JPS61278223A - Antenna system - Google Patents

Abstract

PURPOSE:To apply optimum control to the direction of the combined directivity in a short time by providing a directivity characteristic control means directing the combined directivity in a direction to control a reception signal adjusting device so as to obtain the best reception state based on the storage value of a storage means when the deterioration of the reception state is detected. CONSTITUTION:The combined directivity of the entire antenna synthesized by a synthesizer 41 depends on the phase of the reception wave at signal adjusting devices 31-34 and the adjustment quantity of the output level. That is, the phase and output level of the reception wave received by antennas 21-24 are adjusted properly. A directivity controller 60 detects always the reception state of the receiver 42 based on the output of a reception state detector 43 and controls the phase of the reception wave and the adjustment quantity of the output level by each antenna based on the table of a storage section 62 when the reception state is deteriorated. Then the antenna directing beam is directed in the direction to obtain the best reception state.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides the best reception by controlling the direction of the combined directivity characteristic of the entire antenna obtained by combining the outputs of a plurality of antennas installed on a moving body. The present invention relates to an antenna device that maintains a state.

[Technical Background] In general, antennas for mobile objects, such as vehicle antennas,
As shown in Figure 7, a whip antenna 1 is installed on 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. 8, 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 1
When trying to receive FM broadcasts in the frequency band 0 to 90M1-17 while driving in a city, as shown in Figure 9, the direct waves of the broadcast radio waves and the reflected waves reflected by buildings etc. are simultaneously received. Multipath reception may occur. In such a case, the omnidirectional whip antenna 1 receives the direct wave and the indirect wave at approximately the same level, resulting in a decrease in the received electric field level or generation of echo distortion, which impedes good reception. Furthermore, when driving in an area with a weak electric field, the electric field constantly changes due to the movement of the vehicle, and the signal may be received with so-called "skip noise".

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

[Prior Art] As such an active antenna, there is conventionally one such as shown in FIG. 10, for example.

(Japanese Unexamined Patent Publication No. 54-32022> Figure 10 shows an active antenna for television, 2.3 is an antenna with almost the same characteristics, 4 is an antenna with almost the same characteristics,
5 is a received signal conditioner that adjusts the output of the antenna 2, and 5 is a synthesizer that combines the outputs of the antennas 2.3 and inputs the synthesized signal to a 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 8 that extracts a vertical synchronization signal S2 and a horizontal synchronization signal S3 from the video signal $1 outputted by the receiver n6; and a sampling signal generation circuit 9 which outputs a sampling signal S4 for sampling the ghost component of the color burst signal of the video signal S1 from these two Domei signals 32 and 33.
, a sampling circuit 10 that samples a ghost component S5 of the color burst signal from the video signal S1 using this sampling signal S4, and a ghost burst amplification/detection circuit 11 that amplifies and detects this ghost component S5 and outputs a detected voltage S6. It consists of 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 operates as follows. That is, when the detection voltage Se is input from the ghost burst amplification/detection circuit 11, the phase level adjustment (■) of the received signal conditioner 4 is adjusted from 0 degrees to 360 degrees on the first cycle day.
The minimum value of the detected voltage S6 is stored.

Next, on the second cycle day, the received signal conditioner 4 is phase-shifted again, and when the detected voltage S6 output from the ghost burst amplification/detection circuit 11 becomes equal to the minimum value stored on the first cycle day, This is to stop the phase shifting operation of the received signal adjuster 4.

In this way, the directional characteristic control device 12 controls the directional characteristics of the combined antennas, so that the receiver 6 is brought into the best reception state.

[Problems to be Solved by the Invention] By the way, such conventional antenna devices combine the outputs of multiple antennas with the same characteristics, and the receiving station is not connected to the home television. This was done on the assumption that it was a fixed receiving station.

However, in the case of antennas that are mounted on the vehicle body, such as vehicle antennas, even if the antenna has the same characteristics, it is affected by the vehicle's metal body, etc., so the characteristics may change in the mounted state. It is extremely difficult to obtain multiple antennas that are aligned.For example, even if a whip antenna that is omnidirectional in free space is attached to a vehicle, each antenna will have directionality. In a mobile receiving station, noise generation cannot be effectively prevented even if the above-mentioned antenna device, which is based on a fixed receiving station, is applied.In a mobile receiving station, the reception status changes as the mobile object moves. Therefore, it is extremely difficult to optimally control the directivity direction in a short time using antennas with uneven characteristics.

