JPH0478231A - Space diversity controller - Google Patents

Abstract

PURPOSE:To detect a small change in a synthesized output level without increasing the cost by selecting any of plural kinds of gains set by a gain variable means and operating the controller with a selected gain. CONSTITUTION:When a change in a synthesized output level per unit angle of a phase shifter 15 is smaller than a prescribed quantity set around a minimum resolution of an A/D converter 21, that is, around an optimum point, the gain of a variable attenuator 30 is decreased and an input level to the A/D converter 21 is doubled. Thus, a change in the synthesized output level per unit angle of the phase shifter 15 is doubled and reaches the minimum resolution of the A/D converter 21 or over. That is, the minimum resolution of the A/D converter 21 is increased equivalently. Thus, a control section 31 detects a small change around the optimum point and phase control of the phase shifter 15 is implemented accurately even around the optimum point.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention combines signals obtained from each of a main antenna and a sub-antenna arranged spatially apart from each other to generate a received signal. The present invention relates to a space diversity control device that controls a space diversity receiving device that obtains a space diversity receiving device.

(Prior Art) In wireless communication systems, synthetic space diversity is widely used as one of the methods to reduce the effects of fading.

FIG. 4 is a block diagram showing the conventional configuration of a space diversity receiving device and a space diversity control device that perform this combined space diversity.

In the figure, 1 is a space diversity receiving device, and 2 is a space diversity control device. The space diversity receiving device 1 has a main antenna 10 and a sub-antenna 11 that are arranged spatially apart, and uses the main antenna 10 and the sub-antenna 11, respectively, to transmit signals to a main receiver 12 and a sub-receiver 13. Reception occurs in parallel.

The signal obtained by the main receiver 12 is transmitted to the hybrid circuit 14
The signal is input to the sub-receiver 13, and is combined with a signal that is phase-shifted (phase-shift controlled) by the phase shifter 15. Thus, the combined output obtained by the hybrid circuit 14 is outputted as a received signal via the amplifier 16.

The space diversity control device 2 includes a level detection section 2
0, an A/D converter 21, and a control section 22. The level detection unit 20 generates a signal with a level corresponding to the level of the combined output output from the space diversity receiving device 1. The output signal of this level detection section 20 is A
After being digitized by the /D converter 21, a control section 22 having, for example, a microcomputer as a main control circuit
is input. Based on the input data, the control unit 22 controls the amount of phase shift of the phase shifter 15 so that the level of the combined output output from the space diversity receiving apparatus 1 is maximized.

By the way, in the case of the above configuration, the level change of the combined output with respect to the angle of the phase shifter 15 is small near the in-phase point which is the optimum point. In this way, when the level change becomes small near the in-phase point and becomes below the minimum resolution of the A/D converter 21, the control section 22 can capture the minute change, and therefore, can perform minute control near the in-phase point. do not have.

In order to solve this problem, it is possible to improve the minimum resolution of the A/D converter 21, but an A/D converter with such a high minimum resolution is expensive and the number of data bits increases. Therefore, the interface with the control unit 22 is also complicated and expensive.

(Problems to be Solved by the Invention) As described above, conventional methods have the disadvantage that minute changes in the combined output level near the in-phase point cannot be detected, and minute control cannot be performed near the in-phase point.

Furthermore, if an A/D converter with a high minimum resolution is used so as to be able to capture minute changes in the combined output level, the cost of the device will increase.

The present invention has been made in consideration of these circumstances, and its purpose is to provide a composite output level pace diversity control device with a very simple configuration and without increasing costs.

[Structure of the Invention] (Means for Solving the Problems) The present invention includes gain variable means such as a variable attenuator that passes the output signal of the level detection means at one of a plurality of types of gains, Based on the amount of change over time in the level of the output signal of the level detection means, one of the plurality of types of gains set in the gain variable means is selected, and the gain variable means is controlled with the selected gain. I got it working.

(Function) By taking such measures, the output signal of the level detection means is passed through the gain variable means with a gain based on the amount of change over time in the level of the output signal of the level detection means. Therefore, when the amount of change over time in the level of the output signal of the level detection means becomes small near the common-mode point, the gain of the gain variable means is changed (if the gain variable means performs attenuation, the gain is decreased or amplified). (increases if the level detecting means performs this), the amount of change over time in the level of the output signal of the level detecting means can be seen largely.

(Embodiment) Hereinafter, a space diversity control device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the space diversity control device. Note that the same parts as in FIG. 4 are given the same reference numerals, and detailed explanation thereof will be omitted.

In the figure, 3 is a space diversity control device. This space diversity control device 3 includes a variable attenuator 30 between the level detection section 20 and the A/D converter 21 in the conventional space diversity control device 2 shown in FIG.
has been established. Further, output data of the A/D converter 21 is input to the control section 31. This control section 31 controls the gain of the variable attenuator 30 in addition to a phase shift control means 31a that controls the phase shifter 15 in the same way as the control section 22 in the conventional space diversity control device 2 shown in FIG. It has gain selection means 31b for determining the gain.

FIG. 2 is a circuit diagram showing a specific configuration of the variable attenuator 30 in FIG. 1. In the figure, R1 is a resistor, and the output of the level detector 20 is input to one end of the resistor.

The other end is connected to the resistor R2 and the input end of the A/D converter 21.

