JPS6269734A - Antenna system - Google Patents

Abstract

PURPOSE:To obtain an excellent reception state in any types of movable bodissby storing the synthesized ratio of the phase and level of each antenna output in a storage means in accordance with the shape of the movable body on which an antenna system is mounted and its specifications. CONSTITUTION:When the power source of a receiver 2 is turned on, a directivity controller 61 minitors the reception state of the receiver 42. If the reception state deteriorates, the directivity controller 61 specifies the beam direction fine adjustment quantity of the synthesized directivity stored on the table of the storage device 60. Phase level adjusting devices 31-34 are controlled based on the stored value to switch the beam direction of the synthesized directivity, and simultaneously the reception state in the beam direction is decided. If the reception state is not yet excellent, storage values increasing the beam direction by 10 deg. are sequentially specified until the excellent reception state can be controlled in the beam direction where the excellent reception state can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a receiving device, in particular, to controlling the combined directivity characteristics of the entire antenna obtained by combining the outputs of a plurality of antennas installed on a moving object. The present invention relates to an antenna device that maintains good reception conditions.

[Technology background]

Generally, antennas for mobile objects, such as vehicle antennas,
As shown in Figure 5, a whip antenna l is attached to a part of the vehicle C.
It is made up of the following. Since the directional characteristics of the whip antenna 1 are relatively fixed as shown in FIG. 6, it is designed so that the receiving sensitivity does not change much no matter which direction the vehicle C faces.

However, using the whip antenna l,
When trying to receive FM broadcasts in the 90MHz frequency band while driving in a city, as shown in Figure 7,
The direct wave of the transmission wave and the reflected wave R reflected by building B etc.
Multipath reception may occur in which both are received at the same time. In such a case, with an omnidirectional whip antenna,
Direct waves and indirect waves are received at approximately the same level, resulting in a drop in the received electric field level or generation of echo distortion, which impedes good reception. In addition, when driving in areas with weak electric fields, the electric field constantly changes due to the movement of the vehicle, causing "rough, rough"
It may be received with so-called skip noise.

An effective means for preventing such skip noise and the like is an antenna device (active antenna) that controls the directivity characteristics of an antenna by phase-combining a plurality of antennas.

[Conventional technology]

As such an antenna device, there is a conventional antenna device as shown in FIG. 8 (Japanese Patent Application Laid-Open No. 54-32022).
.

Figure 8 shows an active antenna for television, where 2.3 is an antenna with substantially the same characteristics, 4 is a received signal conditioner that adjusts the output of antenna 2, and 5 is an antenna that adjusts the output of antenna 2.3. This is a synthesizer that combines the signals and inputs them to the receiver (receiver) 6.

7 is a reception state detection circuit that detects the reception state of the receiver 6; specifically, a synchronization signal detection circuit that extracts a superimposed synchronization signal S2 and a horizontal synchronization signal S3 from the video signal St output from the receiver 6; 8 and these two synchronization signals S2 and S3
A sampling signal generation circuit 9 outputs a sampling signal S4 for sampling the ghost component of the color burst signal of the video signal S+ from the video signal St, and uses this sampling signal S4 to sample the ghost component S5 of the color burst signal from the video signal St. The ghost burst amplification and detection circuit 11 amplifies and detects this ghost component S5 and outputs a detected voltage S6. Reference numeral 12 denotes a directional characteristic control device which changes the directional characteristic of the antenna by inputting the detected voltage S6 and controlling the received signal adjuster 4 so that the detected voltage S6 is minimized.

Specifically, this directional characteristic control device 12 operates as follows. That is, the ghost burst amplification and detection circuit 11
When the detected voltage S6 is input from
The minimum value of the detected voltage S6 is memorized by varying it within a range of 60 degrees.Next, the received signal adjuster 4 is phase-shifted again on the second interval, and the detected voltage output by the ghost burst amplification/detection circuit 11 is changed. The phase operation of the received signal conditioner 4 is stopped when S8 becomes equal to the minimum value stored on the first cycle day. In this way, the directional characteristic control device 12 controls the directional characteristics of the combined antennas, so that the receiver 26 is brought into a good receiving state.

[Problem that the invention seeks to solve]

By the way, such conventional receiving devices combine the outputs of multiple antennas with uniform characteristics, and also assume that the receiving station is a fixed receiving station such as a home television. This was done as a.

However, in the case of antennas that are generally mounted on the car body, such as vehicle antennas, even if antennas with uniform characteristics are installed, the characteristics will change due to the influence of the vehicle metal body etc., and the characteristics will change when installed. Obtaining a book antenna is extremely difficult. For example, even if whip antennas with landscape directionality are attached to heavy vehicles in the free sky, each antenna will have directivity.Moreover, if a mobile receiver such as a vehicle (in a clear station, the reception status changes frequently as the moving object moves) Therefore, it is extremely difficult for conventional receiving apparatuses to optimally control the combined directivity so as to improve the reception condition in a short time using antennas with uneven characteristics.

Therefore, in order to solve this problem, the applicant of the present invention wrote down the combination ratio of each antenna output! proposed an antenna device that controls the composite directional characteristics of the entire antenna based on the stored memory stage (Utility Application No. 6O-119700).

However, the directivity of each antenna differs depending on the body shape and antenna specifications of the moving object (for example, a vehicle) on which the antenna device is mounted, so if the combination ratio of each antenna output stored in the storage means remains the same, If the vehicle models are different, the desired composite directional characteristics cannot be obtained.

Therefore, an object of the present invention is to make it possible to obtain composite directivity characteristics of a plurality of pre-selected patterns even if the shape of the moving body or antenna specifications change.

[Means for solving problems]

In order to solve the problems in Section L and accomplish the tasks.

The present invention stores in a storage means the phase and level synthesis ratio of each antenna output to obtain a composite directional characteristic of a plurality of patterns selected in advance according to the shape and antenna specifications of a mobile object on which an antenna device is to be mounted. This is what I did.

[Effect]

In the device of the present invention, when reception is poor, the directivity control means controls the phase level adjuster so that the combination ratio of the phase levels of the outputs of each antenna changes based on the information in the storage means. Then, the composite directional characteristic at the time of poor reception is switched to other composite directional characteristics of a plurality of patterns selected in advance. If the received signal becomes good due to the composite directional characteristics, that state will be maintained,
On the other hand, when the reception condition is poor even with that composite directional characteristic, the composite directional characteristic is further switched to another composite directional characteristic. In this way, even if the reception condition deteriorates due to the movement of the mobile object, the composite directional characteristics can be switched instantaneously, so that a good reception condition can be maintained. In addition, in the present invention, the combination ratio of each antenna output is determined in advance for each type of mobile object to be mounted,
Since it is stored in the storage means, it is possible to obtain composite directivity characteristics of a plurality of patterns selected in advance using the same antenna device, regardless of the type of moving body.

〔Example〕

Hereinafter, the present invention will be described in detail based on the accompanying drawings.

FIG. 1 shows an antenna device according to an embodiment of the present invention. In this figure, numerals 21 to 24 are antennas provided on moving bodies such as 1p and both, and their outputs are input to phase level adjusters 31 to 34. The phase level adjusters 31-34 adjust the phase and output level of the output of each antenna 21-24. The signals output from the phase level adjusters 31 to 34 are combined by a combiner 41 and input to a reception number 42. At this time, the combined directivity characteristics of the entire antenna combined by the combiner 41 are determined by the combination ratio of the phases and output levels of the received waves in the 1-phase level adjusters 31 to 34. Reference numeral 43 denotes a reception state detector that determines whether the reception state of the receiver 42 is good or bad. 60 is a storage device;
As shown in FIG. 2, adjusters for each antenna output necessary for directing the beam direction of the composite directional characteristic toward the arrival direction of the direct wave are stored in advance. The table shown in FIG. 3 sharpens the composite directional characteristic when combining the four antennas 21 to 24 in a specific direction (for example, considering the relative coordinate system with the front of the vehicle as 06), and the table shown in FIG. Adjustment of the phase and level of each antenna output required to rotate its beam direction 3600 times per preselected pattern.
, wrinkles are grouped by beam direction (for example, by lOo). The numerical values necessary for controlling such composite directional characteristics are determined in advance through actual measurements and analysis, but since antenna specifications and i1j body shapes differ depending on the vehicle model, the phase and The level adjusters are grouped together in a table for each model, and replaced depending on the type of car in which the receiver is installed. Note that since the phase and level adjusters for each antenna differ depending on the frequency, it goes without saying that a table for each frequency is required.

Reference numeral 61 inputs the output signal from the reception state detector 43, reads information necessary for controlling the composite directional characteristic from the storage device 60, and adjusts the phase and level in the phase level adjusters 31 to 34. This is a directional characteristic control device that changes the composite directional characteristic of the entire antenna by controlling the antenna. Note that 44 is a speaker.

Next, the operation of this receiving device will be explained.

First, at the same time as the power of the receiver 42 is turned on, the directional characteristic control device 61 receives a voltage signal corresponding to distortion such as multipath contained in the received wave outputted from the reception state detector 43 and is stored in advance. By comparing with the standard value,
Monitor the reception status of Reception@42. Then, as long as the reception status is good, the reception status continues to be monitored.

On the other hand, when the reception condition deteriorates, that is, when the output signal from the reception condition detector 43 becomes larger than the reference value, the directional characteristic control device 61 updates the table in the storage device 60 so that good reception can be performed. The stored memory values (beam direction of composite directional characteristic are set to 0', 10°, 20°)
°...

Specify a stored value corresponding to the beam direction in which the current beam direction is increased by 100 (adjustment amount of the phase and output level of each antenna output to direct it to 3600), and adjust each phase level adjuster 31 to 31 based on the stored value. By controlling 34, the beam direction of the composite directional characteristic is switched, and the receiving state in the beam direction is determined. At this time, if the reception condition is still not good, the beam direction is sequentially specified to increase the beam direction by lO0 until a good reception condition is obtained. The composite directivity can be controlled.

That is, by adjusting the phase and output level of the received waves received by each of the antennas 21 to 24 to 31g as appropriate, the composite directivity characteristics of the entire antenna become sharp with respect to the direction of arrival of the radio waves, as shown in FIG. The beam direction (the longest direction of directional characteristics) can also be changed arbitrarily. After that, monitor the reception status in that state! If the receiving condition continues to deteriorate, the beam direction of the directional characteristic is controlled again as described above to obtain a good receiving condition.

As described above, according to the antenna device according to this embodiment, the phase and output level of each antenna output necessary to form the composite directivity of the entire antenna of a plurality of patterns selected in advance is stored in the storage bag'll160. Since a table representing the amount of adjustment is stored, the directional beam direction can be changed so that good reception conditions can be obtained in a short time even when reception conditions deteriorate, and it is possible to always maintain good reception. It becomes usable.

In addition, in the above embodiment, the number of antennas was explained as four, but the number of antennas is not limited to four as long as there are multiple antennas. Although the explanation has been given as controlling to direct the directivity, it is also possible to control the dip of the directivity (the shortest direction of the directivity) in the direction of the reflected wave or indirect wave, thereby cutting the indirect wave. , furthermore, the receiver 42
Of course, it may be a radio receiver or other communication device such as a TV. Further, in the table shown in FIG. 3, if the beam direction angle brackets of the directional characteristics are made finer, more precise reception state control can be realized.

〔Effect of the invention〕

As explained above, the antenna device according to the present invention combines the outputs of each antenna necessary to form a composite directional characteristic of a plurality of patterns selected in advance according to the shape and antenna specifications of the mobile object on which the antenna device is installed. Since the ratio is stored, the same antenna device can be mounted on other mobile bodies simply by changing the stored value, and good reception conditions can be obtained in various mobile bodies.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a configuration example of an antenna device according to the present invention, FIG. 2 is an explanatory diagram showing the combined antenna directivity characteristics, and FIG. 3 is a phase/output level adjuster in each received signal adjuster. Figure 4 is an explanatory diagram showing the directional characteristic pattern of the synthesized antenna, Figure 5 is a perspective view showing the whip antenna, and Figure 6 shows the directional characteristic of the whip antenna. FIG. 7 is an explanatory diagram showing direct waves and indirect waves received by a running vehicle, and FIG. 8 is a block diagram showing a conventional antenna device. 21.22.23.24...Antenna 31.32,3
3.34...Phase level adjuster 41...Synthesizer 42...Receiver 43...Reception status detector 60...Storage device 61...Directional characteristic control device Patent applicant Nissan Motor Co., Ltd. Company@II! 1 Just love 2 Figure 3 Figure 5 Figure 62
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Claims (1)

[Claims] A phase level adjuster adjusts the phase and level of the received waves received by each antenna of multiple antennas installed on a mobile object, and the entire antenna is synthesized by combining the outputs of each antenna adjusted by this phase level adjuster. In an antenna device having a combiner that forms a directional characteristic,
A storage means that stores a combination ratio of each antenna output to obtain a composite directional characteristic of a plurality of preselected patterns according to the shape and antenna specifications of a mobile object on which the antenna device is to be mounted, and 1. An antenna device comprising directional characteristic control means for forming a specific pattern of composite directional characteristics by driving a level adjuster.