[Means for Solving the Problems] The present invention has been made to solve the above problems, and even if the receiving conditions change frequently as the moving object moves, the combined directivity of each antenna can be maintained. The purpose is to provide an antenna device that can optimally control the direction in a short time and always maintain the best reception condition. The present invention has a structure in which storage means is provided in which the amount of adjustment of each antenna output is stored in advance, and directional characteristic control means is provided for controlling the received signal adjuster based on the storage means.

[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 1, 21°22.23.24
is an antenna installed on a moving body such as a vehicle, and its output is input to a received signal conditioner 31, 32, 33, and 34. This received signal adjuster 31.32.33.34 adjusts the phase and output level of the received wave received by each antenna 21.22.23.24 and outputs the adjusted signal. The adjusted signals output from the received signal adjuster 31, 32, 33, and 34 are combined by the combiner 41 and sent to the receiver 4.
2 is input. At this time, the combined directivity of the entire antenna combined by the combiner 41 is determined by the received signal conditioner 3
It is determined by the amount of adjustment of the phase and output level of the received wave at 1, 32, 33, and 34. That is,
By appropriately adjusting the phase and output level of the received waves received by each antenna 21, 22, 23, 24, the composite directivity of the entire antenna becomes sharp with respect to the direction of arrival of the radio waves, as shown in Figure 2. At the same time, the beam direction (the longest direction of the directional characteristics) can also be changed arbitrarily. 42 is a receiver that receives and demodulates the composite signal from the combiner 41; 43 is a reception state detector that detects the output level of the receiver 8142 to detect the reception state of the receiver 42; and 44 is a speaker.

60 inputs the output signal of the receiving state detector 43 and controls the amount of adjustment of the phase and output level of the received wave in the received signal adjuster 31, 32, 33, 34 to change the combined directivity characteristic of the entire antenna. This is a directional characteristic control device.

Specifically, this directional characteristic control device 60 is configured to control, for example, the third
As shown in the figure, the storage unit 62. Control unit 63. and interface circuits 64 and 65. In the storage unit 62, as shown in FIG.
A table representing the adjustment amount of the phase and output level of the received wave at 32.33°34 is stored in advance,
It outputs necessary information in response to a call from the control unit 63. This daple includes figures 4 and 5 (a).
As shown in ~(f''), the combined directivity characteristic when four antennas are combined is sharpened in a certain direction (for example, considering the relative coordinate system with the front of the vehicle as 0 degrees), and the direction of the beam is set to 360 degrees. ■Adjust the level and phase of each antenna output necessary to rotate the beam in each direction (
30') are summarized in a table. Note that since the amount of adjustment of the phase and output level of each antenna differs depending on the frequency, a table needs to be recorded for each frequency. Further, the numerical values in the table may be obtained in advance by actual measurement, analysis, etc.

On the other hand, the control unit 63 controls the direction of the directional beam to obtain the best reception condition.

That is, this directional characteristic control device 60 constantly detects the receiving state of the receiver 42 based on the output of the receiving state detector 43, and when the receiving state becomes bad, it displays the information in the table of the storage unit 62 and updates each antenna. This is to control the amount of adjustment of the phase and output level of the received wave by directing the directional beam of the antenna in the direction that provides the best reception condition.

Next, the operation of the antenna device according to this embodiment will be explained.

First, at the same time that the power of the receiver 42 is turned on, the directional characteristic control device 60 receives a voltage signal corresponding to distortion such as multipath included in the received wave outputted from the reception state detector 43 and is stored in advance. The reception status of reception Iff 4°2 is monitored by comparing it with the standard value. Then, as long as the reception condition is good, the reception condition continues to be monitored.

10,000, when the reception condition deteriorates, that is, when the output signal from the reception condition detector 43 becomes larger than the reference value, the control section 63 stores information in the table of the storage section 62 so that good reception can be performed. Memorized values (beam direction of composite directional characteristic: o'', 30°, 60° -++ 41
144114.Specify the stored value corresponding to the beam direction that increases the current beam direction by 30° from the amount of adjustment of the phase and output level of each antenna output to direct it to 360°, and adjust each received signal based on the stored value. Adjustment interval 31.32
．． 33 and 34, the beam direction of the composite directional characteristic is switched, and the reception state in each beam direction is determined. At this time, if the reception condition is still not good, change the beam direction three times until a good reception condition is obtained.
The stored values are sequentially specified in increments of 0°.

This allows the combined directivity to be controlled in the beam direction in which a good reception condition can be obtained. Thereafter, the receiving state is continued to be monitored in that state, and if the receiving state deteriorates, the beam direction of the directional characteristic is again controlled as described above to obtain the best receiving state. As described above, according to the antenna device according to this embodiment,
Directional characteristic control! Since the II device 60 stores in advance a table showing the amount of adjustment of the phase and output level of each antenna output in order to orient the composite directivity of the entire antenna in a desired direction, it can be used in a short time even when the reception condition deteriorates. The directional characteristic beam direction can be changed so that the best reception condition can be obtained at any time, making it possible to always perform good reception.

FIG. 6 shows another embodiment of the invention. The antenna device according to this embodiment is provided with two receivers: a mask receiver 46 used exclusively for tuning and demodulation, and a slave receiver 47 used exclusively for beam direction detection. A dedicated synthesizer 45 is connected to the mask receiver 46, and a dedicated received signal conditioner 35.
7.38 was established.

In this antenna device, '#J device 60 according to directional characteristics
constantly monitors the reception state in the slave receiver 47 based on the output of the reception state detector 43. When poor reception occurs, the storage unit 62
The received signal conditioners 31, 32, 33 .
34 to detect the beam direction that provides the best reception condition. Then, when the beam direction is determined, each received signal adjuster 35, 36, 37 connected to the mask receiver 46
．． 38 to instantly switch the beam direction to the direction of arrival of the direct wave. This makes it possible to eliminate noise reproduced by the speaker 44 when detecting the beam direction with the best reception condition.

In the above embodiment, the number of antennas is four, but the number of antennas is not limited to four as long as there are a plurality of antennas. In addition, although it has been explained that the beam direction of the directional characteristic is controlled to be directed in the direction of arrival of the direct wave, it is also possible to control the dip of the directional characteristic (the shortest direction of the directional characteristic) to be directed in the direction of the reflected wave or indirect wave. It may be controlled to cut indirect waves.

Furthermore, it goes without saying that the receiver 42 may be another communication device such as a TV in addition to radio reception. Further, in the table shown in FIG. 5, if the angular step of the beam direction of the directional characteristic is made finer, more precise reception state control can be realized.

[Effects of the Invention] As explained above, the present invention provides a storage section in which the amount of adjustment of each antenna output for directing the composite directional characteristic of the entire antenna in an arbitrary direction is provided, and the stored value of the storage section is The direction of the combined directivity of the entire antenna is controlled based on the direction of the combined directivity of each antenna. This has the effect that it is possible to provide an antenna device that can perform optimal control in a short time and can always maintain the best reception state.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an antenna device according to the present invention,
FIG. 2 is an explanatory diagram showing the combined antenna directivity characteristics, FIG. 3 is a block diagram showing the configuration of the directivity control device according to the embodiment of the present invention, and FIG. 4 is the phase/output in each received signal conditioner. A table showing the relationship between the amount of level adjustment and the beam direction of the directional characteristic, FIG. 5 is an explanatory diagram showing the direction of the directional characteristic of the combined antenna, and FIG. 6 shows an antenna device according to another embodiment of the present invention. A block diagram, FIG. 7 is a perspective view showing the whip antenna, FIG. 8 is an explanatory diagram showing the directional characteristics of the whip antenna, FIG. 9 is an explanatory diagram showing direct waves and indirect waves received by a running vehicle, FIG. 10 is a block diagram showing a conventional antenna device. 21.22.23.24...Antenna 31.32.3
3.34 35.36.37.38... Reception signal conditioner 41.4
5...Synthesizer 42, 46, 47...Receiver 43...Reception state detector 60...Directional characteristic control device 62...Storage unit 63...Control unit 11th! I Figure 2 Figure 31!3 Figure 4 Figure 7 Figure 8 Figure 9 Figure 5 (o) O' (b) 30' (c)
60'

Claims (1)

[Claims] A plurality of antennas installed on a mobile object, a received signal conditioner that adjusts the output of each antenna, a combiner that combines the output of the received signal conditioner and inputs it to the receiver, and detects the reception state of the receiver. a reception state detector for detecting a received state, a storage means in which each antenna output adjustment amount for directing the composite directional characteristic of the entire antenna in an arbitrary direction is stored in advance; and directivity control means for directing the combined directivity in a direction that provides the best reception condition by controlling a received signal adjuster based on the stored value in the storage means. .