JPH11136173A - Wireless relay amplifier - Google Patents

Abstract

(57) [Problem] To provide a radio relay capable of sufficiently securing the amount of cancellation of an interference signal due to a canceling signal even in the entire use frequency band even when the interval between a receiving antenna and a transmitting antenna is long. An amplification device is provided. SOLUTION: A distributor 4, a variable delay 6, a variable phase shifter 7, and a variable attenuator 8 are wrapped around a canceling signal given to a combiner 2 through a distributor 4, a transmitting antenna 5, and a receiving antenna 1. The delay time (depending on the length of the interval between the receiving antenna 1 and the transmitting antenna 5) of the interference signal that is given to the combiner 2 is eliminated by the variable delay unit 6, and the amount of cancellation of the interference signal by the cancellation signal is reduced. It is made large as a whole regardless of the frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to various radio services such as a car phone, a cellular phone, and a radio paging device. In the open space such as a shade of a mountain, radio waves related to the various radio services do not reach and a service insensitive zone occurs. The present invention relates to a wireless relay amplifying device used for preventing such a situation.

[0002]

2. Description of the Related Art FIG. 2 shows an example of the configuration of a conventional wireless relay amplifier used for the above purpose. In FIG. 1, a receiving antenna 1 is installed at a point where radio waves related to a signal to be subjected to relay amplification can be received (a point not in the service dead zone), for example, at the top of a mountain or the like. This is an antenna for sending and receiving only. The combiner 2 receives the received signal sent from the receiving antenna 1 and
This is a circuit unit that combines a canceling signal sent from a variable attenuator 8 described later, and sends a signal obtained by the combination to the bandpass filter 9. The bandpass filter 9 is a circuit unit that limits the band of the signal sent from the combiner 2 and sends the obtained signal to the power amplifier 3. The power amplifier 3 is a circuit section which receives the signal sent from the bandpass filter 9, amplifies the signal, and outputs the amplified signal. The distributor 4 is specifically a directional coupler, takes in the signal transmitted from the power amplifier 3, and distributes the signal to the transmission antenna 5 and the variable phase shifter 7 described below. This is the circuit section that sends out. The transmission antenna 5 is a transmission-only antenna for transmitting the signal transmitted from the distributor 4 as a radio wave, and transmits the radio wave to a desired area (specifically, the service dead zone).
(For example, at the center of the above-mentioned service dead zone).

[0003] The variable phase shifter 7 takes in the above-mentioned signal sent from the distributor 4, and the signal goes from the transmitting antenna 5 to the receiving antenna 1 in the combiner 2 and is sent to the combiner 2. In order to be in phase with the incoming interference signal (more precisely, so that the center frequency signal of both signals is in phase), the phase of the signals is shifted to obtain an inverted phase signal, and the inverted phase signal is transmitted. Circuit. Since the variable phase shifter 7 is variable, the amount of phase shift at the time of shifting the phase can be adjusted according to the distance from the transmission antenna 5 to the reception antenna 1 of each wireless relay amplifier. The variable attenuator 8 receives the reverse phase signal from the variable phase shifter 7 and
A circuit for obtaining the canceling signal by making the amplitude of the opposite phase signal equal to the instantaneous amplitude of the interference signal sent to the combiner 2 every moment, and sending the canceling signal to the combiner 2 Department.

In the conventional radio relay amplifying device having the above-described configuration, the same signal is split into two by the splitter 4,
One is supplied to the transmission antenna 5 and the other is supplied to the variable phase shifter 7. The signal given to the transmitting antenna 5 is sent out as a radio wave, and a part of the signal goes to the receiving antenna 1 and is given to the combiner 2 as the interference signal. On the other hand, the signal provided from the distributor 4 to the variable phase shifter 7 is subjected to a phase shift process (a center frequency The signal is focused on the signal) and is supplied to the variable attenuator 8 as a negative-phase signal. The opposite-phase signal is subjected to amplitude adjustment processing by the variable attenuator 8 in the combiner 2 so as to have the same amplitude as the interference wave, and is provided to the combiner 2 as a canceling signal. The combiner 2 combines the interference signal and the canceling signal. Since the canceling signal has a phase opposite to that of the interference signal and has the same amplitude, the interference signal is canceled by the canceling signal and erased. . In this way, the disadvantage caused by the interference signal from the transmitting antenna 5 to the receiving antenna 1, that is, the oscillation of the wireless relay amplifier is avoided.

[0005]

By the way, the phase shift processing in the variable phase shifter 7 in the conventional wireless relay amplifying apparatus as described above is performed only on the center frequency signal of the frequency band of the signal to be relay amplified. The present invention focuses attention on the central frequency signal in the canceling signal and makes the central frequency signal in the interference signal have an opposite phase. That is, the phase shift processing does not make the interference signal and the canceling signal have opposite phases in all frequency bands.

On the other hand, the installation interval between the receiving antenna 1 and the transmitting antenna 5 of such a wireless relay amplifying device varies depending on the topography of the installation site and the like, and may be several tens of meters or several hundred meters. May reach. Therefore, a large difference occurs between the interference signal path and the cancellation signal path, and the interference signal is delayed with respect to the cancellation signal, and the delay time varies according to the interval between the reception antenna 1 and the transmission antenna 5. become.

[0007] The effect of the phase shift processing focusing only on the center frequency signal becomes more remarkable as the delay time becomes longer. FIG. 3 shows this state. Cancellation amount by canceling signal of the interference signal as shown in the figure in the center frequency f _0, is constant regardless of the length of the delay time, the frequency away from the center frequency f _0, a long delay time In that case the amount of cancellation is greatly reduced. For this reason, when the distance between the two antennas is extremely long, the canceling effect by the canceling signal is significantly reduced in the entire use frequency band.

[0008] The present invention has been made in view of the above-mentioned circumstances, and even if the interval between the receiving antenna and the transmitting antenna is long, the amount of cancellation of the interference signal by the canceling signal can be reduced over the entire use frequency band. It is an object of the present invention to provide a wireless relay amplifying device that can be sufficiently secured even when viewed from the above.

[0009]

According to the first aspect of the present invention, a wireless relay amplifying device is configured as follows. That is, a receiving antenna installed at a point where radio waves related to a signal to be subjected to relay amplification can be received, a received signal received by the receiving antenna, and a canceling signal transmitted from a variable attenuator described below. A synthesizer for transmitting the signal obtained by the synthesis, a band filter for inputting the signal sent from the synthesizer, and limiting the band to only the used frequency and transmitting the same, A signal sent from the filter is input, a power amplifier for amplifying and sending the signal, and the signal sent from the amplifier are input,
A distributor for distributing this signal to a transmission antenna and a variable delay device to be described later and transmitting the signal, a transmission antenna for transmitting the signal transmitted from the distributor as a radio wave, and the signal transmitted from the distributor. Input, the signal, in the combiner, so as to have the same delay time as the interference signal that has wrapped around from the transmitting antenna to the receiving antenna, to give a constant delay time to the signal and output a delay unit Inputting the signal output from the delay unit, performing a phase shift process on the signal so that the center frequency signal of the signal is in the opposite phase to the center frequency signal of the interference signal, The phase shifter that outputs the negative phase signal and the negative phase signal output from the phase shifter are input, and the amplitude of the negative phase signal is attenuated to be equal to the amplitude of the interference signal. Then cancel To obtain a use signal and the canceling signal is configured to include a variable attenuator to be sent to the synthesizer.

According to a second aspect of the present invention, in the wireless relay amplifier according to the first aspect of the present invention, the delay unit is a variable delay unit, and the phase shifter is a variable phase shifter.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be specifically described based on one embodiment of the present invention. FIG. 1 shows the configuration of the embodiment. As can be seen from the figure, this embodiment has a configuration in which a variable delay device 6 is newly connected between the distributor 4 and the variable phase shifter 7 having the configuration of FIG.

