JP2006010518A - Electromagnetic interfering wave measuring device and electromagnetic interfering wave measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic interfering wave measuring device capable of shortening EMI measure time. <P>SOLUTION: Only frequency band where noise is generated is extracted with a frequency selection means constituted of a band-pass filter 41a connected with an antenna 24, and a square wave is formed for the extracted noise signal. The square wave is input in an indication means synchroscope 41b and a trigger is applied to the square wave and noise is detected from the input obtained by moving a near magnetic probe 41c nearby the machine under test 50. Thus, from the position of the near magnetic probe 41c during the noise detection, identifying noise source becomes possible. In this manner, effective noise detection becomes possible and identifying time of noise source is shortened compared with conventional identification of generation source by estimation, and so shortening of noise measure time becomes possible. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electromagnetic interference wave measuring apparatus and an electromagnetic interference wave measuring method, and more particularly, to an electromagnetic interference wave measuring apparatus and an electromagnetic interference wave measuring method that facilitate noise countermeasures.

Conventionally, as an electromagnetic interference measurement device,
Japanese Patent Laid-Open No. 2002-257882 discloses a technique for improving the reliability of electromagnetic interference measurement by performing far-field evaluation with high accuracy by estimating a far-field pattern.
Japanese Patent Laid-Open No. 2002-277499 discloses a technique for sequentially displaying a magnetic field strength distribution of a specific frequency and accurately displaying a magnetic field strength distribution whose frequency dynamically changes.
Japanese Patent Application Laid-Open No. 10-185974 discloses a technique capable of measuring at what timing noise is generated at a measurement point by performing measurement by executing sequence processing.
In general, a noise level and a peak frequency are given to noise measured by a conventional electromagnetic interference wave measuring apparatus.
JP 2002-257882 A JP 2002-277499 A Japanese Patent Laid-Open No. 10-185974

  Conventionally, in countermeasures against noise extracted by the electromagnetic interference measurement, the frequency obtained by the measurement is compared with the operating frequency in the internal circuit of the EUT, from which electrical circuit the frequency is generated, A countermeasure is taken against the noise by estimating how the signal propagates. However, almost all video display devices operate at the same signal frequency, and there is a problem that it is extremely difficult to specify the source by estimation.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electromagnetic interference wave measuring apparatus and an electromagnetic interference wave measuring method capable of shortening the countermeasure time for EMI noise.

In order to achieve the above object, the invention according to claim 2 comprises an antenna for capturing noise radiated from the UUT in a shape corresponding to the measurement frequency band and a measuring device for analyzing the signal input from the antenna. In the electromagnetic interference wave measuring device to be
A frequency selecting means for extracting a signal component of a predetermined frequency band connected to the antenna and capable of changing, and generating a trigger signal based on the signal component;
Display means for detecting and displaying the electrical signal synchronized with the trigger signal generated by the frequency selection means while inputting a predetermined electrical signal;
Noise source specifying means comprising a probe connected to the display means and outputting the electrical signal is provided.

In the invention according to claim 2 configured as described above, the noise source of the device under test is specified based on a given measurement result.
In order to extract only a noise component whose source is desired to be identified from an input signal in which signal components of various frequency bands are mixed, the frequency selection means is set to the frequency band.
Then, the input to the display means other than the frequency component set by the frequency selection means is limited for the input of the radiated electric field intensity from the EUT received by the antenna, and the timing and level of the noise component to be extracted Can be observed by the display means. For the noise component, a signal component is generated by an arbitrary trigger generation circuit or the like to generate a rectangular wave having the same timing and generation period as the noise component, and is used as a trigger signal for specifying the generation timing.

Here, the frequency selection means is not particularly limited as long as it has the function of a filter capable of extracting a specific frequency component such as a band pass filter. Further, when setting the specific frequency band, it may be adjusted and set by a variable resistor or a switch for selecting the frequency band.
In the display means, the input of the rectangular wave, which is noise, is input to a trigger input terminal or a channel input terminal provided in the display means to trigger the rectangular wave. Then, a trigger is applied to a signal input from another channel of the display means at the same time as the trigger signal when the trigger signal is synchronized with the trigger signal, and the input signal is displayed on the display unit. Become. The probe, which is the noise source specifying means connected to the display means, has a property of detecting various frequency components.

Therefore, simultaneously with the trigger signal, when the signal detected by the probe is moved to the display means by moving the vicinity of the device under test with the probe, the noise signal is input from the input signal in which various frequency components from the probe are mixed. Can be detected. The signal that can be observed on the display unit is a signal synchronized with the trigger signal and can be said to be noise.
Therefore, the position of the probe when noise is extracted as a result of signal detection by movement of the probe can be identified as the noise source and its vicinity in the machine under test.
The display means may be a spectrum analyzer, a digital oscilloscope, or the like as long as it can detect the generation of a component desired to be extracted from the input signal and display it on the provided display unit.

  The invention according to claim 3 is configured such that the probe in the noise source specifying means according to claim 2 is a narrow directivity probe.

In the invention according to claim 3 configured as described above, it is possible to specify the vicinity of the noise source on the device under test by the probe.
That is, in specifying the noise source, if a change in the electric field intensity in a narrow range such as a probe can be detected and output to the display means, the noise is generated when a desired signal component is present in the output. It can be specified near the source.
Here, the probe has to be moved on the machine under test, and the machine under test is greatly moved with respect to the probe, and the probe may move over a wide range. In such a case, first, a noise generation range is roughly extracted with an antenna or a near-field probe that can be easily detected over a wide range, and after narrowing down the above range, noise can be picked up in a narrower range within the extracted noise generation range. Pinpoint noise sources using a probe.
Further, the movement of the antenna or probe may be the entire device under test or a partial range of movement, and the moving means may be manual or automatic.

  According to a fourth aspect of the present invention, the display means according to any one of the first to third aspects includes a notification means for detecting and notifying the noise captured by the noise source specifying means.

  In the invention according to claim 4 configured as described above, when the trigger is set for the noise as described above and the probe as the noise source specifying means is moved and observed in the device under test. It is possible to notify the observer that the probe is located in the vicinity of the noise source by notifying means by displaying sound or light by inputting a frequency component synchronized with the trigger signal to the display means. Become.

According to a fifth aspect of the present invention, there is provided an electromagnetic interference wave comprising an antenna that captures noise radiated from a device under test in a shape corresponding to a measurement frequency band, and a measurement device for analyzing a signal input from the antenna. In the measuring device,
A frequency selection means for extracting a signal component of a predetermined frequency band connected to the antenna and capable of changing, and generating a trigger signal based on the signal component;
A noise source specifying means comprising a probe for capturing noise radiated from the device under test in the vicinity of the device under test;
Comparing means for inputting the electrical signal from the probe and inputting the trigger signal generated by the frequency selecting means, and comparing the presence or absence of both inputs;
And a notifying means for detecting and notifying the output signal of the comparing means.

In the invention according to claim 5 configured as described above, the rectangular wave output from the frequency selecting means and the frequency signal generated from the device under test are captured by the probe as the noise source specifying means. A signal is input to the comparison means. The comparison means monitors both inputs and outputs a predetermined signal depending on the presence / absence of inputs from both.
As the comparison means, any means capable of determining the presence or absence of two inputs may be used. For example, when an AND circuit is used, AND is performed on the two inputs from the rectangular wave and the probe, and inputs from both are present. Outputs H, and when there is no input from either or both, it can be set to L output. Thus, by taking the AND of the two inputs, the generation of a signal having the same timing and generation period as the noise signal that is the rectangular wave with respect to the input signal from the probe is detected, and the detection result is A signal can be output.
The informing means informs the observer that the noise source specifying device is located near the noise source by the informing means by displaying sound or light based on the output signal from the comparing means.
As the notification means, the output signal from the comparison means can be input to the LED drive circuit to light the LED light, or the detection of noise can be notified to the outside by sound when the piezoelectric buzzer is turned on / off. Is possible.

Here, the first aspect includes an antenna that captures noise radiated from the device under test in a shape corresponding to the measurement frequency band, and a measurement device that analyzes a signal input from the antenna. In an electromagnetic interference measuring apparatus that measures noise radiated from a UUT placed at a distance of, and that gives the noise level and peak frequency as a result,
A trigger signal is generated based on the signal component extracted by adjusting the frequency band of the noise with a variable resistor or frequency selection switch using a bandpass filter that extracts a signal component of a predetermined frequency band that can be connected to the antenna and can be changed. Frequency selection means to perform,
Display means by a synchroscope for inputting and outputting a predetermined electric signal and detecting and displaying the electric signal synchronized with the trigger signal generated by the frequency selecting means;
And a noise source specifying means comprising a near-field probe connected to the synchroscope and outputting the electrical signal, or a probe of the synchroscope, and claim 1 is a configuration according to claims 2 to 4. It can be said that the means and action are integrated.

  The method of specifying the noise source as described above is not necessarily limited to a substantial apparatus, and is effective as a method invention as in the invention described in claim 6. In addition, the electromagnetic interference wave measuring device described above may exist alone or may be used in a state where it is incorporated in a certain device. The idea of the invention includes various aspects. Further, it can be changed as appropriate, such as software or hardware.

As described above, according to the first, second, and sixth aspects of the invention, it is possible to significantly reduce the time for specifying the position of the noise source by EMI measurement.
According to the third aspect of the present invention, it is possible to pinpoint the position that is the noise source on the machine under test.
According to the fourth aspect of the present invention, the time required to specify the position of the noise source can be shortened by notifying the observer of the position of the noise source with sound, light, or the like, and narrowing down the rough position quickly.
According to the fifth aspect of the present invention, the time required can be shortened by notifying the observer of the position of the noise source only by sound or light.

Hereinafter, embodiments of the present invention will be described in the following order.
(1) Configuration of electromagnetic interference measurement device:
(2) Explanation of the premise EMI measuring device:
(3) Noise source identification by probe:
(4) Modification:
(5) Summary:

(1) Configuration of electromagnetic interference measurement device:
FIG. 1 shows a schematic configuration of an electromagnetic interference wave measuring apparatus 10 according to the present invention. In the figure, the electromagnetic interference wave measuring apparatus 10 is provided with a turntable 30 and a noise source specifying device 41 arranged at a predetermined distance from the antenna device 20 and the antenna 24. In order to prevent radiation noise from others, the electromagnetic interference wave measuring apparatus 10 is usually installed in an anechoic chamber that shields radiation from the outside and simultaneously surrounds the inside with a radio wave absorber 32 to make it non-reflective. The antenna device 20 and the turntable 30 are connected to a control unit 44 outside the anechoic chamber by a connection cable. The control unit is connected to the central controller 48.

The antenna device 20 has an elevator 21 that also serves as a leg portion for stable installation on the floor surface, and a column 22 is erected substantially vertically from the elevator. An antenna holding portion 23 is held on the support column 22, and the antenna 24 can be attached and detached by projecting in the direction of the turntable 30 substantially horizontally with respect to the floor surface. The control unit 44 that controls the height and rotation angle of the antenna 24 in the antenna device 20 allows the antenna 24 to move vertically several meters along the support column 22 and to rotate in the vertical direction when the movement is stopped. .
Further, the antenna 24 generally needs to be appropriately changed depending on the measurement frequency band such as a biconical antenna (not shown) for measurement of radiation noise from 30 MHz to 300 MHz and a log periodic antenna 24 from 300 MHz to 1000 MHz.

The turntable 30 is disposed on the floor surface at a distance set according to the EMI measurement standard from the antenna device 20, and can be rotated 360 degrees under the control of the control unit 44. A base 31 having a predetermined height from the floor surface is placed on the turntable 30, and a device under test 50 to be measured is placed on the top surface of the base 31.
With this configuration, the height and angle of the antenna 24 can be changed with respect to the machine under test 50, and the measurement angle of the machine under test 50 with respect to the antenna 24 can also be changed by the rotation of the turntable 30. Yes, it is possible to perform measurement while holding the measuring device in an appropriate situation.

  In the present invention, as the noise source specifying device 41, a band-pass filter 41a that is connected to the antenna 24 and extracts a desired measurement frequency component as frequency selecting means, and a synchro that is a display means for inputting a signal from the band-pass filter 41a. A scope 41b, a near-field probe 41c that is connected to the synchroscope 41b by a coaxial cable and measures the magnitude of a magnetic field in a narrow range, and a probe 41b1 of the synchroscope 41b are provided. By moving the near-field probe 41c and the probe 41b1 on the device under test 50 with respect to the measurement results in a wide range measured by a commonly used measuring apparatus described later, noise is narrowed down to a narrow range. It is possible to detect and identify the noise source.

(2) Explanation of the premise EMI measuring device:
In practicing the present invention, the level of the noise generated by the EUT 50 relative to the EMI specified value and its frequency are known, and the result of EMI measurement as shown in FIG. 3 is required. As the EMI measurement, which is a prerequisite for obtaining the above result, FIG. 2 shows a schematic configuration of an electromagnetic interference wave measuring apparatus 110 that is generally used in EMI measurement. In the figure, the electromagnetic interference wave measuring device 110 is generally provided with a turntable 130 and a measuring device 140 disposed at a predetermined distance from the antenna device 120 and the antenna 124, similar to the electromagnetic interference wave measuring device 10. . In order to prevent radiation noise from others, the electromagnetic interference measuring apparatus 110 is usually installed in an anechoic chamber that shields radiation from the outside and simultaneously surrounds the interior with a radio wave absorber 132, thereby making it non-reflective. The antenna device 20 and the turntable 130 are connected to the measuring device 140 outside the anechoic chamber by a connection cable.

Here, the measuring apparatus 140 is roughly controlled by a spectrum analyzer 145 capable of displaying a spectral distribution, a preamplifier 146 that expands a measurement dynamic range, an EMI test receiver 147, the elevator 121 of the antenna 124, and the control of the turntable 130. Unit 144 and a central controller 148 for controlling these measuring instruments.
With such a configuration, the radiated electric field strength is measured using the antenna 124 for the leaked radio waves radiated from the EUT 150 into the air. The machine under test 150 is rotated by the turntable 130, and the maximum values of the horizontal and vertical components of the radiated electric field intensity radiated outside the apparatus are obtained. Further, the height of the antenna 124 is changed in a range of 1 m to 4 m so that the measurement value becomes maximum for each test frequency.

In general, the above-described measurement is automatic measurement after a predetermined setting is made in the central controller 148. The display unit of the spectrum analyzer 145 displays the peak level of the noise level at the frequency being measured, and the displayed result is displayed as a measurement result as shown in FIG. It is displayed on the display unit and output to a plotter (not shown).
In FIG. 3, the horizontal axis indicates the measurement frequency band, the vertical axis indicates the electric field strength at each frequency, and a waveform indicating the peak value of the electric field strength at each frequency is given as a measurement result. In addition, a predetermined value of EMI standard is shown in the measurement result, and a countermeasure is taken for a frequency with a small margin from the limit of the standard value in comparison with the waveform.
As described above, if the measured value exceeds the EMI regulation value, measures against the noise are required. Therefore, the noise source is identified by the electromagnetic interference measuring apparatus 10 according to the present invention. To do.
Hereinafter, noise source specification in the probe according to the present invention will be described.

(3) Noise source identification by probe:
In the measurement of the disturbance electric field intensity by the general electromagnetic disturbance wave measuring apparatus 110, the overall radiation electric field intensity of the device under test 150 can be known. However, it is necessary to know from which location the radiation is intensively emitted in order to take measures when the regulation value of the EMI regulations is exceeded.
Although an overall measure for strengthening the shield of the casing of the device under test 150 is conceivable, here a noise source is specified in order to take measures to reduce the radiation at the location where the radiation noise is generated. The noise source identification by the probe, which is a simple method for measuring local radiation, will be described.

Based on the result shown in FIG. 3 automatically measured by the electromagnetic interference wave measuring apparatus 110, the noise source is specified in order to take measures against a frequency where the noise level is larger than the specified value or a frequency with a small margin from the limit of the specified value. Do.
In addition, according to the results (not shown), the frequency and the height of the antenna 24 and the angle of the turntable 30 for the frequency are given, that is, the position where the electric field intensity radiated outside the device under test 50 is the maximum. It has been. Based on the above results, the device under test 50 is placed on the base 31 on the turntable 30 in the electromagnetic interference wave measuring apparatus 10, and the antenna device 20 is replaced with the antenna 24 corresponding to the frequency band. Then, the central controller 48 sets the height of the antenna 24 and the rotation position of the turntable to the conditions given by manual operation via the control unit 44.

When the band-pass filter 41a connected to the antenna 24 is set to the frequency by a volume or switch for adjusting the frequency band, only the noise component that is the target frequency component set by the band-pass filter 41a is extracted. . As an example, the Schmitt trigger circuit performs absolute value processing based on the extracted noise signal to generate all positive pulse signals, and outputs a time constant between pulses by a resistor and a capacitor grounded to GND. If this is given, it becomes a fluctuation component of the signal. Further, in order to eliminate the distortion of the H level signal, the comparator compares the output with an arbitrarily set reference voltage to generate a rectangular wave. In this manner, a rectangular wave having the same timing and generation period as the noise component as shown in FIG. 4 is generated from the noise signal, and is output to the synchroscope 41b as a trigger signal for specifying the generation timing.
The synchroscope 41b has a multi-channel input terminal, and a signal from the band-pass filter 41a is input to a trigger input terminal or a channel input terminal so that the input rectangular wave is triggered. .

Here, a near-field probe 41c is connected to the other channel of the synchroscope 41b, and the near-field probe 41c can be moved in the vicinity of the device under test 50. When the near magnetic field probe 41c is moved away from a place where the radiation field intensity of the noise source is strong, the input level to the synchroscope 41b becomes extremely small, and the displayed signal waveform also becomes small.
Therefore, it is possible to estimate the noise source at the frequency by detecting a signal synchronized with the timing and the generation cycle of the trigger signal from the signal obtained at the position where the near magnetic field probe 41c has moved. . The moving means of the near-field probe 41c may be automatic, but manually in this embodiment.

  A signal obtained by scanning with the near-field probe 41c is input to the synchroscope 41b. Normally, the image of the signal input to the synchroscope 41b is displayed on the display portion. However, in order to trigger the trigger signal input to another channel, a signal synchronized with the trigger signal is input. Otherwise, no trigger is applied and no image is formed on the display portion. Therefore, the input signal that forms an image on the display portion of the synchroscope 41b is a signal synchronized with the trigger signal, that is, a noise signal.

Therefore, since the position where the input signal synchronized with the trigger signal can be detected is considered as a noise source, the scanning with the near magnetic field probe 41c is continued to narrow down the range where the image is frequently formed on the display portion. . When the range of the noise source on the device under test 50 is narrowed down, as shown in FIG. 5, the range estimated as the noise source in the range on the circuit board of the device under test 50 is scanned to further narrow the range, and Next, the noise source is scanned pinpointed by the probe 41b1 of the synchroscope 41b. Again, the position where the input signal synchronized with the trigger signal can be detected from the input signal of the probe 41b1 is narrowed down.
As a result of narrowing the scanning range in this way, the noise source can be pinpointed.

(4) Modification:
FIG. 6 shows an electromagnetic interference wave measuring apparatus 210 according to this modification.
In this figure, the above-described noise source specifying device 41 according to the present invention is incorporated as a noise source specifying unit 241 in the general electromagnetic interference measuring device 110 of FIG. In the above configuration, the operation of each device does not change.

Here, the noise source specifying unit 241 is connected to the antenna 224 and serves as a frequency selection unit for extracting a desired measurement frequency component, and a synchroscope which is a display unit for inputting a signal from the bandpass filter 241a. 241b, a near-field probe 241c that is connected to the synchroscope 241b by a coaxial cable and measures the magnitude of a magnetic field in a narrow range, a probe 241b1 of the synchroscope 241b, and an informing means 241b2 connected to the synchroscope 241b It has.
As described above, by moving the near-field probe 241c and the probe 241b1 on the device under test 250 with respect to the measurement results in a wide range with a commonly used measuring apparatus, noise is narrowed down to a narrow range. It is possible to detect and identify the noise source.
The notification means 241b2 inputs a trigger signal from the bandpass filter 241a to the synchroscope 241b, inputs the signal to the LED drive circuit to light the LED light, and turns on and off the piezoelectric buzzer to output the sound. Informs the detection of noise.

The notification means 241b2 makes it possible for the observer to know the detection of noise without observing the display unit of the synchroscope 241b, and to identify the noise source while confirming the scanning range on the device under test 250. be able to.
Since the image of the detection signal is displayed simultaneously with the notification on the display unit of the synchroscope 241b, the waveform can be always observed.
Accordingly, when the rough position of the noise source is detected at the start of scanning or the like, the waveform displayed on the display unit is quickly displayed when the scanning range is quickly narrowed using the notification means 241b2 and detailed detection is performed in a narrow range. Observe. As described above, the use of the notification unit 241b2 as appropriate and the normal observation of the display unit can be used together to efficiently identify the noise source in a short time.

FIG. 7 shows a noise source specifying device 341 having no display means.
The noise source specifying device 341 includes a frequency selection unit 341a, a near magnetic field probe 341c, a comparison unit 341d, and a notification unit 341e.
As in the above modification, various processing is performed on the signal received by the antenna 324 and the rectangular wave output from the frequency selection means 341a and various frequency components detected by moving the device under test 350 with the near magnetic field probe 341c. A signal in which is mixed is input to the comparison means 341d.
The comparison means 341d monitors both inputs using an AND circuit and outputs a predetermined signal. When an AND operation is performed on the input from the rectangular wave and the near magnetic field probe 341c, when the timing of the input signal from the rectangular wave and the near magnetic field probe 341c matches, there is an input from both, and an H output is obtained. In addition, when there is no input from either or both, L output is obtained. That is, if the noise received by the antenna 324 and the noise captured in the vicinity of the device under test 350 are the same, H is output.

As described above, by taking the AND of the two inputs, the generation of a signal having the same timing and generation period as the noise signal that is the rectangular wave with respect to the signal from the near-field probe 341c is detected. It is possible to output the detection result as a signal.
Then, the H output from the frequency selecting means 341a is input to the notifying means 341e, and the output signal is input to an LED driving circuit configured to light the LED when H is input, and the LED light is turned on, By turning on the piezoelectric buzzer with H output, the detection of noise is notified to the outside by sound.
In this way, notification is performed at the same timing and length as the generation of the desired frequency component by driving with the signal synchronized with the generation of the desired frequency component input to the notification means 341e.
Therefore, the observer can detect the generation of a desired frequency component without requiring a display means.

(5) Summary:
As described above, in the present invention, only the frequency band in which noise is generated is extracted by the frequency selecting unit configured by the band pass filter 41a connected to the antenna 24, and the extracted noise signal is extracted. Generate a square wave. The rectangular wave is input to the synchroscope 41b which is a display means, a trigger is applied to the rectangular wave, and noise is detected from the input obtained by moving the vicinity of the device under test 50 with the near magnetic field probe 41c. Then, the noise source can be specified by the position of the near magnetic field probe 41c when the noise is detected. As described above, noise can be detected more efficiently than the conventional estimation of the generation source, and the noise source identification time is shortened, so that the noise countermeasure time can be shortened.

It is a schematic block diagram of the electromagnetic interference wave measuring apparatus concerning this invention. It is a schematic block diagram of a general electromagnetic interference wave measuring apparatus. It is a figure showing a measurement result. It is the schematic of the trigger production | generation with respect to an input signal. It is the schematic of noise source specification by a near magnetic field probe. It is a schematic block diagram of the electromagnetic interference wave measuring device concerning a modification. It is a schematic block diagram of the noise source specific device concerning a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Electromagnetic interference measuring device 20 ... Antenna apparatus 21 ... Elevator 22 ... Post 23 ... Antenna holding part 24 ... Antenna (log periodic antenna)
DESCRIPTION OF SYMBOLS 30 ... Turntable 31 ... Stand 32 ... Radio wave absorber 41 ... Noise source identification device 41a ... Band pass filter 41b ... Synchroscope 41b1 ... Probe 41c ... Near magnetic field probe 44 ... Control part 48 ... Central control device 50 ... Test apparatus

Claims (6)

Consists of an antenna that captures noise radiated from the UUT in a shape corresponding to the measurement frequency band, and a measuring device for analyzing the signal input from the antenna, and is placed at a predetermined distance from the antenna position In the electromagnetic interference measurement device that measures the noise radiated from the machine and gives the noise level and peak frequency as a result,
A trigger signal is generated based on the signal component extracted by adjusting the frequency band of the noise with a variable resistor or frequency selection switch using a bandpass filter that extracts a signal component of a predetermined frequency band that can be connected to the antenna and can be changed. Frequency selection means to perform,
Display means by a synchroscope for inputting and outputting a predetermined electric signal and detecting and displaying the electric signal synchronized with the trigger signal generated by the frequency selecting means;
An electromagnetic interference wave measuring apparatus comprising: a near-field probe connected to the synchroscope and outputting the electrical signal; or a noise source specifying unit comprising the synchroscope probe. In the electromagnetic interference wave measuring device composed of an antenna that captures noise radiated from the UUT in a shape corresponding to the measurement frequency band and a measuring device for analyzing the signal input from the antenna,
A frequency selecting means for extracting a signal component of a predetermined frequency band connected to the antenna and capable of changing, and generating a trigger signal based on the signal component;
Display means for detecting and displaying the electrical signal synchronized with the trigger signal generated by the frequency selection means while inputting a predetermined electrical signal;
An electromagnetic interference wave measuring device comprising: noise source specifying means comprising a probe connected to the display means and outputting the electrical signal.   3. The electromagnetic interference wave measuring apparatus according to claim 2, wherein the probe in the noise source specifying means is a narrow directivity probe.   4. The electromagnetic interference wave measuring apparatus according to claim 1, wherein the display means includes notifying means for detecting and notifying noise captured by the noise source specifying means. In the electromagnetic interference wave measuring device composed of an antenna that captures noise radiated from the UUT in a shape corresponding to the measurement frequency band and a measuring device for analyzing the signal input from the antenna,
A frequency selecting means for extracting a signal component of a predetermined frequency band connected to the antenna and capable of changing, and generating a trigger signal based on the signal component;
A noise source specifying means comprising a probe for capturing noise radiated from the device under test in the vicinity of the device under test;
Comparing means for inputting the electrical signal from the probe and inputting the trigger signal generated by the frequency selecting means, and comparing the presence or absence of both inputs;
An electromagnetic interference wave measuring apparatus comprising: an informing means for detecting and notifying an output signal of the comparing means. In the electromagnetic interference wave measuring method composed of an antenna that captures noise radiated from the UUT in a shape corresponding to the measurement frequency band and a measuring device for analyzing the signal input from the antenna,
A frequency selection step of extracting a signal component of a predetermined frequency band that is connected to the antenna and can be changed, and generating a trigger signal based on the signal component;
A display step of inputting a predetermined electric signal and detecting and displaying the electric signal synchronized with the trigger signal generated in the frequency selection step;
And a noise source identifying step comprising a probe connected to the display step and outputting the electrical signal.

Images