JPH05152983A - Receiving equipment - Google Patents

Abstract

PURPOSE:To obviate unreceivability due to a fact that a direct wave and an indirect wave become opposite in phase at a receiving point by a multi-path phenomenon. CONSTITUTION:The equipment is provided with an AGC amplifying 3 for amplifying a signal received through antenna 1 to a prescribed level, and an antenna controller 4 for varying mechanically or electrically a position of the antenna 1, based on an AGC voltage in this AGC amplifier 3. By varying and controlling the antenna position so that a receiving level becomes maximum, based on the AGC voltage, a direct wave and an indirect wave become the same in phase at receiving point, unreceivability caused by multi-path phenomenon is obviated, and also, the maximum gain of reception can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver in line-of-sight communication and, more particularly, to a receiver which prevents reception failure due to a multipath phenomenon.

[0002]

2. Description of the Related Art In line-of-sight communication, when a multipath phenomenon represented by a two-wave model due to reflection at an interface occurs between a transmission point T and a reception point R as shown in FIG.
The direct wave of the passage r1 and the indirect wave of the passage r2 interfere with each other at the reception point R.

[0003]

The phase relationship between the direct wave and the indirect wave interfered at the receiving point R is determined by the transmitting point T and the receiving point R.
It is determined by the distance between the two and the state of the reflecting surface such as the interface. However, when the phase relationship of both waves is in opposite phase at the receiving point R, the signal disappears due to the interference of both waves, and the signal cannot be received at all. There is a problem that it may disappear. It is an object of the present invention to provide a receiving device that eliminates the inability to receive due to such a multipath phenomenon.

[0004]

The receiving apparatus of the present invention is configured so that the antenna controller controls the position of the antenna based on the AGC voltage of the AGC amplifier that amplifies the signal received through the antenna to a certain level. .

[0005]

By controlling the antenna position so that the reception level is maximized based on the AGC voltage, the reception failure due to the multipath phenomenon is eliminated.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. The received signal from the antenna 1 is frequency-converted by the frequency converter 2, further input to the AGC amplifier 3 and amplified so as to have a constant level, and fluctuations of the received signal due to the line are removed. The antenna 1 is constructed so that its position can be mechanically changed by a driving mechanism (not shown), and its position is controlled by an antenna controller 4. Then, the AGC voltage corresponding to the received signal level of the AGC amplifier 3 is input to the antenna controller 4,
The position of the antenna 1 is controlled to be changed according to the change of the AGC voltage.

Here, as shown in FIG. 2, when multipath represented by a two-wave model occurs between a transmission point T and a reception point (antenna position) R in line-of-sight communication,
The AGC generated corresponding to the received signal level of the AGC amplifier 3 so that the respective phases of the direct wave of the passage r1 and the indirect wave of the passage r2 do not become opposite phases at the reception point R, and preferably have the same phase. The position of the antenna 1 is mechanically controlled using the voltage. As a result, it is possible to prevent the signals at the reception point R from disappearing in opposite phases due to the multipath phenomenon, and to control the phases of both signals to be in phase so that the reception level becomes the maximum gain, and suitable reception is achieved. It will be possible.

Here, the position of the antenna 1 can be moved not only mechanically but also electrically by moving the center of the beam electrically using, for example, a phased array antenna.

[0009]

As described above, according to the present invention, since the position of the antenna is controlled based on the AGC voltage of the AGC amplifier, the phase relationship between the direct wave and the indirect wave in the multipath phenomenon is made in-phase, and the reception failure is prevented. There is an effect that the received signal can be maximized while being eliminated.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a main part of a receiving apparatus of the present invention.

FIG. 2 is a schematic diagram for explaining a multipath phenomenon.

[Explanation of symbols]

 1 antenna 2 frequency converter 3 AGC amplifier 4 antenna controller

Claims (1)

[Claims] 1. An AGC amplifier (automatic gain control amplifier) for amplifying a signal received through an antenna to a constant level.
And an antenna controller for controlling the position of the antenna by the AGC voltage of the AGC amplifier.