JPH0327073B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a device for measuring electromagnetic waves generated as noise by various electronic and electrical devices.

(Technical Background and Prior Art) Conventionally, interference waves from various electronic and electrical devices,
It is known that so-called noise occurs. For example, suppose that a TV is placed in a certain electrode environment and a refrigerator starts up, a fluorescent light flashes, or an electric razor is used near the TV. We have all experienced situations where the TV image becomes confusing or noise is mixed into the audio.
This is because noise is generated from electronic and electrical devices other than the television, and the television is affected by this noise.In the current situation where various electronic and electrical devices exist, so-called electromagnetic interference (EMI) occurs.
This is a phenomenon that has become more apparent in recent years.

By the way, in order to find out how much noise of this kind is generated in various electronic and electrical devices, and how effective the solutions are, it is necessary to accurately and accurately measure the electromagnetic waves generated as noise. It needs to be done objectively. Moreover, the demand for such electromagnetic wave measurements has been increasing in recent years. The main measurement conditions for such electromagnetic wave measurement results to be accurate and objective are as follows.

The reflective surface (earth or floor) at the measurement location must be completely uniform and flat.

Buildings, trees, etc. that adversely affect electromagnetic wave measurements
Wires and other objects must be far away from the measurement location.

The measuring equipment or the hut for the measuring personnel does not influence the electric field.

The various equipment required to measure electromagnetic waves must not disturb the electric field around the antenna.

In order to satisfy the above conditions ~, there is no problem if the measuring device is relatively small (the distance from the device under test to the antenna is approximately 3 m), but there is no problem between the device under test and the antenna. If you need a large one with a distance of about 30m,
It becomes difficult to satisfy the conditions of ~. The reason why such a large measuring device is required is as follows. In other words, in order for electromagnetic wave measurement results to be accurate and objective, it is necessary to measure only the electromagnetic waves generated by the device under test. A complete electromagnetic anechoic chamber, that is, an electromagnetic wave reflection-free chamber, must be created by applying advanced processing and processing to prevent electromagnetic waves from being reflected, which makes the device as a whole quite expensive.

In recent years, as electrical and electronic equipment that is a source of noise has become larger, it is necessary to take into account not only the electrical and electronic equipment located nearby, but also the impact on electrical and electronic equipment located quite far away. Therefore, it is not possible to simply measure the influence within a range of about 3 meters and apply the results to objects located far away.

It is necessary to minimize reflections other than electromagnetic waves from the ground to give objectivity to the measurement results.In other words, in order to prevent electromagnetic wave reflections from having a large influence on measurements, a large measurement space is required. must be ensured.

etc.

10 electromagnetic wave measurement devices that have already been developed
As shown in FIG. 1, a metal floor 11 is located at a predetermined height above the ground, and a turntable 12 that is rotated by the operation of an electric motor is disposed on one side of the metal floor 11. On this turntable 12, an electrical/electronic device W, which is a device to be measured, is placed. And turntable 1
2 is covered with a shelter 14 made of hard plastic to protect the equipment W located inside. Furthermore, an antenna 13 for capturing electromagnetic waves is disposed on the other side of the metal floor 11. The antenna 13 is mounted on the mast 13a so as to be movable up and down, and can be fixed at an optimal position by moving up and down the mast 13a using a winch 13b driven by the operation of an electric motor. There is.

This electromagnetic wave measuring device 10 can be easily maintained and inspected because the antenna 13 is exposed, but on the other hand, there are problems when using this electromagnetic wave measuring device 10 outdoors. That is,
If the antenna 13 is placed outdoors as it is, it will be directly exposed to wind and rain, direct sunlight, or moisture, and as a result, the antenna 13 will rust or deform, making it impossible to always measure electromagnetic waves under constant conditions. In addition, on windy days and rainy days,
There may be cases where measurements cannot be taken during snowfall. This is completely unsuitable to the current situation where demand for this type of electromagnetic wave measurement work is increasing.

In short, this conventional electromagnetic wave measuring device 10:
It was developed solely for indoor use, and is not suitable for use outdoors in so-called open sites.As mentioned above, this electromagnetic wave measurement system is not suitable for use in the current situation where relatively large electromagnetic wave measurement equipment is required. The device 10 cannot be used as is as an outdoor device.

(Object of the Invention) The present invention has been made in view of the above-mentioned circumstances, and its purpose is to enable easy measurement and to provide accurate and objective measurement results. The object of the present invention is to provide an electromagnetic wave measurement device that can always maintain a constant electromagnetic wave measurement environment so as to obtain such accurate and objective measurement results, and that can be constructed at an extremely low cost. .

Another object of the present invention is to protect the measuring antenna in this type of electromagnetic wave measuring device from the adverse effects of wind and rain.

Furthermore, another object of the present invention is to enable the roof portion of a completed electromagnetic wave measuring device to be easily replaced.

(Structure of the Invention) In order to achieve the above object, the gist of the present invention is to provide a device under test and an antenna that captures electromagnetic waves from the device under test, and measure the electromagnetic waves from the device under test. In the electromagnetic wave measuring device, the device to be measured and the antenna are airtightly covered with an air tent made of a flexible non-metallic material to form a measurement space, and pressurized air is supplied into the air tent. An electromagnetic wave measuring device characterized by being equipped with a blower.

In short, an object of the present invention is to form a measurement space in which the device under test and the antenna are housed by covering the device under test and an antenna that captures electromagnetic waves from the device under test with an air tent. By keeping the electromagnetic environment in the measurement space under stable conditions, it is possible to easily measure electromagnetic waves in a stable condition, and the measured results are objective. The purpose is to make it have the following.

(Example) An electromagnetic wave measuring device according to the present invention will be described below with reference to the drawings.

FIG. 2 shows a schematic configuration diagram of an electromagnetic wave measuring device 100 that embodies the electromagnetic wave measuring method according to the present invention. This electromagnetic wave measurement device 100 includes a measurement work chamber 20, an airtight adjustment chamber 30 disposed on the side of the measurement work chamber 20, and a blower 40. Further, a turntable 50 is installed on a part of the ceiling of the measurement work room 20, and an antenna 70 for electromagnetic wave measurement is installed on the measurement work room 20 at a position approximately 3 to 30 meters away from the turntable 50. It is being And these turntables 5
0 and the antenna 70 are hermetically covered by an air tent 80.

The measurement work room 20 has a size that allows a person to stand there and perform measurement work, and is provided with an electromagnetic wave measuring device 60 connected to an antenna 70.

The airtight adjustment room 30 is a room that communicates with the inside of the measurement work room 20 via a double door, and is designed to prevent the pressure inside the air tent 80 from decreasing when workers enter and exit. The blower 40 supplies air at a predetermined pressure into the air tent 80, and the temperature and pressure of the supplied air can be adjusted as necessary. Thereby, in the measurement space 100a formed by the air tent 80, not only the pressure but also the temperature and humidity of the air are always kept constant as necessary. Note that the conventional turntable 50 and antenna 70 were used as they were. In the electromagnetic wave measuring device 100 configured as described above,
Since the inside of the measurement space 100a is isolated from the outside by the air tent 80 and is always kept under constant conditions, the external conditions of the electromagnetic wave measurement device 100 may vary, such as whether it is under strong winds, raining, or snowing. The device under test W
It is possible to measure electromagnetic waves emitted from a device under constant conditions.

In the measurement work room 20, there are figures 3 to 8.
As shown in the figure, not only the electromagnetic wave measuring device 60 but also various devices necessary to measure the electromagnetic waves from the device under test W are installed, so that the worker does not have to enter the measurement space 100a. Moko measurement work room 2
Various tasks can be performed within the facility by remote control. Note that a staircase 21 is provided so that workers can enter and exit from the measurement work chamber 20 upwardly. Further, an elevator device (not shown) is installed in this measurement work room 20, and the base plate 22 of this elevator device can be raised into the measurement space 100a, as shown in FIG. , made of conductive material. Furthermore, the upper surface of the roof of this measurement work room 20 is coated with a conductive material to provide a floor surface 100b of the measurement space 100a.
This makes the floor surface 100b of the measurement space 100a a uniform reflective surface for electromagnetic waves.

