JPH077033B2 - Electromagnetic interference rejection capability measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring electromagnetic wave interference elimination capability of electronic equipment and the like.

[0002]

2. Description of the Related Art In recent years, electromagnetic wave noise generated from electronic devices such as office automation equipment and personal computers causes troubles in reception of televisions and radios and causes troubles such as malfunctions of computers and automatic vehicles. The so-called electromagnetic interference has become a serious social problem. Therefore, we have taken countermeasures against electromagnetic interference in electronic devices and measured their ability to eliminate electromagnetic interference.

Conventionally, an object to be measured such as an electronic device is put in a TEM cell for this measurement, and high frequency power is applied to the TEM cell to generate an electric field in the cell to change the frequency and the high frequency power. The electric field strength in the TEM cell at the time when the DUT starts to cause reception failure or malfunction is measured.

More specifically, as shown in FIG. 1, a TEM cell (1) has a hollow body (2) having a conductive cross section, and both ends (3) and (4) of which are narrowed into a quadrangular pyramid shape. A plate-shaped conductor (5) is provided at the center. A signal generator (6) for transmitting a high frequency power signal is connected to the input end of the TEM cell (1), and a dummy load (7) is connected to the output end.

When a high frequency is output from the signal generator (6), the electromagnetic wave (8) travels in the TEM cell (1) in a direction parallel to the central conductor (5), and an electric field (9) in a direction perpendicular thereto. ) Is generated, and an electric field in a fixed direction is applied to the DUT (10). Therefore, it is only possible to measure the ability to eliminate electromagnetic interference in an electric field in a fixed direction.

In reality, electromagnetic waves propagate in all directions, and electric fields also occur in all directions. Therefore, it is necessary to investigate the ability of the device under test to eliminate interference against electric fields from all directions. For this reason, the orientation of the object to be measured is changed, but it is very troublesome.

[0007]

In view of the above, the present invention has been made.
A device that can perturb the direction of radio waves in a TEM cell without changing the orientation of the DUT and orient the electric field in all directions, thereby examining the influence of the electric field in all directions on the DUT. Is to provide.

[0008]

Therefore, in the present invention, the fan is rotated in the TEM cell to disturb the radio wave condition at the place where the object to be measured is placed, and the electric field is directed in all directions.

[0009]

EXAMPLE A TEM cell (11) shown in FIG. 2 is also similar to the conventional one shown in FIG. 1, and both ends (13) and (14) of a hollow body (12) having a conductive cross section have a quadrangular pyramid shape. It is squeezed and has a plate-shaped conductor (15) at the center, which is an extremely thick coaxial cable. A signal generator (16) for transmitting a high-frequency power signal is connected to the input end of the TEM cell (11), and a dummy load (17) is connected to the output end. Further, an appropriate number of fans (18) for electromagnetic wave disturbance are arranged in the TEM cell (11), and these fans are connected to the TEM through the shaft (19).
It is rotated by a motor (20) outside the cell. The fan (18) is formed of a conductive material such as aluminum or copper,
The shaft 19 is made of a non-conductive material such as Bakelite.

When the frequency is set and the high frequency output value is set by the signal generator (16) and is output, the TEM cell (1
An electric field (9) in the direction orthogonal to the electromagnetic wave (8) in the direction parallel to the central conductor (15) is generated in 1). When the fan (18) is rotated by the motor (20), the electromagnetic wave (8) traveling in a fixed direction in the TEM cell (11) is diffusely reflected. At this time, the measured object (1
The radio wave condition of the place where (0) is placed is the disturbance state (21), and an electric field (22) in all directions is generated. Then, DUT (10)
By measuring the electric field strength that causes a malfunction, the ability to eliminate interference by electromagnetic waves is measured.

[0011]

According to the present invention, with the above configuration, it is possible to easily measure the influence of an object to be measured, which is received from an electric field in all directions, and hence the ability to eliminate interference by electromagnetic waves in all directions.

[Brief description of drawings]

FIG. 1 is a block diagram showing a conventional measuring apparatus for electromagnetic wave interference elimination capability and its operating state.

FIG. 2 is a block diagram showing an apparatus for measuring electromagnetic wave interference elimination capability according to an embodiment of the present invention.

FIG. 3 is a block diagram showing an operating state of the apparatus of FIG.

[Explanation of symbols]

1 TEM cell 5 conductor 6 signal generator 7
Dummy load 8 Electromagnetic wave 9 Electric field 10 DUT 11
TEM cell 15 conductor 16 signal generator 1
7 Dummy load 18 Fan 19 Shaft 20 Motor 21 Electromagnetic wave 22 Electric field

Claims (2)

[Claims] 1. A TEM cell capable of accommodating an object to be measured such as an electronic device and generating an electric field inside when a high frequency power is applied, and a high frequency power signal is sent to the TEM cell to generate an electric field. A device for measuring electromagnetic wave interference, comprising: a signal generator for controlling the electromagnetic interference and a fan provided in the TEM cell for stirring an electric field and directing the electric field in all directions. 2. An apparatus for measuring electromagnetic wave interference elimination ability according to claim 1, wherein said fan is driven via a shaft by a motor provided outside the TEM cell.