JPS6041302A - Side lobe canceller device - Google Patents

Abstract

PURPOSE:To imporve the loss of a desired signal and to make a high-quality commnication possible by comparing desired signal components or SN ratios of the output terminal of a side lobe canceller and that of a synthesizer with each other and selecting the output terminal having a larger desired signal or a higher SN ratio with a selecting circuit. CONSTITUTION:A side lobe canceller device SLC is provided with a main antenna 11 and plural auxiliary antennas 12, and signals received by antennas 12 are weighted by a weighting circuit 13. Output signals of the circuit 13 are synthesized by a synthesizer 14, and the result is outputted to a synthesizer output terminal 18. A difference between this output signal and the signal received by the antenna 11 is operated by a difference circuit 15 and is outputted to a difference circuit output terminal 17. The output of this output terminal 17 is applied to a signal processing circuit 16 to determine weighting of the circuit 13. A selecting circuit 19 is proveded for output terminals 18 and 17 of the synthesizer 14 and the difference circuit 15, and the output terminal 18 or 17 having a larger desired signal or a higher SN ratio is selected by this circuit 19. Thus, the loss of the derired signal is improved to make a high-quality communication possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a sidelobe canceller device that automatically suppresses interference waves while adapting to the surrounding radio wave environment.

[Technical background of the invention and its problems] Sidelobe canceller device (hereinafter abbreviated as SLC)
is one of the adaptive antennas and has been mainly used in the radar field.

A conventional example of SLC is shown in FIG. In Figure 1, (1
) is the main antenna, (2) is multiple auxiliary antennas, (3
) is a weight circuit that weights the signal received by the auxiliary antenna (2), (4) is a combiner that combines the output signal of the weight circuit (3), and (5) is a combiner that combines the signal received by the main antenna (1). , a difference circuit that takes the difference from the output signal of the combiner (4), (6) is the output terminal of the SLC, (the power is the auxiliary antenna (2)
), the received signal is correlated with the signal at the output end (6) of the 8LC, and the weighting circuit (3) is weighted so as to remove strongly correlated signal components from the signal at the output end (6) of the 8LC. This is a signal processing circuit that makes decisions while learning.

There are two characteristics of the operation of 8LC as follows. First, the first WR,': So, the larger the power received by the auxiliary antenna (2), the faster the learning speed of weighting is.In other words, the signal with larger power is removed faster. be.゛The second feature is that the smaller the desired signal to interference ratio at the receiving end of the auxiliary antenna (2), the more improved the desired signal to interference ratio at the output end of the SLC (6). It is. Due to the above two characteristics,
You can see why SLC has been mainly applied to radar. In other words, in radar, the desired signal received by the auxiliary antenna has low power and is a pulse wave.

Because the learning speed of weighting for the desired signal is slow, SLC
The desired signal is not completely removed at the output end (6) of the auxiliary antenna (2), and the desired signal to interference ratio at the receiving end of the auxiliary antenna (2) is generally very small in a radar environment. From the above, SL
It can be seen that C is an effective means of suppressing interference waves in radar.

However, when SLC is applied to general communication systems,
It has the following serious drawbacks. In other words, in a communication system, there are cases where the desired signal exists continuously and the desired signal to interference wave power ratio at the receiving end button of the auxiliary antenna (2) is large, and the SLC operates to remove the desired signal. , the desired signal loss increases, causing a large loss to the communication system 1. OBJECT OF THE INVENTION] The present invention improves the drawbacks of the conventional device described above.
Its purpose is to improve the desired signal loss and
The objective is to provide SLC that improves the communication ratio and enables high-quality communication.

[Summary of the invention] That is, the desired signal component or SN ratio at the output end of the present invention ¥1sLc is compared with the output end of the synthesizer, the desired signal component or the output end with a large SN ratio is selected, and it is sent to the SLC.
The present invention is characterized in that it is equipped with a selection circuit for selecting the final output terminal.

