JPH0490624A - Interference compensating receiver - Google Patents

Abstract

PURPOSE:To simplify construction without necessitating the installation of the antenna device for interference wave reception by suppressing an interference signal interfering with the desired signal to be received and receiving only the desired signal. CONSTITUTION:A signal branched by a signal branching circuit 20 is passed through a transmission path with the length of approximately 1/2 of the difference between the electric length against the desired signal and the one against the interference signal in an interference signal suppress circuit 30, further, the amplitude and phase of the signal is controlled to obtain the amount of the control, the other signal is synthesized again, and the interference signal is suppressed. Therefore, only the desired signal can be received without affected by the influence of the interference signal. Thus, the communication quality can be maintained without affected by the influence of the interference wave even when the two antenna devices, which are the antenna device 10 for communication and the one for interference wave, are not utilized.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an interference compensated receiving device in wireless communication,
The present invention relates to an interference compensation receiving apparatus for a wireless transmission system that suppresses interference signals that interfere with a desired signal to be received and receives the desired signal.

[Conventional technology]

Radio wave interference is an important problem in wireless communications. Conventionally, techniques for suppressing such interference have been developed. Fourth
The figure shows an example of a conventional interference compensation device. Control method for interference compensation devices, generally called sidelobe cancellers (
For example, an interference compensation device according to Japanese Patent No. 1409006 is used.

In FIG. 4, reference numeral 21 denotes a communication antenna device, which causes interference signals to be mixed in with signals to be received. For this reason, an antenna device 22 is provided for receiving signals that cause interference.

23 is an amplitude and phase control circuit that controls and outputs the amplitude and phase of the interference wave received by the antenna device 22. 24 is a signal synthesis branch circuit, which after synthesizing two input signals,
This combined signal is branched into two systems and output. 25
is a receiver and receives the communication signal to be received.

The interference wave received by the antenna device 22 is transmitted to the antenna device 2.
] After being controlled by the amplitude/phase/amplitude circuit 23 to have the same amplitude and opposite phase as the interference wave mixed in, the signal synthesis branch circuit 24
It is combined with the received signal of the antenna device 21 to suppress interference waves. This combined signal is further branched into two systems by a signal combining branch circuit 24, and one is inputted to a receiver 25. The other signal is input to the amplitude and phase control circuit 23, and the residual interference wave included in the output signal from the signal synthesis branch circuit 24 is detected. Further, the amplitude and phase of the signal are compared with the interference wave signal received by the antenna device 22, and then, at the output of the signal synthesis branch circuit 24, the amplitude and phase control amounts necessary for suppressing the interference wave are determined. and controls the amplitude and phase of the interference wave signal received by the antenna device 22.

As a result, the interference waves in the received signal of the antenna device 21 are suppressed, and the desired communication signal is transmitted to the receiver 25 without interference.
and can be received.

[Invention or problem to be solved]

However, conventionally, an antenna device 22 for receiving interference waves is required in addition to the antenna device 21 for communication, and the installation cost becomes high.

Furthermore, when the interference waves are multiple reflected waves, the frequency characteristics of the interference waves input to both the communication antenna device 21 and the interference wave antenna device 22 are different, making it difficult to suppress the interference waves. There was a problem.

The present invention was made in view of the above points, and it is possible to maintain communication quality without being affected by interference waves without using two antenna devices: a communication antenna device and an interference wave antenna device. An object of the present invention is to provide a compensated receiving device.

[Means to solve the problem]

FIG. 1 is a diagram explaining the principle of the present invention.

A signal branching circuit 20 that branches a received signal containing a desired signal received by the antenna device 10 and an interference signal that interferes with the desired signal into two systems and outputs the branched signal, and an output from one output terminal of the signal branching circuit 20. The signal is passed through a transmission line having a length such that the difference between the electrical length for the desired signal and the electrical length for the interference signal is approximately an odd multiple of 1/2 of the wavelength, and the signal that has passed through the transmission line or the signal branching circuit 20 After controlling the amplitude and phase of one of the signals from the other output terminal of the signal branching circuit 20 , after passing through the transmission path, the signal whose amplitude and phase has been controlled and the signal from the other output terminal of the signal branch circuit 20 or an interference signal suppression circuit 30 that suppresses the interference signal by combining the signal that has passed through the transmission path and a signal whose amplitude and phase have been controlled from the other output signal of the signal branching circuit 20; It has a receiver 40 into which the signal extracted from the suppression circuit 30 is input, and receives only the desired signal.

[Effect]

In the present invention, one of the signals branched by the signal branching circuit 20 is passed through the interference signal suppression circuit 30 through a transmission path having a length such that the difference between the electrical length for the desired signal and the electrical length for the interference signal is approximately 1/2 wavelength. The desired signal can be received without being affected by the interference signal by controlling the amplitude and phase of the signal, obtaining the control amount, and combining the other signal again to suppress the interference signal. .

〔Example〕

FIG. 2 shows a configuration diagram of an embodiment of the present invention. In this figure, the same parts as in FIG. 1 are given the same reference numerals, and their explanations will be omitted.

30 is an interference signal suppression circuit, and a signal synthesis branch circuit 31
a transmission line 32 for creating a path difference between the desired signal and the interference signal branched by the signal, and an amplitude phase control circuit 3
Consists of 3.

Here, when the frequency of the interference wave is f and the frequency difference between the adjacent desired wave and the desired wave is Δf, the wavelengths λ and λ' of the interference wave and the desired wave in vacuum can be expressed by the following equations.

λ = c/f...
(1) λ'=c/(f+△f) ...(
2) However, C is the radio wave propagation speed in vacuum.

Let the length of the transmission line 32 be L, and the interference wave of wavelength λ and the wavelength λ'
Assuming that a difference of 0.5 wavelength occurs between the desired wave and the transmission line 32, (L/λ')-(L/λ)=0.5 (3
)L = c/(2Δf)...(
4). However, the above equation applies to the case of propagation in a vacuum, and the speed varies depending on the propagating medium, so it is necessary to take this into consideration when determining the length of the transmission path 32.

Therefore, the signal passing through the transmission line 32 whose length is set approximately as shown in the above equation and the other signal output from the signal branching circuit 20 that does not pass through the transmission line 32 are the interference waves. Or, when one of the desired waves is out of phase, the other is approximately in phase.

Therefore, in this embodiment, the signal received by the antenna device IO is branched into two systems by the signal branching circuit 20, one branched signal passes through the transmission path 32, and the other branched signal is transmitted by the signal branching circuit 20. After the amplitude and phase are controlled by the amplitude and phase control circuit 33 so that the interference wave has the same amplitude and opposite phase as the interference wave in the output signal, the signal synthesis branch circuit 31 controls the signal branch circuit 2.
By being combined with the other output signal from 0,
Interference waves are suppressed, and desired waves approximately in phase are synthesized and extracted.

The signal synthesized by the signal synthesis branch circuit 31 is further branched into two systems. One of the branched signals is input to the receiver 40.

The amplitude phase control circuit 33, which is supplied with the other signal branched by the signal synthesis branch circuit 31 as an input signal, detects the residual part of the interference wave included in the output signal of the signal synthesis branch circuit 31, and The amplitude and phase are compared with the output signal from the antenna device IO to obtain amplitude and phase control amounts necessary for suppressing interference waves at the output of the signal synthesis branch circuit 31. Control the phase.

As a result, any interference waves in the signal input to the receiver 40 are suppressed, making it possible to receive only the desired wave without interference from the interference waves.

The operation of the amplitude and phase control circuit 33 may be performed using the same automatic control method as the amplitude and phase control circuit 23 of the conventional interference compensation receiver shown in FIG. 4. However, for a simpler configuration, the phase shifter, attenuator (amplifier), etc. may be manually set.

In addition, when receiving signals with multiple frequencies, if the phase shifter, attenuator (or amplifier), etc. have large frequency characteristics, an attenuator (or amplifier) corresponding to the frequency of each interference wave and Prepare a phase shifter, and use an attenuator with the attenuation amount and phase shift amount set for each frequency change or frequency
Alternatively, the set values of the attenuator (or amplifier) and phase shifter may be automatically switched each time the frequency is changed.

FIG. 3 shows a block diagram of another embodiment of the present invention.

In the figure, 34 is a transmission line, which is the same as the transmission line 32 in FIG. 2, 35 is a signal synthesis branch circuit, which is similar to the signal synthesis branch circuit 31 in FIG. 2, and 36 is an amplitude phase control circuit. This circuit is similar to the amplitude phase control circuit 33 in FIG. 2, and performs the same operation. In the figure, the transmission line 34
The interference signal is suppressed by combining the amplitude and phase of the signal passed through the signal branching circuit 20 and the other output signal of the signal branching circuit 20 with the signal controlled by the amplitude phase control circuit 36 and the signal synthesis branching circuit 35.

Note that the lengths of the transmission lines 32 and 34 may be such that the difference between the interference wave and the desired wave is an odd number multiple of 1/2 wavelength.

〔Effect of the invention〕

As described above, according to the present invention, it is not necessary to install an antenna device for receiving interference waves, and the structure is simple and inexpensive.

In addition, unlike the case where signals with different frequency characteristics input to two antenna devices are combined for interference waves with complex frequency characteristics such as multiple reflected waves, interference waves input to one antenna device can be combined into two. After branching, one of the signals is combined with the opposite phase, so it is possible to suppress interference waves, and it is possible to receive communication signals without interference.

Branch circuit, 32.34...Transmission line, 33.36...
Amplitude phase control circuit, 40...receiver.

Claims (1)

[Claims] A signal branching circuit that branches a received signal containing a desired signal received by an antenna device and an interference signal that interferes with the desired signal into two systems and outputs the branched signal, and one of the signal branching circuits. The output signal from the output terminal is passed through a transmission line having a length such that the difference between the electrical length for the desired signal and the electrical length for the interference signal is a wavelength that is approximately an odd multiple of 1/2, and further passed through the transmission line. After controlling the amplitude and phase of either the signal or the signal from the other output terminal of the signal branching circuit, the signal whose amplitude and phase has been controlled and the signal branching after passing through the transmission path. The interference signal is eliminated by combining the signal from the other output terminal of the circuit, or by combining the signal that has passed through the transmission line and the signal whose amplitude and phase are controlled from the other output signal of the signal branch circuit. 1. An interference compensation receiving device comprising: an interference signal suppression circuit for suppressing interference signals; and a receiver into which a signal extracted from the interference signal suppression circuit is input, and configured to receive only a desired signal.