As described above, the airtight adjustment chamber 30 communicates with the inside of the measurement work chamber 20 through the double door, and in this embodiment, the blower 40 is disposed within the chamber. Air at a predetermined pressure is supplied from this blower 40 into the measurement space 100a.
Note that the pressure air from the blower 40 may be fed into the measurement space 100a after adjusting its temperature and humidity to predetermined values as necessary. Additionally, an air compressor (not shown) is disposed in the airtight adjustment chamber 30 for supplying compressed air (approximately 5 kgf/cm ² ) to drive the turntable 50 and the winch 72 of the antenna 70, which will be described later. . Note that the airtight adjustment chamber 30 is electromagnetically shielded as necessary so that electromagnetic waves generated from each device inside the chamber do not enter the measurement space 100a. turntable 5
0, as shown in FIG. 5, is arranged near the base plate 22 of the above-mentioned elevator system. Further, the turntable 50 is rotated by an air motor or an air cylinder 52 disposed below the turntable 50, and is stopped at an appropriate position. The compressed air that drives this air motor or air cylinder 52 is supplied to the airtight adjustment chamber 30 as described above.
Powered by an internal air compressor. Furthermore, a non-conductive table 5 having a height of about 1 m is placed on the turntable 50, and when the device under test W is used on a desk, a non-conductive table 5 is placed on the table 51. Measurement is performed with the measuring device W placed thereon.

The antenna 70 in this embodiment is a calibrated, tuned, half-wavelength die-ball antenna capable of measuring both horizontal and vertical polarization. Note that this antenna 70 may be of any type as long as its specifications, calibration values, etc. can be clearly proven. Also, like the conventional antenna, this antenna 70 is mounted on a support column 71 so that it can be raised and lowered, and the operation of a winch 72 causes the antenna 70 to move up and down.
Move up and down on 1. (See Figure 2) The range of this vertical movement is between 2 and 6 m. The winch 72 is equipped with an air motor, and by supplying compressed air from an air compressor in the airtight adjustment chamber 30 to the air motor, the winch 72 is selectively operated as appropriate. Furthermore, the support 7 of this antenna 70
1 is movable back and forth with respect to the turntable 50, as shown in FIG. 5, and its maximum separation distance is approximately 30 m.

As shown in FIGS. 3 and 4, the air tent 80 is formed into a substantially spherical shape, and its diameter is the same as that between the device under test W on the turntable 50 and the antenna 7.
It is set so that the distance between 0 and 0 is approximately 3 to 30 meters. The air tent 80 is made by coating a woven fabric with a synthetic resin such as vinyl chloride to form a non-conductive sheet, cutting this sheet into a predetermined shape, and pasting them together using high frequency welding or the like to create an airtight seal. It was formed.

As shown in FIGS. 3 and 8, this air tent 80 has a rope 81 made of a non-conductive material fixed to the entire circumference of its lower end.
The air tent 80 holding the rope 81 is reinforced by fixing a reinforcing tape 83 to the outer surface thereof. Air tent 80 formed in this way
is fixed by bolts and nuts 85 to a mounting angle 84 fixed on the floor 100b of the measurement space 100a using a sample sheet 82 arranged on the inner surface of the air tent 80. In this case, the rope 81 is located below the sample sheet 82, and the sample sheet 82 comes into contact with the attachment angle 84, thereby fixing the main body of the air tent 80 to the floor surface 100b. At the same time, at the lower end of the air tent 80, airtightness is maintained between the inside and outside of the air tent 80. Further, in this air tent 80, as shown in FIGS. 6 and 7, the outer periphery of the air tent 80 is covered with a protective canvas 86. The protective kinbus 86 is made of a non-conductive canvas cloth, and has a reinforcing rope 87 fixed all around its lower edge, and a plurality of cloth fixing tapes 88 attached to its lower end. These fixing tapes 88
is connected to a non-conductive rope 88a, and the lower end of this rope 88a is connected to the measurement space 100a.
It is connected to a hook 89 fixed on the floor surface 100b. Thereby, the protective canvas 86 protects the air tent 80 from strong winds and the like. As described above, all of the members constituting the air tent 80 located above the floor surface 100b of the measurement space 100a are made of non-conductive material so as not to reflect electromagnetic waves.

Next, the electromagnetic wave measuring device 1 configured as described above will be described.
00, the case where electromagnetic waves from the device under test W are measured will be explained. First, the blower 40 is operated to supply pressurized air adjusted to a predetermined state into the measurement space 100a, thereby holding the air tent 80 in a predetermined shape (spherical shape shown in FIG. 3). In addition,
When the external condition of this electromagnetic wave measurement device 100 is normal, the pressure inside the air tent 80 is adjusted to 50 mmAq/cm ² , and under strong winds, the air tent 80
The pressure inside is adjusted to 100mmAq/ ^cm2 . In this state, the equipment W to be measured is carried into the measurement space 100a from the measurement work room 20 using the elevator system, and is placed on the turntable 50. and,
The device under test W on the turntable 50 is rotated and the height of the antenna 70 is adjusted to find the maximum value indicated by the electromagnetic wave measuring device 60. The value measured in this way is determined as the electromagnetic wave being generated by the device under test W. For the measurement itself, the conventional method is used as is.

Note that if the air tent 80 and the protective canvas 86 deteriorate due to long-term use of the electromagnetic wave measuring device 100, only the air tent 80 and the protective canvas 86 are replaced.

(Effects) According to the present invention configured as described above, the following effects can be obtained. That is, (a) since the measurement space 100a can be configured by the air tent 80, various conditions required for the measurement space 100a can be easily satisfied;
Therefore, a relatively large electromagnetic wave measuring device 100 can be formed without being limited by the distance between the device under test W and the antenna 70.

(b) Since the measurement space 100a is formed by the air tent 80 and pressured air with adjusted temperature and humidity is supplied into the air tent 80 as necessary, the measurement conditions within the measurement space 100a are always kept constant. As a result, electromagnetic wave measurement results can always be objective.

(c) Since the device under test W and the antenna 70 are housed in the air tent 80, the antenna 70, which is frequently used, can be protected from wind and rain, thereby making it possible to always obtain stable measurement results. At the same time, it is possible to provide objectivity to the measurement results.

(d) Since the winch 72 of the turntable 50 and the antenna 70 is operated by compressed air from an air compressor placed in the airtight adjustment chamber 30, the turntable 50 can be
Compared to the case where the winch 72 is driven by an electric motor, it is possible to prevent noise from being generated from each operating device other than the device to be measured, and more accurate and objective measurement results can be obtained.

(e) In relation to the effect of (c) above, the measurement space 100a
Since it is covered with an air tent 80, a large measurement space 100a that does not require any measures against reflected electromagnetic waves can be constructed extremely easily, and this type of electromagnetic wave measuring device, which has conventionally been relatively expensive, can be provided at a low cost. can do.

(F) Furthermore, since the measurement space 100a is covered with the air tent 80, electromagnetic waves can be measured completely unaffected by the weather, and the demand for this type of electromagnetic wave measurement work has been increasing recently. can respond immediately.

(G) Since the air tent 80 and the protective canvas 86 are fixed to the upper surface of the measurement work chamber 20 at their lower ends, even if the air tent 80 and the protective canvas 86 deteriorate due to long-term use, they can be easily replaced. be able to.

(Summary) As described in detail above, according to the electromagnetic wave measuring device according to the present invention, as exemplified in the above embodiment, a device under test and an antenna that captures electromagnetic waves from the device under test are arranged. , an electromagnetic wave measuring device that measures electromagnetic waves from the device under test,
The device under test and the antenna are airtightly covered with an air tent made of a flexible non-metallic material to form a measurement space, and a blower is provided for supplying pressurized air into the air tent. To provide an electromagnetic wave measuring device which is particularly characterized in that it can always maintain a constant electromagnetic wave measurement environment so as to obtain objective measurement results, and which can be constructed at an extremely low cost. In addition to being able to protect the measuring antenna of this type of electromagnetic wave measuring device from the adverse effects of wind and rain, etc., it is also possible to easily replace the part that serves as the roof of the completed electromagnetic wave measuring device. I can do it.

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing a conventional electromagnetic wave measuring device, FIG. 2 is a schematic front view of an electromagnetic wave measuring device according to the present invention, FIG. 3 is a front view showing an electromagnetic wave measuring device according to the present invention, and FIG. is the same side view, FIG. 5 is a plan view taken along the - line in FIG. 3, FIG. 6 is a partially enlarged vertical cross-sectional view of the line in FIG. 3, and FIG. 7 shows a part of the protective canvas. The front view and FIG. 8 are partially enlarged longitudinal sectional views taken along the - line in FIG. 6. Explanation of symbols, 10... Conventional electromagnetic wave measuring device,
100... Electromagnetic wave measurement device, 100a... Measurement space, 20... Measurement work room, 30... Airtight adjustment room,
40...Blower, 50...Turntable, 60
...Electromagnetic wave measuring device, 70...Antenna, 80...
Air tent, W...Device to be measured.

Claims (1)

[Claims] 1. In an electromagnetic wave measuring device that measures electromagnetic waves from the device under test, which is equipped with a device under test and an antenna that captures electromagnetic waves from the device under test,
The device under test and the antenna are airtightly covered with an air tent made of a flexible non-metallic material to form a measurement space, and a blower is provided for supplying pressurized air into the air tent. An electromagnetic wave measuring device characterized by: