JPH0827317B2 - Method and device for measuring unnecessary electromagnetic waves - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a measuring method and a measuring apparatus for an interfering radio wave or an unnecessary electromagnetic wave generated from a device under test such as an electronic device.

B. Summary of the Invention The present invention is a method for measuring an unwanted electromagnetic wave generated from a device under test, in which the function of the measuring device is set to a max hold state, and the receiving antenna of the device is measured while continuously rotating the device under test at high speed. By moving at a low speed, the maximum radiation level from the device under test can be easily measured in a short time and with high reliability.

C. Conventional technology Measurement of interfering radio waves or unwanted electromagnetic waves generated from electronic devices such as television receivers is stipulated by, for example, international standards. In this measurement, the interference radio wave radiated from the above-mentioned device under test is received by the antenna arranged at a certain distance (for example, 3m, 10m, 30m, etc.) from the device under test such as electromagnetic equipment, and the interference Measure the level with a measuring instrument. At this time, it is necessary to rotate the device under test by 360 ° and move the antenna vertically for 1 to 4 m or 1 to 6 m to detect the maximum radiation level. That is, when searching for this maximum radiation level, there are two factors: (1) the rotation angle of the device under test, (2) the height of the receiving antenna, and (3) the frequency of the interference wave radiated from the device under test. , And these three factors change the reception interference level. For this reason, conventionally, it has been necessary to change the combination of the above three factors and perform adjustment so that the reception interference level is maximized, and then perform the measurement.

D. Problems to be Solved by the Invention The above-described conventional method for measuring an interfering radio wave (unwanted electromagnetic wave) has the following drawbacks. That is, not only is it difficult for anyone to perform the measurement because experience and skill are required for the measurement, but also a person skilled in the measurement needs a measurement time of 4 to 5 hours per device to be measured. In addition, the measured value may differ depending on the measurer, for example, when the approval test is unsuitable even though it was OK at the design stage,
There is a possibility that a situation may occur in which the product cannot be taken in time for the product due to a lack of sufficient time for measures such as design changes.

Therefore, it is desired to automate the measurement of the jamming radio waves, for example, in Japanese Patent Application No. 62-13467, a gear is attached to the rotating shaft of the antenna to engage the toothed belt,
An antenna driving device is disclosed in which the vertical axis of the belt rotates the polarization axis of the antenna and a stopper for rotation regulation is provided. However, in the conventional automatic measurement, only partial automation is performed, and under the present circumstances, automatic measurement combining the above three factors is not realized.

The present invention has been made in view of such circumstances, and provides an unnecessary electromagnetic wave measuring method and a measuring device that can automatically measure an unnecessary electromagnetic wave with high accuracy and that the time required for the measurement is short. With the goal.

E. Means for Solving Problems The unnecessary electromagnetic wave measuring method according to the present invention, in order to solve the above problems, receives an electromagnetic wave generated from a device under test with an antenna, and based on the received signal. In the unnecessary electromagnetic wave measuring method in which the maximum radiation level of unnecessary electromagnetic waves is measured with a measuring instrument, the entire measurement band is divided into a plurality of bands, and the divided plural bands are sequentially switched and selected. In the max hold state in which the maximum value of the reception level is held, the antenna is moved at a low speed between the lowest position and the highest position while rotating the turntable on which the device under test is installed at high speed, and the selected While performing frequency sweep in each band, measure the reception level at the receiver, hold the maximum reception level for each of a plurality of preset frequency points until the measurement is completed, The polarization plane of the antenna is rotated approximately 90 degrees to perform the measurement of all the band of the horizontal, vertical in both the plane of polarization of the antenna,
The feature is that the rotation of the turntable is stopped when the measurement is completed.

Further, in order to solve the above-mentioned problems, the unnecessary electromagnetic wave measuring device according to the present invention receives the electromagnetic wave generated from the device to be measured by the antenna, and determines the maximum emission level of the unnecessary electromagnetic wave based on the received signal. In a device for measuring unnecessary electromagnetic waves measured by a measuring instrument, a turntable for rotating and driving the device under test and the antenna vertically moving up and down with a predetermined distance from the installation position of the device under test. An antenna elevator to be driven, a measuring instrument connected to the antenna and having a max hold function for holding a maximum value of a reception level, an operation of the turntable, the antenna elevator and the measuring instrument and controlling the entire measurement band. Divide into multiple bands, switch and select these bands sequentially, and perform frequency sweep in each selected band,
A controller that rotates the polarization plane of the antenna by approximately 90 ° to measure all bands of both the horizontal and vertical polarization planes of the antenna is provided, and by operating the controller, the turn is automatically performed. It is characterized in that the table is continuously rotated at a high speed, the antenna is moved at a low speed, and the measuring device is put in a max hold state.

F. Working The function of the measuring instrument is set to the max hold state, and by moving the antenna at a low speed while rotating the device under test at a high speed, it is possible to completely automate the measurement of unnecessary electromagnetic waves, and the measurement is simple and reliable. The cost can be increased and the measurement time can be shortened.

G. Examples Hereinafter, examples of the method and apparatus for measuring an unnecessary electromagnetic wave according to the present invention will be described with reference to the drawings.

FIG. 1 is a diagram schematically showing a measuring system which is a specific example of an unnecessary electromagnetic wave measuring apparatus used in a method for measuring an unnecessary electromagnetic wave according to an embodiment of the present invention, and FIG. 2 shows an operation procedure of the embodiment. It is a flowchart shown.

First, in FIG. 1, an equipment table 2 on which a device under test 1 such as a television receiver is placed is installed on a turntable 4 which is rotationally driven by a motor 3. An antenna elevator 7 for vertically moving the antenna 5 by a motor 6 is installed at a predetermined distance, for example, 3 m (or 10 m, 30 m, etc.) from the position where the device to be measured 1 is arranged. A measuring instrument 8 is connected to the antenna 5 so that the antenna 5 and the measuring instrument 8 measure the electric field strength (so-called interference level) of an unwanted electromagnetic wave or an interfering wave radiated from the device under test 1. It has become.
Further, the operation of the device under test 1, the turntable 4, the antenna elevator 7 and the measuring device 8 is controlled by a controller 9 using a so-called microprocessor or the like.

Prior to starting the measurement of the unwanted electromagnetic wave from the device under test 1 using such a measuring system, the device under test 1 is placed on the equipment table 2 on the turntable 4, and the power supply for the device 1 is set. Turn on. Next, by operating the controller 9, the operation control of the turntable 4, the antenna elevator 7, and the measuring device 8 is sequentially executed according to the flowchart of FIG. 2, and the unnecessary electromagnetic wave is automatically measured.

That is, when the automatic measurement of the unnecessary electromagnetic waves is started, the position of the antenna 5 is initialized in step S1 of FIG. 2, and then the measurement band is selected in step S2,
In step S3, the function of the measuring device 8 is set to the max hold state, and in step S4, the turntable 4 starts rotating. Here, the initial setting of the antenna position in step S1 is to position the antenna 5 at a minimum height of 1 m, for example, and during the measurement operation described later, move the antenna 5 from this minimum position to a height of 4 m (or 6m) is driven up to the highest position at a low speed, then is driven downward from the highest position to the lowest position, and this is repeated sequentially. The selection of the measurement band in step S2 means that the entire measurement band from 30 MHz to 1000 MHz (= 1 GHz) is, for example, 5 bands, that is, 30 MHz to 80 MHz, 80 MHz to 150 MHz, 150 MHz to 300 MHz. When performing measurement by dividing into 300M Hz to 500M Hz and 500M Hz to 1000M Hz (= 1G Hz), the band to be measured from now on is selected sequentially from the above. During measurement, the interference level is measured while performing frequency sweep within this selected band. The frequency sweep cycle at this time is, for example, 50 msec to 80 msec. The max hold function setting in step S3 above is a state in which the maximum value of the disturbance level is held for each of a plurality of preset frequency points (for example, 1002 points) within the selected measurement band. In this state, the maximum disturbance level at each frequency point is held until the measurement for the one band is completed. Next, the rotation of the turntable 4 started in step S4 is relatively high, and the time required for one rotation of 360 ° is 3 seconds, that is, 20 rotations / minute.

Next, in step S5, it is determined whether or not to raise the antenna ascending / descending operation. When the current position of the antenna 5 is the lowest position, the determination result is YES, and the process proceeds to the next step S6. The antenna raising operation is executed.
In the next step S7, it is determined whether or not the antenna 5 has reached the highest position. If NO, the process returns to step S6 to continue the antenna raising operation, and if YES, the process proceeds to step S8. The antenna ascending / descending speed in this case is set relatively low, for example, 5 cm / sec. As described above, while rotating the turntable 4 at a high speed, the antenna 5 is moved at a low speed once between the lowest position and the highest position in one direction, thereby
The measurement for one band ends.

By the way, the height of the antenna 5 is, for example, each position a, b, and c in FIG. 1, and the angle of the device under test 1 (rotation angle of the turntable 4) at each time is, for example, 100.
When the angle is 150 °, 300 °, and 300 °, the spectrum of each disturbance level appears as shown in FIGS. 3A, 3B, and 3C, respectively. In these FIGS. 3A to 3C, the frequencies f _{1 to} f ₆ at which a predetermined level or more is obtained are frequencies that are integral multiples of the fundamental frequency such as the fundamental clock frequency and the internal oscillation frequency in the device under test 1 (so-called harmonic Frequency), which is almost fixed within one of the above measurement bands, but the levels at these frequencies f _{1 to} f ₆ are as shown in FIGS. 3A to 3C. , The height of the antenna 5 and the angle of the device under test 1 (the rotation angle of the turntable 4). Therefore, conventionally, the height of the antenna 5 and the rotation angle of the turntable 4 are changed for each frequency of the interference spectrum to find the maximum interference level, which is complicated and takes a long time.
In the embodiment of the present invention, the function of the measuring device 8 is set to the max hold state, and the antenna 5 is moved at a low speed in the vertical direction while the turntable 4 is rotated at a high speed. maximum interference level at f ₁ ~f ₆ is displayed, for example, fourth respectively held as shown in FIG.

As described above, when the measurement for one measurement band is completed, the process proceeds to step S8, the rotation of the turntable 4 is stopped, and at the next step S9, the maximum at each frequency point as shown in FIG. The disturbance level data is sent to a data processing device, a storage device, or the like.

In the next step S10, the above 5
It is determined whether or not the measurement has been completed for all of the one measurement band. If NO, the process returns to step S2 to switch and select the next measurement band. The following operation is similar to the operation after step S2 described above, but if the antenna 5 has reached the highest position at the time when the measurement of one band is completed, it is determined as NO in step 5,
In step S11, the antenna lowering operation is executed, and in the next step S12, the antenna lowering operation is continued until it is determined that the antenna position is the lowest. When the antenna 5 reaches the lowest position, the process proceeds to step S8 and the same operation as described above is performed.

When YES is determined in step S10, that is, when the measurement of all bands to be measured is completed,
In step S13, the plane of polarization of the antenna 5 is rotated 90 °. The switching drive of the antenna polarization plane may be performed using, for example, the antenna drive device disclosed in Japanese Patent Application No. 62-13467 previously proposed by the applicant of the present application. Next steps
In S14, it is determined whether or not the measurement of the entire band for both the horizontal and vertical polarization planes of the antenna 5 is completed. If NO, the process returns to step S2, and if YES, such automatic measurement is performed. Complete the operation.

According to the above-mentioned measurement method, for example, all the measurement is completed in about 40 minutes, so that it takes about 1/8 to 1/10 of the measurement time compared with the conventional method that required at least several hours. Can be shortened. Moreover, the number of measurement frequency points is larger than in the past, and the accuracy is high and the reliability is excellent.

Note that the present invention is not limited to the above example, and for example, the above measurement band is from the above to (30M Hz to 300M Hz) and from to (300M Hz to 10MHz).
00M Hz), and after performing all measurements with the plane of polarization of the above antenna horizontal / vertical in the bands from to, all the same measurements in the bands from to may be performed. . Further, it is needless to say that the boundary frequency and bandwidth of each band are not limited to the above example. In addition, various changes can be made without departing from the spirit of the present invention.

H. Effect of the Invention According to the unnecessary electromagnetic wave measuring method and the measuring apparatus according to the present invention, regarding the factor of the rotation angle of the device under test, by continuously rotating the device under test at a high speed, Regarding the factor, by moving the antenna up and down at a low speed, and further regarding the factor of the frequency of the interfering wave radiated from the device under test, by setting the function of the measuring instrument to the max hold state and sweeping the measuring frequency, Almost all combinations of the respective factors can be continuously obtained, and the measurement of unwanted electromagnetic waves can be fully automated. Therefore, the measurement can be easily performed in a short time, and the measurement with high accuracy and reliability can be obtained. Further, in all the bands to be measured, the polarization plane of the antenna is rotated by about 90 ° to measure both the horizontal and vertical polarization planes of the antenna, so that the measurement accuracy can be further improved.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a measuring system used in an embodiment of a method for measuring an unnecessary electromagnetic wave according to the present invention, FIG. 2 is a flow chart for explaining a measuring operation procedure of the embodiment, and FIG. A to C are the antenna height positions a to c in FIG.
FIG. 4 is a characteristic diagram showing the spectrum of the interference level in FIG. 4, and FIG. 4 is a characteristic diagram showing the spectrum of the interference level when the measuring instrument is in the max hold state. 1 ... Device under test 4 ... Turntable 5 ... Antenna 7 ... Antenna elevator 8 ... Measuring device 9 ... Controller

Claims (2)

[Claims] 1. An unnecessary electromagnetic wave measuring method in which an electromagnetic wave generated from a device to be measured is received by an antenna, and the maximum emission level of the unnecessary electromagnetic wave is measured by a measuring device based on the received signal. And select the divided multiple bands sequentially, and set the measuring device to the max hold state that holds the maximum value of the reception level, and set the turntable on which the device under test is installed at high speed. While rotating at, move the antenna at a low speed between the lowest position and the highest position, measure the reception level at the receiver while performing frequency sweep in each of the selected bands, and in advance until the measurement is completed. The maximum reception level for each of the set multiple frequency points is maintained, and the polarization plane of the antenna is rotated by approximately 90 ° to determine the horizontal and vertical polarization planes of the antenna. A method for measuring unnecessary electromagnetic waves, which comprises measuring all of the above bands and stopping the rotation of the turntable when the measurement is completed. 2. An unnecessary electromagnetic wave measuring device for receiving an electromagnetic wave generated from a device under test with an antenna and measuring the maximum emission level of the unnecessary electromagnetic wave with a measuring device based on the received signal. A turntable for rotationally driving the device under test, an antenna elevator for vertically moving the antenna at a predetermined distance from the position where the device under test is installed, and a reception level connected to the antenna and for receiving A measuring instrument having a max hold function for holding the maximum value, controlling the operation of the turntable, the antenna elevator, and the measuring instrument, dividing the entire measurement band into a plurality of bands, and sequentially switching and selecting these bands. A frequency sweep is performed within each selected band, and the plane of polarization of the antenna is rotated by approximately 90 °, and the horizontal and vertical It is equipped with a controller that measures all bands in the plane of polarization, and by operating the controller, the turntable is automatically continuously rotated at high speed, the antenna is moved at low speed, and the measuring instrument is maximally moved. A device for measuring unnecessary electromagnetic waves that is placed in a hold state.