JP3120610B2 - Polarization transmission system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarization transmission system and, more particularly, to a polarization transmission system that additionally operates a cross polarization interference compensator when changing from a single polarization transmission system to a dual polarization transmission system. .

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional dual-polarization transmission system includes a radio frequency reception signal 1 which is a digital modulation signal transmitted by two orthogonal polarizations having the same frequency.
01 and 201 are converted into reception signals 102 and 202 in the intermediate frequency band by the receivers 10 and 20. Received signals 102 and 202 in the intermediate frequency band are input to demodulators 11 and 21 and cross polarization interference compensators 18A and 28A. Demodulators 11 and 12
In 1, the demodulated received signals 102 and 202 are digitally converted and output as baseband digital signals 103 and 203. The cross polarization interference compensators 18A and 28A are composed of cross polarization demodulators 14 and 24, transversal filters 15 and 25 as cross polarization interference compensation waveform equalizers, and control signal generators 16 and 26. . Here, the cross polarization interference compensators 18A and 28A respectively receive the reception signals 102 and 202 from the other polarizations and receive their own coupler 1
Compensation signals for removing interference from the other polarizations are supplied to 2,22. Received signals 102 and 202 are demodulators 1 for cross polarization.
At 4 and 24, baseband digital signals 107 and 207 are output after being demodulated by the reproduced carrier signals 112 and 212. Transversal filters 15 and 25 receive baseband digital signals 107 and 207, respectively, and compensate signals 109 and 209 corresponding to the amount of cross polarization interference.
Is output. Switches 17A and 27A receive compensation signals 109 and 209 and a predetermined level "0", respectively, select one of them by a selection signal, and supply output signals 110 and 210 to couplers 12 and 22. . Baseband digital signals 103 and 203 are combined with switch outputs 110 and 210 by combiners 12 and 22, respectively, to compensate for cross-polarization interference components. The combiner output signals 104 and 204 are discriminated by the discriminators 13 and 23 into main signals 105 and 205 to be sent to subsequent signal processing units and error signals 106 and 206 indicating residual error components after cross polarization interference compensation. You. Control signal generators 16 and 26 provide error signals 106 and 206 and baseband digital signal 10 respectively.
7, 207 and the transversal filter 1
The tap weight control signals 108 and 208 are output to 5, 25. Normally, the received signal 1
In many cases, 01 and 201 include cross polarization interference components. Therefore, compensation signals 109 and 20 corresponding to the amount of interference
9 are coupled to the baseband digital signals 103,203.

When the transmission capacity is small, a transmission system using only one polarization may be used. This system includes a receiver 10, a demodulator 11, a combiner 12, a discriminator 13, and a switch 17A. At this time, since the cross-polarization interference compensation signal 109 which is one input of the switch 17A is not input, the switch 17A is manually switched so that the output of the switch 17A is not predetermined so that the output of the switch 17A is not unstable. Is set to output a fixed level "0" signal. Therefore, coupler 1
In the output of No. 2, the input baseband digital signal 103 is output as it is as an equal level digital signal 104 without applying an undefined level signal.

In order to change to a dual-polarization transmission system in response to an increase in transmission capacity, a receiver 20 and a demodulator 2
1. The coupler 22 and the discriminator 23 are added. Further, cross polarization interference compensators 18A and 28 are provided to compensate for cross polarization interference.
A is implemented. In this case, the switches 17A, 27A
Are manually switched and the cross-polarization compensation signals 109 and 209
Is output. In the couplers 12 and 22, the baseband digital signals 103 and 203 and the cross polarization compensation signals 109 and 2,
09 are combined to compensate for cross-polarized interference components.

[0005]

In the above-mentioned conventional polarization transmission system, a switching device is required along with mounting of a cross-polarization interference compensator which is necessary when changing from a single polarization to a dual polarization transmission system. Since it is necessary to switch manually, there is a disadvantage that the number of work steps increases and there is a possibility of erroneous operation.

[0006]

SUMMARY OF THE INVENTION A polarization transmission system according to the present invention is a cross-polarization system for compensating for interference from other polarizations when operating by changing from a single polarization transmission system to a dual polarization transmission system. In a polarization transmission system having an interference compensator and a coupler for coupling the compensation signal to a main signal, a fixed-level signal is supplied to the coupler in the case of the single polarization transmission system, In the case of a transmission system, a switch for automatically switching by a control signal from the outside so as to supply the compensation signal to the coupler, and a control signal for controlling the switch in the cross polarization interference compensator are generated. A control signal generator.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a circuit diagram of switches 17 and 27 which are main parts of the present embodiment. 1, the same reference numerals as those in the conventional example of FIG. 3 have the same configuration and function. That is, in the present embodiment, switches 1 and 2 that perform an automatic switching operation by an external signal described later, and a control signal generator that outputs a control voltage of switches 1 and 2 to cross polarization interference compensators 18 and 28. 3 and 4 are provided.

Next, the operation of this embodiment will be described. As described in the conventional example, when the transmission capacity is small, the cross polarization interference compensators 18 and 2 are operated in the single polarization transmission system.
8 is unnecessary. Therefore, for example, the switch 1 is controlled so as to select the fixed level "0" signal.

Next, when the transmission capacity is increased and the system is operated in a dual polarization transmission system, cross polarization interference compensators 18 and 28 are mounted and compensation signals 109 and 209 for compensating for interference from other polarizations with each other. Is output. At this time, the switches 1 and 2 perform automatic switching so as to transmit the compensation signals 109 and 209 to the couplers 12 and 22. This automatic switching will be described later in detail with reference to FIG.
Is mounted, the control signal generators 3 and 4 output the "H" level of the control voltage to switch the switches 1 and 2.

Next, the configuration and operation of the switching units 1 and 2 are shown in FIG.
This will be described with reference to FIG. The switch shown in FIG. 2 receives a signal of a predetermined fixed level “0” and a cross polarization interference compensation signal 109, and performs switching automatically with a control signal 111. A control circuit 19A holds a predetermined voltage between one end of the resistor 5 and ground when input, and is grounded via the resistor 5 when there is no control signal 111.

Next, the operation will be described. When the switching control signal 111 is not input to the switching unit main body 19, the control circuit 19A outputs a ground level signal to the switching unit main body 19 as a control signal via the resistor 5. When the level of the switching control signal is a signal of "L" (ground level), a signal of a predetermined fixed level "0" is automatically selected, and the level of the switching control signal 111 from the control signal generator 3 is changed. If the signal is “H”, the cross polarization interference compensation signal 109 is automatically selected. That is, the switch S1 is selected and output as the switch output 110 respectively. If the transmission capacity is small as described above, a transmission system using only one of the polarizations may be used. This system includes a receiver 10, a demodulator 11, a combiner 12, a discriminator 13, and a switch 17. Since this system does not include a cross polarization interference compensator, the control signal generator 3 switches to the switch 1 to switch the control signal 11.
1 is not input and the control circuit 19A outputs a signal of level "L" (ground level) as a switching control signal. That is, by selecting the switch S2, a signal of a predetermined fixed level "0" is automatically selected so that the output of the switch 1 does not become unstable, and is output to the coupler 12 as the switch output 110. Therefore, the input baseband digital signal 103 is output as it is without applying an undefined level signal to the output of the coupler 12.

[0012]

As described above, the present invention provides a switch for detecting whether or not a cross polarization interference compensator is mounted and automatically outputting a cross polarization interference compensation signal or a predetermined fixed level. With the provision, there is no need to manually operate the switching device to perform the switching, which has the effect of reducing work steps and erroneous operations.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a block diagram of a switching device as a main part of the embodiment.

FIG. 3 is a block diagram of a conventional example.

[Explanation of symbols]

 1,2,17,27 switch 3,4 control signal generator 5 resistor 10,20 receiver 11,21 demodulator 12,22 coupler 13,23 discriminator 14,24 cross polarization demodulator 15,25 Transversal filter 16, 26 Control signal generator 18, 28, 18A, 28A Cross polarization interference compensator 19 Switching unit body 19A Control circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04B 1/10-1/14 H04B 7/005

Claims (2)

(57) [Claims] 1. A cross polarization interference compensator for compensating for interference from other polarizations when operating after changing from a single polarization transmission system to a dual polarization transmission system, and using the compensation signal as a main signal. In the case of the single-polarization transmission system, a fixed-level signal is supplied to the coupler, and in the case of the dual-polarization transmission system, the compensation signal is supplied to the coupler. And a control signal generator for generating a control signal for controlling the switch in the cross-polarization interference compensator. Polarization transmission system. 2. A switching section main body, wherein the switching section selectively switches between the compensation signal and the fixed level, and a ground signal via a resistor when the switching section main body selects a fixed level. 2. The polarization transmission system according to claim 1, further comprising: a control circuit that supplies a control signal from the control signal generator to the switching unit main body when the compensation signal is selected for the main unit.