, it goes without saying that the receiver is not limited to one that receives satellite broadcasting and satellite communication radio waves.

As described above, according to the present invention, even if the receiver is compatible with many types of polarizers, the number of terminals on the receiver side can be reduced, and space can be saved. In addition, as long as you connect the common terminal correctly, there is no need to manually switch the drive/control circuit inside the receiver for each polarizer method; the receiver will automatically switch.
Easy to operate.

FIG. 2 is an explanatory diagram showing how radio waves are received from the computer.

Claims (2)

[Claims] (1) In a receiver equipped with a drive control circuit for a polarizer that switches the polarization direction of linearly polarized radio waves for each type of polarizer, there is a terminal for common connection to the polarizers of various types, and a terminal external to the above terminal. A receiver comprising: means for detecting impedance; and switching means for switching the connection between the terminal and each polarizer drive control circuit based on the impedance detection result. (2) The receiver according to claim 1, wherein the various types of polarizers are a deflection plate rotation type, a two-converter type, and a ferrite peripheral magnetic field direction switching type, and three common terminals are provided.