[Effects of the Invention] The SLC of the present invention eliminates the drawbacks of the conventional example and improves the desired signal loss, for example, in a radio wave environment where the desired signal power is large and the interference wave power is very small. On the other hand, in an example of a radio wave environment where the interference wave power is large, the conventional SLC interference wave suppression performance can be exhibited, and the 8N ratio can be significantly improved.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 2 shows a schematic configuration diagram of an apparatus according to an embodiment of the present invention.

In Fig. 2, main antenna 01), auxiliary antenna Oa
, the weight circuit 0, the combiner I, and the difference circuit u signal processing circuit Oe are the same as those described in the conventional example. a7
) is the output terminal of the difference circuit, (country indicates the output terminal of the combiner Qa. 0 indicates the desired signal component or SN ratio of the difference circuit output terminal H and the combiner output terminal U is compared, and the desired signal component is determined. or 8
This is a selection circuit that selects an output end with a large N ratio. (stomach)
is the output terminal of the selection circuit 09, and indicates the final output terminal in the present invention.

The operating principle of the present invention will be explained below. First, assume a radio wave environment in which the desired signal is at a sufficiently large angle and the interference wave is very small. At this time, the weight output from the signal processing circuit αe is determined mostly by the desired signal component, and the weight output from the signal processing circuit αe is determined mainly by the desired signal component.
Both input terminals of I→ (main antenna ajj side and combiner output terminal (
The desired signal components on the IEO side have approximately the same amplitude and the same phase. Therefore, at the difference circuit output terminal 07), the desired signal component is suppressed and becomes 1. ball.

At this time, the 1 selection circuit al compares the desired signal component or SN ratio at the combiner output end and the difference circuit output end ON, and as described above, the desired signal component or SN ratio at the combiner output end is the difference circuit output. Since it is clearly larger than those at the end αη, the combiner output OgJ is selected as the selection circuit output ■.

On the other hand, in an example of a radio wave environment where the desired signal is very small and the interference wave is large, the weight is determined mostly by the interference wave component,
The interference wave components at both input ends of the difference circuit a9 have approximately the same amplitude and the same phase, and the interference wave components at the output end of the difference circuit a9 are suppressed. At this time, since the difference circuit output terminal Q7) has a larger desired signal component or S/N ratio than the synthesizer output terminal (181), the selection circuit section determines that the difference circuit output terminal Qη
Select as the selection circuit output. In this way, in a radio wave environment where the received power of the desired signal and interference wave changes in a complex manner, the difference circuit output terminal Q with a desired signal component or a large S/N ratio is
7) or the synthesizer output terminal θ, the desired signal loss can be improved and a great effect can be achieved.

The invention is not limited to the above embodiments. For example, the selection circuit may be a simple switch and a human may perform the comparison of desired signal components or signal-to-noise ratios. In other words, the present invention can be implemented with various modifications without departing from the gist thereof.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional sidelobe canceller device, and FIG. 2 is a diagram of an embodiment of the present invention. 1] Main antenna, 12... Auxiliary antenna, 13
...Wait circuit, 14...Synthesizer, 15...
Difference circuit, 16...Signal processing circuit, 17...Difference circuit output end, 18...Synthesizer output end, 19...Selection circuit, Addition...Selection circuit output end. Figure 1 Figure 2 f

Claims (1)

[Claims] a main antenna, a plurality of auxiliary antennas, and a weight circuit that weights signals received by the auxiliary antennas;
a combiner that combines the output signals of the weight circuit; a difference circuit that takes the difference between the signal received by the main antenna and the output signal of the combiner; the signal 5 received by the auxiliary antenna; A sidelobe canceller device comprising: a signal processing circuit that determines the weighting of the weight circuit so as to calculate the correlation with the output signal of the circuit, and remove highly correlated signal components from the output signal of the difference circuit. , comprising a selection circuit that compares the desired signal component or V/S/N ratio of the signal at the output end of the synthesizer and the output end of the difference circuit, and selects the output end with the larger desired signal component or S/N ratio. A sidelobe canceller device featuring: