JP2014240775A - Electromagnetic noise detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic noise detection device which, when a high frequency signal having a frequency component simulating a transient electromagnetic noise is applied to an evaluation object, can extract only the applied noise and can correctly visualize a propagation path of the applied noise.SOLUTION: The electromagnetic noise detection device comprises: a multi-frequency signal generation unit 1 for generating a multi-frequency modulated high frequency signal by modulating a plurality of high frequency signals simulating an electromagnetic noise with a known identification signal; an application probe 3 for applying the modulated high frequency signal generated by the multi-frequency signal generation unit 1 to an evaluation object 2; a detection probe 4 for detecting the high frequency signal generated from the evaluation object 2; and a multi-frequency signal processing unit 5 for separating and demodulating, for each frequency, the high frequency signal detected by the detection probe 4, and determining, when the identification signal is included in the signal demodulated for each high frequency signal, that the high frequency signal detected by the detection probe 4 is the modulated high frequency signal applied from the application probe 3.

Description

  The present invention relates to an electromagnetic noise detection apparatus that observes a propagation path by applying a signal simulating noise to an evaluation object from the outside.

Due to the recent trend of miniaturization and higher functionality of electric / electronic products, problems caused by electromagnetic noise are increasing.
In products that are downsized and highly functional, multiple circuit boards with different functions in the same housing are concentrated in a small space, so that electromagnetic shielding members against external electromagnetic noise cannot be placed, and between circuit boards May form unnecessary bonds.
Under such circumstances, circuit boards of recent electric / electronic products are in a situation where unnecessary electromagnetic noise easily flows.

For this reason, at the stage of designing an apparatus, a technique for grasping the propagation path of electromagnetic noise on a circuit board in the apparatus is very important.
In addition, a technique for grasping the propagation path of electromagnetic noise is also required for troubleshooting when a malfunction occurs due to the influence of electromagnetic noise that the developed product does not require.

On the other hand, paying attention to external electromagnetic noise, electromagnetic noise with the nature of being transmitted at a certain frequency is often due to broadcast waves, radio waves, etc. It is easy to get clues.
However, transient electromagnetic noise typified by lightning surge and electrostatic discharge has a pulse-like waveform on the time axis, and thus includes a wide range of frequency components.
For this reason, in order to analyze the influence of transient electromagnetic noise on an electronic device, a technique for simultaneously detecting a wide range of frequency components of the electromagnetic noise is required in a short time when the electromagnetic noise is generated.

In view of this, an apparatus or system for the purpose of grasping the propagation path of electromagnetic noise is disclosed in, for example, Patent Documents 1 to 3 below.
A noise evaluation method and a noise evaluation system according to Patent Document 1 directly apply a noise signal generated by a signal generator to a connector of an evaluation object via an amplifier, a directional coupler, and a bias tee, and measure a plurality of probes. While moving sequentially to the point, the noise generated from the evaluation object is detected and its intensity is measured.
At that time, a personal computer (hereinafter referred to as PC) controls the spectrum analyzer and the signal generator to sweep the measurement frequency in the spectrum analyzer, and synchronizes the frequency of the noise signal generated by the signal generator with the sweep frequency. .
As a result, measurement data for all of a plurality of types of measurement frequencies can be obtained at one measurement point.

Further, as shown in FIG. 7, an EMI (Electro Magnetic Interference) measuring apparatus for a semiconductor device according to Patent Document 2 operates a logic pattern generator for supplying a signal for operating the semiconductor device, and a logic pattern generator. An oscillator that generates a clock signal and a phase modulator that modulates the phase of the clock signal with a sine wave are included.
The clock signal generated by the oscillator is phase-modulated by a phase modulator and input to the semiconductor device on the solid ground substrate to operate the semiconductor device.
Thereby, in the spectrum analyzer, the electromagnetic noise emitted from the semiconductor device (indicated by the alternate long and short dash line in FIG. 7) is detected as a spectrum in which the sideband is added to the fundamental wave, so the electromagnetic noise emitted from the semiconductor device, It becomes possible to clearly distinguish electromagnetic noise (indicated by a two-dot chain line in FIG. 7) emitted from a source other than the semiconductor device (for example, an apparatus for operating the semiconductor device), and as a result, accurate EMI measurement. And the evaluation can be performed.

Further, the data synthesis system of noise data and design data according to Patent Document 3 generates means for injecting noise into an evaluation object, means for detecting noise generated from the evaluation object, and generating noise data from the detected noise. And means for storing the design data of the evaluation object, and means for synthesizing the noise data and the design data stored in the storage means.
As a result, it is possible to clearly identify the path through which high-frequency noise is injected on the evaluation target, the region where the malfunction is likely to occur, the wiring pattern, and the electronic component.
Therefore, when the design is changed to a circuit that does not cause malfunction, it is not necessary to adopt the conventional try-and-error method, and the design efficiency and the number of test steps can be reduced.

JP 2010-237099 A JP 2001-83198 A JP 2001-125801 A

  However, in the example of Patent Document 1 described above, the spectrum analyzer and the signal generator are controlled to synchronize the frequency of the noise signal generated by the signal generator and the sweep of the measurement frequency in the spectrum analyzer, and the spectrum analyzer at that time receives the signal. Therefore, when the evaluation object is energized and in an operating state, the received signal is a circuit operation generated from a component or the like mounted on the evaluation object. There is no means to distinguish whether the signal is caused by a noise signal applied to the evaluation object from the signal generator, and the propagation path of only the noise signal applied to the evaluation object cannot be extracted from the signal generator. There was a problem.

On the other hand, in the example of Patent Document 2 described above, the main factor of EMI of the semiconductor device that is the evaluation target is considered as a current flowing through the solid ground substrate and the negative power supply terminal of the logic pattern generator, and this is regarded as electromagnetic noise. It is the structure to measure.
At this time, in order to determine whether the electromagnetic noise measured at the measurement point is noise directly coming from the logic pattern generator or via the semiconductor device, it can be distinguished by phase-modulating one of the signals.

Here, FIGS. 8 and 9 show the spectrum of the electromagnetic noise measured at the measurement point in FIG.
The horizontal axis is frequency and the vertical axis is power.
For simplification of description, the noise (indicated by a two-dot chain line in FIG. 7) directly coming from the logic pattern generator is referred to as noise A, and the noise via the semiconductor device (indicated by a one-dot chain line in FIG. 7). This is referred to as noise B.
For example, when the spectrum shown in FIG. 8 is received at the measurement point, the spectrum to which the sideband is not added is determined as noise A and the spectrum to which the sideband is added is determined as noise B by the above determination method. Can be distinguished.
On the other hand, the spectrum C in which the noise A and the noise B overlap as shown in FIG. 9 is determined as the noise B by the above-described determination method.
However, since this spectrum C actually includes a component of noise A, if it is determined that the spectrum C is simply noise B, the phenomenon may not be correctly grasped.
For example, when a system that analyzes a path through which noise A and noise B propagate by setting multiple points on a solid earth substrate instead of one measurement point is determined, all of the spectrum C in FIG. As a result, the path through which the noise A is actually propagated is derived as the path of the noise B, and therefore the correct path of the noise A cannot be grasped.

  As described above, in Patent Document 2 described above, when a spectrum in which a sideband is added to the fundamental wave is received, it is not possible to distinguish between noise B alone or noise A overlapping with noise A. There is a problem that the propagation path of only the applied signal cannot be visualized correctly.

  Furthermore, in Patent Document 3 described above, since the system configuration is to obtain image data by synthesizing the design object data with the noise data of the evaluation object obtained by the noise visualization measurement, the noise level obtained by the noise visualization measurement is However, it does not have a function for discriminating between the level of the signal resulting from the original circuit operation and the level of the applied noise, and there is a problem that the propagation path of only the applied noise signal cannot be visualized.

  Further, in Patent Documents 1 to 3 described above, a wide range of frequency components of electromagnetic noise cannot be detected at the same time in a short time when transient electromagnetic noise occurs with respect to transient electromagnetic noise. There has been a problem that the propagation path with respect to electromagnetic noise cannot be evaluated correctly.

  The present invention has been made to solve the above-described problems. Even when a high-frequency signal having a frequency component simulating transient electromagnetic noise is applied to an evaluation object, the applied noise It is an object of the present invention to provide an electromagnetic noise detection device that can extract only the noise and correctly visualize the propagation path of the applied noise.

  An electromagnetic noise detection device of the present invention is generated by a signal generator that generates a multi-frequency modulated high-frequency signal by modulating a plurality of high-frequency signals simulating electromagnetic noise with a known identification signal, and the signal generator. An application unit that applies a modulated high-frequency signal to the evaluation object, a detection unit that detects a high-frequency signal generated from the evaluation object, and a high-frequency signal detected by the detection unit is separated and demodulated for each frequency, A signal processing unit that determines that the high-frequency signal detected by the detection unit is a modulated high-frequency signal applied from the application unit when the demodulated signal includes an identification signal It is.

According to the present invention, when a multi-frequency modulated high-frequency signal modulated with an identification signal is applied to an evaluation object and the signal obtained by demodulating the high-frequency signal generated from the evaluation object includes the identification signal, the applied modulated signal is applied. The process of discriminating that the signal is a high-frequency signal can be performed simultaneously on multiple frequencies.
Therefore, it becomes possible to extract only the signal applied to the evaluation object for each frequency with respect to the multi-frequency modulated high-frequency signal applied at the same time. There is an effect that can be visualized.

It is a block diagram which shows the structure of the electromagnetic noise detection apparatus by Embodiment 1 of this invention. It is a block diagram which shows the structure of a multifrequency signal generation part. It is a block diagram which shows the structure of a multifrequency signal processing part. It is a flowchart which shows operation | movement of the electromagnetic noise detection apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows the data format of the high frequency signal level which the electromagnetic noise detection apparatus received, and its display method. FIGS. 6A and 6B are explanatory diagrams showing a noise distribution diagram displayed by the electromagnetic noise detection device. FIG. 6A shows all received high-frequency signals, and FIG. 6B shows only high-frequency signals based on the applied modulated high-frequency signals. (C) shows only high frequency signals other than the applied modulated high frequency signal. It is a block diagram which shows the structure of the conventional electromagnetic noise detection apparatus. It is a characteristic view which shows the spectrum of the electromagnetic noise which the conventional electromagnetic noise detection apparatus measured. It is a characteristic view which shows the spectrum of the electromagnetic noise which the conventional electromagnetic noise detection apparatus measured.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of an electromagnetic noise detection apparatus according to Embodiment 1 of the present invention.
The electromagnetic noise detection apparatus shown in FIG. 1 includes a multi-frequency signal generator 1 that modulates a multi-frequency high-frequency signal that simulates transient electromagnetic noise with a known identification signal, and a target that is modulated by the multi-frequency signal generator 1. An application probe 3 that applies a modulated high-frequency signal to the evaluation object 2, a detection probe 4 that detects a high-frequency signal generated from the evaluation object 2, and a multi-frequency high-frequency signal detected by the detection probe 4 Each frequency component is classified and demodulated, compared with the identification signal, and whether the high-frequency signal detected by the detection probe 4 is a modulated high-frequency signal applied from the application section probe 3 is determined for each frequency. The multi-frequency signal processing unit 5 for determining the frequency, the distribution unit of the high-frequency signal level based on the determination result of the multi-frequency signal processing unit 5, and the display unit 6 for displaying and the control unit 7 for controlling each unit Prepare.

The evaluation object 2 is disposed on the stage base 21.
The evaluation object 2 is a printed wiring board that constitutes some electronic device or electronic circuit, and is provided with a connector 22 for connection to the outside.
The connector 22 is a connector for supplying power to the evaluation object 2 or a connector for performing signal transmission and communication with an external device.
The evaluation object 2 receives power supply through the connector 22 and performs signal transmission with the outside.
In the first embodiment, it is assumed that the power supply cable 23 is connected to the connector 22 and the power is supplied to the evaluation object 2, and the signal transmission and communication with the outside are assumed. If necessary, it is assumed that connection with an external device is made through the communication cable 23 and the connector 22 as appropriate.

Next, details of the multi-frequency signal generator 1 will be described.
The multi-frequency signal generator 1 shown in FIG. 2 includes a multi-frequency carrier generator 11, an identification signal generator 12, a distributor 13, a multi-frequency modulator 14, and a synthesizer 15, and simulates transient electromagnetic noise. The modulated multi-frequency modulated high frequency signal is generated and output to the applying probe 3.

  The multi-frequency carrier generation unit 11 has a function of outputting a multi-frequency high-frequency carrier that is a source of a multi-frequency modulated high-frequency signal based on a command from the control unit 7. The generating unit 11N is configured by a plurality of signal generators, for example.

The identification signal generation unit 12 has a function of outputting a signal based on an instruction from the control unit 7, and is configured by, for example, a signal generator, a function generator, or a pulse generator.
The identification signal output from the identification signal generator 12 may be a continuously changing analog signal or a discretely changing digital signal.

The multi-frequency modulation unit 14 outputs the multi-frequency high-frequency carrier wave output from the multi-frequency carrier wave generation unit 11 by the identification signal output from the identification signal generation unit 12 and distributed for each frequency through the distributor 13. For example, it has a function of performing modulation, and includes, for example, a plurality of analog modulation circuits or a plurality of digital modulation circuits including the first modulation unit 141 to the Nth modulation unit 14N.
The plurality of modulation units select a modulation method based on a command from the control unit 7 and modulate a plurality of high-frequency signals.
Therefore, the signal output from the multi-frequency modulation unit 14 becomes a plurality of modulated high-frequency signals.
The plurality of modulated high-frequency signals are combined into one multi-frequency modulated high-frequency signal by the synthesizer 15 and input to the applying probe 3.

Next, details of the application unit will be described.
The application unit includes an application probe unit 3.
The application probe 3 is attached to the power supply cable 23 or the communication cable 23 connected to the evaluation object 2.
The application probe 3 has a connection terminal connected to the multi-frequency signal generator 1 and applies a multi-frequency modulated high-frequency signal input from the multi-frequency signal generator 1 to the attached cable 23. .
With the configuration described above, a multi-frequency modulated high-frequency signal simulating transient electromagnetic noise can be input to the evaluation object 2 in operation.

Next, details of the detection unit will be described.
The detection unit may include at least the detection probe 4 and may include a stage base 21, a support unit 24, a drive unit 25, and a gantry 26 in addition to the detection probe 4.
The detection probe 4 has a function of detecting a high-frequency signal generated from the evaluation object 2 in a state where the multi-frequency modulated high-frequency signal is applied from the application probe 3. For example, a magnetic field using a micro loop antenna is used. It is composed of a probe or an electric field probe using a microstrip antenna.
The detection probe 4 is supported by a support portion 24 and can be moved together with the support portion 24 by a drive portion 25 that drives the support portion 24.

The drive unit 25 is configured with respect to four axes of the stage table 21 in the horizontal direction (X direction), the vertical direction (Y direction), the height direction (Z direction), and the angle of the detection probe 4 (θ direction). The detection probe 4 has a function of moving, and is constituted by, for example, a stepping motor and a motor controller.
The drive unit 25 is movably attached to a gantry 26 installed on the stage base 21 and can move the position and orientation of the detection probe 4 in accordance with a command from the control unit 7. .
Therefore, the detection probe 4 can be guided to an arbitrary position of the evaluation object 2 installed on the stage base 21.

In the above description, the drive unit 25 is configured to move the detection probe 4 in the X, Y, and Z directions with respect to the evaluation object 2. The object 2 may be configured to move in the X, Y, and Z directions.
That is, it suffices if the detection probe 4 and the evaluation object 2 are relatively changed in positional relationship so that a high-frequency signal at an arbitrary position in the evaluation object 2 can be detected.

  With the configuration described above, it is possible to detect a high-frequency signal generated from the operating evaluation object 2 to which a multi-frequency modulated high-frequency signal simulating transient noise is input, at an arbitrary position of the evaluation object 2. it can.

Next, details of the multi-frequency signal processing unit 5 will be described.
The multi-frequency signal processing unit 5 shown in FIG. 3 includes a distributor 51, a frequency classification receiving unit 52, a multi-frequency demodulating unit 53, and a multi-frequency discriminating unit 54, and receives a high-frequency signal detected by the detection probe 4. Then, it is determined whether or not it is based on the multi-frequency modulated high-frequency signal generated by the multi-frequency signal generator 1.

  The frequency classification receiving unit 52 extracts a high-frequency signal having an arbitrary frequency from the multi-frequency high-frequency signal output from the detection probe 4 and distributed by the distributor 51 based on an instruction from the control unit 7, and the high-frequency signal For example, the first filter 5211 to the Nth filter 521N and the first receiving unit 5221 to the Nth receiving unit 522N are configured.

  At this time, when the cut-off frequency of the filter can be changed appropriately, or when the super regenerative detection method is used in the detection circuit of the reception unit, the frequency classification reception unit 52 uses a command from the control unit 7 to Corresponding to the multi-frequency modulated high-frequency signal output from the multi-frequency signal generator 1, the setting of the frequency of the high-frequency signal extracted by the filter and the setting of the frequency of the high-frequency signal received by the plurality of receivers are made.

The multi-frequency demodulator 53 has a function of performing demodulation processing based on a command from the controller 7 on multi-frequency high-frequency signals received by a plurality of receivers. The demodulator 53N includes an analog demodulator circuit or a digital demodulator circuit.
The multi-frequency demodulator 53 performs demodulation processing on the high-frequency signal received by the frequency classification receiver 52 to generate a demodulated signal, and outputs the demodulated signal to the multi-frequency discriminator 54.

The multi-frequency discriminating unit 54 receives the information of the identification signal, which is a signal set by the identification signal generating unit 12, from the control unit 7, and the demodulated signal output from each demodulating unit of the multi-frequency demodulating unit 53 and the identification signal And a function of determining whether the demodulated signal and the identification signal match. For example, it is composed of a comparator and a bit arithmetic unit including the first determination unit 541 to the Nth determination unit 54N. is there.
The determination method is determined based on an instruction from the control unit 7, and the determination result is output to the control unit 7.

When the known identification signal can be extracted from the demodulated signal obtained by demodulating the high-frequency signal, the multi-frequency determining unit 54 determines that the high-frequency signal is the modulated high-frequency signal applied from the application probe 3, and It is determined that a signal other than the modulated high-frequency signal is mixed in the high-frequency signal, and is determined not to be a modulated high-frequency signal.
This discrimination process is performed on a plurality of high-frequency signals input from a plurality of receivers, and a plurality of modulated high-frequency signals included in the multi-frequency modulated high-frequency signal are identified.

  With the configuration described above, a multi-frequency modulated high-frequency signal simulating transient noise is input, and a high-frequency signal generated from the operating evaluation object 2 is output from the multi-frequency signal generator 1. It is possible to determine whether the signal is a multi-frequency modulated high-frequency signal.

Next, details of the display unit 6 will be described.
The display unit 6 draws and displays a noise distribution on the evaluation object 2.
The display unit 6 has a function of acquiring and displaying high-frequency signal level data received by the frequency classification receiving unit 52, and includes, for example, a PC and a monitor.
In the case of this configuration, the PC executes the program in which the processing content of the display unit 6 is described, and displays the execution result on the monitor, thereby taking on the function of the display unit 6.

The display unit 6 not only displays the level of the high-frequency signal detected at an arbitrary position of the evaluation object 2, but also each coordinate position obtained by dividing the XY plane (scan area) of the arbitrary range of the evaluation object 2 into a lattice shape It is possible to display the level of the high-frequency signal detected by.
By illustrating the arrangement of the high-frequency signal level data in the scan area with contour lines (so-called contour diagram), the high-frequency signal level distribution of the evaluation object 2 on the XY plane, that is, the noise distribution can be displayed.
Next, details of the control unit will be described.

The control unit 7 controls the entire electromagnetic noise detection device.
The control unit 7 has a function of controlling the operations of the multi-frequency signal generation unit 1, the multi-frequency signal processing unit 5, the drive unit of the detection probe 4, and the display unit 6, and is configured by a PC, for example. It is.
In the case of this configuration, the PC assumes the function of the control unit by executing a program in which the processing content of the control unit 7 is described.

The control unit 7 has a function of receiving an operation setting input from a user who uses the electromagnetic noise detection device.
As the operation setting information, the user sets a plurality of values or ranges of the frequency of the carrier wave that plots the noise distribution, a plurality of carrier wave levels, the type and level of the identification signal, and the modulation / demodulation method of the multi-frequency modulation unit 14 and the multi-frequency demodulation unit 53 The position or scan area where the detection probe 4 detects a high-frequency signal, the operating condition of the frequency classification receiving unit 52, the determination method of the multi-frequency determination unit 54, and the display method information of the display unit 6 are set.
The control unit 7 issues a command to each unit under control based on the operation setting information.

Here, the operation of the electromagnetic noise detection apparatus according to the control of the control unit 7 will be described with reference to the flowchart shown in FIG.
In step ST1, based on the frequency range for plotting the noise distribution in the operation setting information set by the user, the control unit 7 sets the frequency range to the number of carrier generation units (N in this embodiment). The value of each frequency corresponding to the discrete frequency sequence divided in step 1 is transmitted from the first carrier generation unit 111 to the Nth carrier generation unit 11N.
In addition, the level value of each carrier wave is transmitted from the first carrier wave generator 111 to the Nth carrier wave generator 11N.
Upon receiving these commands, the first carrier generation unit 111 to the Nth carrier generation unit 11N generate a carrier having a frequency and a level according to the command.

In step ST <b> 2, the control unit 7 transmits the type and level of the identification signal in the operation setting information to the identification signal generation unit 12.
Upon receiving this command, the identification signal generator 12 generates a type of identification signal corresponding to the command, for example, a sine wave or pulse wave bit pattern waveform at a level corresponding to the command.

In step ST3, the control unit 7 transmits the modulation method in the operation setting information from the first modulation unit 141 to the Nth modulation unit 14N.
Upon receipt of this command, the first modulation unit 141 to the N-th modulation unit 14N perform switching of a modulation circuit or software of a modulation method (for example, amplitude modulation and quaternary phase shift keying (QPSK)) according to the command. Then, each carrier wave output from the first carrier wave generation unit 111 to the Nth carrier wave generation unit 11N is modulated by the identification signal output from the identification signal generation unit 12 via the distributor 13.
Each modulated high-frequency signal is synthesized by the synthesizer 15 to generate one multi-frequency modulated high-frequency signal.
With the above operation, preparation for inputting a multi-frequency modulated high-frequency signal based on a command from the control unit 7 is completed.

In step ST <b> 4, the control unit 7 transmits the operating condition of the frequency classification receiving unit 52 in the operation setting information to the frequency classification receiving unit 52.
For example, when the frequency classification receiving unit 52 includes a digital filter, a cut-off frequency or the like is configured so that the bandpass filter is configured with the frequency output from the first carrier generation unit 111 to the Nth carrier generation unit 11N as the center frequency. Send information.
Receiving these instructions, the first filter 5211 to the Nth filter 521N change the setting according to the instructions.

In step ST5, the control unit 7 transmits the demodulation method in the operation setting information from the first demodulation unit 531 to the Nth demodulation unit 53N.
The first demodulator 531 to the N-th demodulator 53N receiving this command, the demodulation method (for example, amplitude modulation and quaternary phase) corresponding to the command from the first modulator 141 to the N-th modulator 14N in step ST3. Switching of the demodulation circuit of shift modulation etc. or software is performed according to the command.
As a result, preparation for performing demodulation processing on each high-frequency signal output from the first demodulator 531 to the N-th demodulator 53N is completed.
In the demodulation process, when each high frequency signal is based on the modulated high frequency signal, the identification signal can be extracted from the demodulated signal obtained by demodulating each high frequency signal.
On the other hand, when each high-frequency signal is not based on the modulated high-frequency signal or when there is interference, the identification signal cannot be extracted from the demodulated signal.

In step ST6, the control unit 7 transmits the type and level of the identification signal in the operation setting information and the determination method of the multi-frequency determination unit 54 from the first determination unit 541 to the Nth determination unit 54N.
Upon receiving these instructions, the first to Nth discriminating units 541 to 54N determine the discriminating method corresponding to the type and level of the identification signal, for example, a waveform amplitude comparator and a bit pattern comparator, according to the command. Switch the circuit or software.
Further, the first determination unit 541 to the Nth determination unit 54N acquire information included in the command from the control unit 7, for example, an amplitude threshold value used for determination, a bit pattern correlation rate, or the like.
Thereby, it is determined whether the identification signal is included in the demodulated signal output from the first demodulator 531 to the Nth demodulator 53N, that is, whether each high frequency signal is based on the modulated high frequency signal. I'm ready.
In the discrimination process, each demodulated signal and each identification signal are compared, and the result of the comparison is applied to the amplitude threshold value or the correlation rate of the bit pattern. (Or whether each identification signal is included in each demodulated signal).
Each determination result is fed back to the control unit 7.

In step ST <b> 7, the control unit 7 transmits the display method of the display unit 6 in the operation setting information to the display unit 6.
Upon receiving this command, the display unit 6 switches the display method according to the command.
For example, when the display unit 6 is configured by a PC, a display program is started.
Also, drawing settings necessary for noise distribution drawing (for example, setting of noise distribution scale and display color) are performed.

  When the setting of each part of the electromagnetic noise detection device is completed and ready, in step ST8, the control unit 7 issues a command to the multi-frequency signal generating unit 1 to generate a multi-frequency modulated high-frequency signal.

  In step ST <b> 9, the multi-frequency modulated high-frequency signal generated by the multi-frequency signal generator 1 is input to the application probe 3 and applied to the evaluation object 2 via the cable and the connector 22.

In step ST10, the control unit 7 drives the information on the position coordinates where the detection probe 4 detects the high-frequency signal in the operation setting information, or the information on the extreme end coordinates in the scan area where the high-frequency signal is detected. To the unit 25.
Upon receiving this command, the drive unit 25 moves and holds the support unit 24 and the detection probe 4 to the coordinates according to the command.

  In step ST11, the detection probe 4 held at a predetermined coordinate position on the evaluation object 2 detects a high-frequency signal generated from the evaluation object 2, and in step ST12, the detected high-frequency signal is received by frequency classification. The multi-frequency demodulation unit 53 demodulates the received high-frequency signal in step ST13.

In step ST14, as a result of the comparison between the identification signal and the demodulated signal by the multi-frequency discriminating unit 54, it is determined that the identification signal and the demodulated signal are the same or the demodulated signal includes the identification signal (step ST14 " YES ”), the level of the high-frequency signal received by the frequency classification receiver 52 is based on the modulated high-frequency signal applied from the application probe 3, propagated through the evaluation object 2, and detected by the detection probe 4. Judge.
The control unit 7 receiving the feedback of the determination result instructs the display unit 6 to display the level of the high-frequency signal received by the frequency classification receiving unit 52.
A specific example of the display in step ST15 will be described later.

  On the other hand, as a result of the comparison between the identification signal and the demodulated signal, if the identification signal does not match the demodulated signal or the demodulated signal does not contain the identification signal (step ST14 “NO”), without displaying (step ST16), The display unit 7 is instructed to store the level of the high frequency signal received by the frequency classification receiving unit 52 as data different from the case where the identification signal and the demodulated signal match.

  When the scan area is set as the operation setting information, in step ST17, the control unit 7 confirms whether or not the high-frequency signal has been detected in all the coordinates in the scan area, and has not ended. (Step ST17 “NO”), returning to Step ST10, the control unit 7 sequentially transmits information on each of the grid-like coordinates in the scan area to the drive unit 25, and the drive unit 25 is the end of the scan area. From the coordinate, it moves to the next coordinate according to the command of the control unit 7.

  When the above operations (steps ST11 to ST17) are repeated for each coordinate and the detection of the high-frequency signal is completed at all the coordinates in the scan area (step ST17 “YES”), the evaluation object 2 is obtained at a plurality of carrier frequencies. It is possible to plot a noise distribution in the scan area of only a plurality of modulated high-frequency signals applied to (step ST18).

When the above operations (steps ST1 to ST18) are finished, it is possible to draw a noise distribution in the scan area of only the modulated high-frequency signal applied to the evaluation object 2 at a plurality of carrier frequencies.
A specific example of the display in step ST18 will be described later.

Next, a specific example of display by the display unit 6 will be described.
FIG. 5 is a diagram for explaining a data format of a high-frequency signal level received by the frequency classification receiving unit 52 and a display method thereof.
In FIG. 5, the grid of the scan area represents the detection position of the high-frequency signal when the entire XY plane of the evaluation object 2 or a part thereof is the scan area, and the numbers in the grid are the coordinates (X, Y).
Since the high-frequency signal generated from the evaluation object 2 is received by the N-th receiving unit 522N from the plurality of first receiving units 5221, for example, the high-frequency signal detected by the detection probe 4 at the coordinates (1, 1). The integration of the data of each high-frequency signal level received by the Nth receiver 522N from the first receiver 5221 has a series of values for the frequency f.

The high frequency signal level data acquired from the scan areas at coordinates (1, 1) to (5, 5) is two-dimensional array data.
For example, a two-dimensional array of high-frequency signal levels in a scan area of one frequency becomes a noise distribution diagram expressed by a contour diagram or the like.
In the noise distribution diagram, the magnitude of the high-frequency signal level is expressed by changing the drawing color, shading, and the like.

  Further, the data of the two-dimensional array of each frequency overlaps in the direction of the frequency f and becomes the data of the three-dimensional array.

In the case of step ST15, the multi-frequency high-frequency signal level without sweeping by the scan area is displayed.
Therefore, the display unit 6 plots and displays the high-frequency signal level at any one coordinate position, for example, like the high-frequency signal level in FIG.
As a display method in this case, a one-dimensional plotting method such as fixing the coordinate position at a certain point and graphing the high-frequency signal level with respect to the frequency can be considered, and the display unit 6 is operated by the control unit 7. Set the maximum scale value, line type, thickness, etc. according to the setting information.

In the case of step ST18, the multi-frequency high-frequency signal level swept in the scan area is displayed.
Therefore, the display unit 6 draws two-dimensional array data on a plane for each frequency and displays it as three-dimensional array data superimposed in the frequency direction.
However, if the display method is a two-dimensional contour diagram, the noise distribution of each frequency cannot be displayed at the same time, so display the contour diagram of all frequencies side by side or enter the frequency in a dialog box etc. Thus, it is configured to display a contour diagram of an arbitrary frequency.

FIG. 6 shows an example of a noise distribution diagram displayed on the display unit 6.
Here, the magnitude of the high-frequency signal level is expressed by shading, and the higher the high-frequency signal level, the higher the level.
FIG. 6A shows a noise distribution diagram when the high frequency signal received by the frequency classification receiving unit 52 is not discriminated by the multi-frequency discriminating unit 54.
In this noise distribution diagram, when a modulated high-frequency signal is applied from the lower right of the scan area at a certain frequency, it is generated from some other noise having the same frequency from the lower left (for example, a component mounted on the evaluation object 2 or the like). It shows a situation in which a signal caused by circuit operation, or an external device for operating the evaluation object 2 and noise generated from the surrounding radio wave environment are invading.
In this case, since the frequencies of the modulated high-frequency signal and another noise match, the spectrum analyzer or the like of the frequency separation receiving unit 52 cannot separate them.
Accordingly, when the display unit 6 plots the noise distribution as it is based on the received high-frequency signal, a noise distribution in which the high-frequency signal based on the modulated high-frequency signal and another noise are mixed as illustrated in FIG. It will be.
Thus, it is not possible to extract only the propagation path of the modulated high-frequency signal.

On the other hand, FIG. 6B shows a noise distribution diagram of the high-frequency signal based on the modulated high-frequency signal when the multi-frequency discriminating unit 54 discriminates the high-frequency signal received by the frequency classification receiving unit 52.
By performing the discrimination processing, it is possible to display only the high-frequency signal level at a location where the identification signal included in the modulated high-frequency signal can be demodulated among the high-frequency signals received in the scan area.
As is clear from a comparison between FIG. 6A and FIG. 6B, another noise distribution that enters from the lower left of the scan area displayed in FIG. 6A is displayed in FIG. 6B. Not.

Furthermore, since the display unit 6 stores the high-frequency signal level at a location where the identification signal included in the modulated high-frequency signal can be demodulated and the high-frequency signal level at a location where it cannot be demodulated, the high-frequency signal level at a location where demodulation cannot be performed. You can also display only.
FIG. 6C shows a noise distribution diagram of a high-frequency signal that is not based on the modulated high-frequency signal when the high-frequency signal received by the frequency separation receiving unit 52 is discriminated by the multi-frequency discriminating unit 54.
That is, this coincides with some other noise distribution having the same frequency as that of the high-frequency signal propagating from the lower left of the scan area shown in FIG.

  Accordingly, it is possible to extract only the propagation path of the multi-frequency modulated high-frequency signal applied to the evaluation object 2 from the application probe 3, and to extract only some other noise distribution of the same frequency. As a result, it is possible to separate these two signals.

  Further, since the distribution of the multi-frequency modulated high-frequency signal can be extracted simultaneously, a multi-frequency noise distribution corresponding to the distribution of transient electromagnetic noise having a wide band can be obtained.

  Therefore, the control unit 7 controls each unit synchronously, and both the investigation analysis of the distribution of unnecessary noise in the evaluation object 2 and the acquisition of the applied noise (modulated high frequency signal) are performed in a wide frequency range. Can be realized.

As described above, according to the first embodiment, the electromagnetic noise detection device generates a multi-frequency modulated high-frequency signal by modulating a multi-frequency high-frequency signal simulating transient electromagnetic noise with a known identification signal. A multi-frequency signal generating unit 1 for applying the multi-frequency modulated high-frequency signal generated by the multi-frequency signal generating unit 1 to the evaluation object 2, and a high-frequency signal generated from the evaluation object 2 Detection probe 4 and the high-frequency signal detected by detection probe 4 are classified and demodulated for each frequency component, and the identification signal is included in the demodulated signal. And a multi-frequency signal processing unit 5 that simultaneously determines for each frequency that the high-frequency signal is a modulated high-frequency signal applied from the application probe 3.
For this reason, unnecessary noise can be separated from the noise generated in the evaluation object 2 and only the multi-frequency noise applied to the evaluation object 2 can be extracted.
Therefore, it is possible to correctly visualize the propagation path of the applied multi-frequency noise based on the extraction result.
Further, since the distribution of the multi-frequency modulated high-frequency signal can be extracted simultaneously, a multi-frequency noise distribution corresponding to the distribution of transient electromagnetic noise having a wide band can be obtained.

Furthermore, according to the first embodiment, the electromagnetic noise detection device is determined to be a multi-frequency modulated high-frequency signal applied from the application probe 3 among the high-frequency signals detected by the detection probe 4. The display unit 6 for displaying the distribution of the received signals is provided.
For this reason, the propagation path of the multi-frequency noise applied to the evaluation object 2 can be correctly visualized.

Furthermore, according to the first embodiment, the display unit 6 is a signal that is not a modulated high-frequency signal applied from the application probe 3 among the high-frequency signals detected by the detection probe 4, that is, the evaluation object 2. Signals caused by circuit operations generated from components mounted on the device, or unnecessary signals generated from sources other than the evaluation object 2 (for example, a device for operating the evaluation object 2 or the surrounding radio wave environment) You may comprise so that the distribution of noise may be displayed.
In the case of this configuration, it is possible to visualize the distribution of unnecessary noise in the evaluation object 2, which helps the investigation and analysis of the unnecessary noise distribution in the evaluation object 2.

  In the present invention, within the scope of the invention, any component in the embodiment can be modified or any component can be omitted in the embodiment.

  DESCRIPTION OF SYMBOLS 1 Multi-frequency signal generation part, 2 Evaluation object, 3 Application part probe, 4 Detection probe, 5 Multi-frequency signal processing part, 6 Display part, 7 Control part, 11 Multi-frequency carrier wave generation part, 12 Identification signal generation part, 13, 51 Divider, 14 Multi-frequency modulator, 15 Synthesizer, 21 Stage base, 22 Connector, 23 Cable, 24 Support section, 25 Drive section, 26 Mounting base, 52 Frequency separation receiver, 53 Multi-frequency demodulator, 54 Multi-frequency discriminator, 111-11N First carrier generator to Nth carrier generator, 141-14N First modulator to Nth modulator, 531 to 53N First demodulator to Nth demodulator, 541 to 54N 1st discriminator to Nth discriminator, 5221 to 521N 1st filter to Nth filter, 5221 to 522N 1st receiver to Nth receiver.

Claims (4)

A signal generation unit that generates a multi-frequency modulated high-frequency signal by modulating a plurality of high-frequency signals simulating electromagnetic noise with a known identification signal;
An applying unit that applies the modulated high-frequency signal generated by the signal generating unit to an evaluation object;
A detection unit for detecting a high-frequency signal generated from the evaluation object;
The high-frequency signal detected by the detection unit when the high-frequency signal detected by the detection unit is classified and demodulated for each frequency and the identification signal is included in the demodulated signal for each high-frequency signal. An electromagnetic noise detection apparatus comprising: a signal processing unit that determines that a signal is the modulated high-frequency signal applied from the application unit.   2. The electromagnetic wave according to claim 1, further comprising: a display unit that displays a distribution of signals determined to be modulated high-frequency signals applied from the application unit among the high-frequency signals detected by the detection unit. Noise detection device.   2. The electromagnetic noise according to claim 1, further comprising: a display unit that displays a distribution of signals determined not to be modulated high-frequency signals applied from the application unit among the high-frequency signals detected by the detection unit. Detection device. The signal generator is
2. The electromagnetic noise detection apparatus according to claim 1, wherein a plurality of high-frequency signals simulating transient electromagnetic noise are modulated with a known identification signal to generate a multi-frequency modulated high-frequency signal.

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