In FIG. 1, the same reference numerals as in FIG. 2 are used for the circuit units having the same configuration and the same functions as those in FIG. 2 showing a conventional example. However, description of these circuit units will be omitted.

The variable delay unit 6 in FIG. 1 receives the signal sent from the distributor 4 so that the signal has the same delay time in the combiner 2 as the interference signal caused by the wraparound. This circuit gives a delay to the signal (a large delay when the interval between the receiving antenna 1 and the transmitting antenna 5 is long, and a relatively small delay when the interval is relatively short).

In this embodiment in which the variable delay device 6 is added, the receiving antenna 1 and the transmitting antenna 5
Regardless of the length of the interval between the canceling signal and the receiving antenna 1 provided to the synthesizer 2 from the variable attenuator 8.
3 has a small (or extremely small) delay with respect to the interfering signal given to the combiner 2 from FIG.
In, a large cancellation amount can be obtained regardless of the frequency of the cancellation amount indicated by the broken line or higher.

In this embodiment, as in the conventional example, the phase shifter is a variable phase shifter 7 and the variable delay device 6 is used as a delay device for the purpose of the above-mentioned delay. Even if the distance between the receiving antenna 1 and the transmitting antenna 5 changes according to the topography of each point where the amplifying device is installed and the delay time or the like changes, it can cope with them.

[0016]

As described above in detail, according to the present invention, even if the interval between the receiving antenna and the transmitting antenna becomes long, the amount of cancellation of the interference signal by the canceling signal is viewed in the entire use frequency band. Even so, it is possible to provide a wireless relay amplification device that can be sufficiently secured.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a conventional example.

FIG. 3 is a diagram showing the relationship between the magnitude of a delay time and the amount of cancellation in the above conventional example.

[Description of Signs] 1 reception antenna 2 combiner 3 power amplifier 4 distributor 5 transmission antenna 6 delay variable device 7 variable phase shifter 8 variable attenuator 9 bandpass filter

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masato Doguchi 3-14-20 Higashinakano, Nakano-ku, Tokyo Inside Kokusai Denki Co., Ltd. (72) Inventor Kazuto Ito 2-1-1 Toranomon, Minato-ku, Tokyo N・ TTI Mobile Communication Network Co., Ltd. (72) Inventor Hiroshi Suzuki 1964 Makin, Miyamae-ku, Kawasaki City, Kanagawa Prefecture

Claims (2)

[Claims] 1. A receiving antenna installed at a point where radio waves related to a signal to be subjected to relay amplification can be received, a received signal received by the receiving antenna, and a cancel signal transmitted from a variable attenuator described later. A combiner that combines the signals for use and sends out the signal obtained by the combining; a bandpass filter that receives the signal sent from the combiner and limits the band to only the used frequency and sends it out. A power amplifier that receives a signal sent from the bandpass filter, amplifies the signal, and sends the signal; and receives the signal sent from the amplifier, and transmits the signal to a transmission antenna and a variable delay device described later. And a transmitting antenna for transmitting the signal transmitted from the distributor as a radio wave; and inputting the signal transmitted from the distributor, and the signal is combined with the composite signal. A delay unit for giving a fixed delay time to the signal so as to have the same delay time as an interference signal that has diverted from the transmission antenna to the reception antenna, and a signal output from the delay unit Is input to the signal, a phase shift process is performed on the signal so that the center frequency signal of the signal is in phase opposite to the center frequency signal of the interference signal, an inverted signal is obtained, and the inverted signal is output. A phase shifter, and the negative phase signal output from the phase shifter is input, and the amplitude of the negative phase signal is attenuated to be equal to the amplitude of the interference signal to obtain the canceling signal. And a variable attenuator for transmitting the canceling signal to the combiner. 2. The wireless relay amplifying device according to claim 1, wherein said delay device is a variable delay device, and said phase shifter is a variable phase shifter.