And resistor R2 is grounded. In addition, resistor R1
, R2 are set to the same value. 30a is a switch, which is provided in parallel with the resistor R1.

This switch 30a is turned ON10FF in response to a switching signal from the control section 31.

Next, the operation of the space diversity control device 3 configured as described above will be explained according to the processing procedure of the control section 31. First, the control section 3 takes in the output data of the A/D converter 21 in step a, as shown in FIG. Then, in step b, the control unit 31 determines the control direction of the phase shifter 15 based on the data acquired in step a, and controls the phase shifter 15. The processing of steps a to step C is performed using the phase shift control means 31a.

After that, in step d, the control unit 3] controls the phase shifter 1.
Calculate the amount of change in the composite output level per unit angle of 5,
Subsequently, in step e, it is determined whether the amount of change calculated in step d is equal to or greater than a predetermined amount set to approximately the minimum resolution of the A/D converter 21.

If the amount of change is not greater than the predetermined amount, the control unit 3
1 moves the process from step e to step f, and in step f, the switch 30a of the variable attenuator 30 is turned on. After this, the control unit 31 repeats the processing from step a onward.

On the other hand, if the amount of change is not equal to or greater than the predetermined amount in step e, the control section 31 moves the process from step e to step g, and in step g, turns off the switch 30a of the variable attenuator 30.

After this, the control unit 31 repeats the processing from step a onwards. The processing from step d to step g is performed using the gain selection means 31b.

Thus, the switch 30a of the variable attenuator 30 is controlled to be 0N10FF as described above. The variable attenuator 30 operates as follows by the ON10FF control of the switch 30a by the control section 31.

That is, when the switch 30a is in the ON state, the resistor R1 is bypassed. Here, since the resistors R1 and R2 have the same resistance value, the potential at the connection point A between the resistors R1 and R2 is the same as that of the resistor R1 when the switch 30a is OFF.
It is twice as large when the switch 30a is in the ON state as compared to when the switch 30a is inserted.

Therefore, as mentioned above, when the amount of change in the combined output level per unit angle of the phase shifter 15 is smaller than the predetermined amount set to about the minimum resolution of the A/D converter 21, that is, when it is near the optimum point At this time, the gain of the variable attenuator 30 becomes low, and the input level to the A/D converter 21 doubles. Therefore, the amount of change in the combined output level per unit angle of the phase shifter 15 is also doubled, which is greater than the minimum resolution of the A/D converter 21. In other words, geometrically, the A/D converter 21
This means that the minimum resolution of Thereby, the control unit 31 can detect minute changes near the optimum point, and can more accurately control the phase shift of the phase shifter 15 even near the optimum point.

Also, at this time, the composite ratio no.j per unit angle of the phase shifter 15
Since the gain of the variable attenuator 30 is lowered only when the amount of change in level is smaller than a predetermined amount set to about the minimum resolution of the A/D converter 21, that is, when it is near the optimum point, The A/D converter 21 can be an inexpensive one with a low dynamic range.

Note that the present invention is not limited to the above embodiments. For example, the variable attenuator is not limited to the configuration described in the above embodiment. Further, in the above embodiment, a variable attenuator is used as the gain variable means, but a variable amplifier or the like may be used. In addition, various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] According to the present invention, the output signal of the level detection means is provided with gain variable means such as a variable attenuator for passing the output signal of the level detection means at one of a plurality of types of gains, and the output signal of the level detection means is Based on the amount of change in level over time, one of a plurality of types of gains set in the cane variable means is selected, and the gain variable means is operated at the selected cane. Therefore, the space diversity control device can capture minute changes in the composite output level with a very simple configuration without increasing costs, and can perform phase shift control with good precision even near the in-phase point.

[Brief explanation of drawings]

1 to 3 are diagrams for explaining a space diversity control device according to an embodiment of the present invention, in which FIG. 1 is a block diagram showing the configuration, and FIG. 2 is a variable attenuator 3 in FIG. 1.
0, FIG. 3 is a circuit diagram showing an example of the configuration of the controller 3 in FIG. 1.
FIG. 4 is a flowchart showing the processing procedure of No. 1, and is a diagram explaining the prior art. DESCRIPTION OF SYMBOLS 1... Space diversity receiver, 10... Main antenna, 11... Sub antenna, 12... Main receiver,
13... Sub receiver, 14... Hybrid circuit, 1
5... Phase shifter, 16... Amplifier, 3... Space diversity control device, 20... Level detection unit, 21
...A/D converter, 30...variable attenuator, 3]...
Control unit, 31a: phase shift control means, 31b: gain selection means. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] The combined output obtained by controlling the phase shift of the signals obtained by each of the main antenna and the sub antenna which are arranged spatially apart, and combining both signals in the same phase is the received signal. A space diversity control device for controlling a space diversity receiving device that controls a space diversity receiving device, the space diversity control device comprising: a level detection means for outputting a signal having a level corresponding to the level of the combined output; A space diversity control device comprising a phase shift control means for controlling the phase shift of a signal obtained by each of the sub-antennas, wherein the gain is variable for passing the output signal of the level detection means at one of a plurality of types of gains. and selecting one of the plurality of types of gains set in the gain variable means based on the amount of change over time in the level of the output signal of the level detection means, and adjusting the gain variable means to the gain variable means. A space diversity control device comprising gain selection means for operating with a selected gain.