JPH07104381B2 - EMI measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an EMI (electoromagnetic interferenc) used in a spectrum analyzer for measuring interference noise affecting various electronic devices and the like and other similar devices.
e: Radio noise interference) measuring apparatus, and in particular, relates to an EMI measuring apparatus capable of appropriately displaying and measuring desired measurement result data and having a function of editing the measurement result data.

[Conventional technology]

In the conventional EMI measurement of this type, in order to investigate what frequency of noise is distributed by using a spectrum analyzer or the like, as shown in FIG. After measuring the noise spectrum distribution shown in, the noise spectrum is compared with the standard level (b) determined from the desired signal component, interference noise level, etc., and the noise spectrum exceeding this standard level (b) The so-called preliminary measurement is performed by sequentially registering the local maximum points (peak points) of ,, and frequencies fa, fb, and fc in the memory (step A1).

After that, the frequency that becomes the evaluation target point registered in the memory
Select any one point from fa, fb, fc (Step A
2) Measure the noise spectrum distribution near the selected frequency, magnify and repeatedly display it, and if necessary, change the environmental condition of the DUT to set the noise level to the maximum (step A3). Further, the noise level of the selected frequency is detected again while changing various time constants based on the QP detection method defined by CISPR (Special Committee on International Radio Interference), and is shown in FIG. 8 (b). A final evaluation measurement is performed to determine whether the detected outputs', ',' exceed the standard level (a) (step A
Four).

When the final evaluation of the noise level of one frequency is completed as described above, the process returns to step S2 to select another frequency registered in the memory again, and evaluate and measure the noise level of that frequency. Do (step
A2-A4). Note that conventionally, the operation of enlarged display shown in step S3 may be omitted.

[Problems to be Solved by the Invention]

However, in the above EMI measurement, since the noise level of only the registered frequency is evaluated and measured, the noise level of the frequency that is not registered cannot be evaluated and the appropriate evaluation cannot be expected. Even if the frequency to be measured is known, if the noise level fluctuates with time, the desired frequency cannot be registered in the preliminary measurement stage. Further, since all the noise spectrums exceeding the standard level (a) among the noise spectrum distributions obtained by the preliminary measurement are subject to the evaluation measurement, they are not originally subject to the evaluation measurement such as external waves and broadcast waves. Since the evaluation and measurement are also performed for the frequencies considered to be, there is a problem that it takes a lot of time to complete the final evaluation.

The present invention has been made in view of the above circumstances, and provides an EMI measuring device that can appropriately select data of a desired measurement result and quickly evaluate the data, and can significantly reduce the time of final evaluation. With the goal.

Another object of the present invention is to provide an EMI measuring device that can easily exclude unnecessary noise spectrum such as external waves from the evaluation measurement target, and can easily evaluate unnecessary frequencies as evaluation target points. To provide.

Further, another object of the present invention is to provide an EMI measuring device that effectively utilizes the already obtained evaluation target points to shorten the evaluation time.

[Means for Solving the Problems]

In order to solve the above problems, the EMI measuring device according to the present invention measures a noise spectrum distribution in a wide frequency range,
In the EMI measuring device for evaluating the noise spectrum, the measured noise spectrum is compared with a predetermined standard level, and when the noise spectrum is equal to or higher than the standard level, the frequencies of the noise spectrum are sequentially registered in the first memory. In addition, the noise spectrum distribution waveform data obtained by logarithmically converting the noise spectrum distribution in the wide frequency range is stored in the second memory and is displayed on the display device, and the preliminary measurement control means is used to store the noise measurement data. Evaluation measurement control means for performing evaluation measurement by sequentially setting each frequency registered in the first memory as an evaluation target point, storing the obtained evaluation measurement waveform data in the third memory and displaying the same on the display device, Preliminary measurement waveform data stored in the second memory according to the content selection key, stored in the third memory Display content selection control means for selectively displaying any of the evaluated measurement waveform data and the expanded waveform data obtained by measuring the noise spectrum in the vicinity of the frequency to be evaluated registered in the first memory. Preliminary measurement waveform displayed by the preliminary measurement control means,
When the evaluation measurement waveform displayed by the evaluation measurement control unit, the preliminary measurement waveform selected and displayed by the display content selection control unit, or the evaluation measurement waveform is displayed, a marker is attached to a desired evaluation target point and the marker is attached. And a marker movement control means for moving the marker.

Further, in addition to the above-mentioned means, the device of the present invention is an evaluation target point adding means for setting a frequency and adding an evaluation target point, and an evaluation target point for setting a frequency for an already registered evaluation target point and deleting it. And a deleting means.

Further, in the device of the present invention, the non-volatile storage device is stored in either of the above means, and the evaluation target point in the first memory is stored in the non-volatile storage device. This is a structure in which a store / recall control means for reproducing is added to the memory of No. 1.

[Action]

Therefore, according to the present invention, by taking the above-mentioned means, the preliminary measurement control means sequentially registers the frequencies to be evaluated from the noise spectrum and the standard level in the first memory, and the noise spectrum distribution is logarithmically converted. To obtain a preliminary measurement waveform, store it in the second memory, and
Display on the display device. Next, in the evaluation measurement control means,
The evaluation target point registered in the memory is evaluated by QP measurement, and the evaluation measurement waveform data is stored in the third memory and displayed on the display device. Further, the display content selection control means appropriately designates the evaluation measurement waveform data or the evaluation measurement waveform data after completion of the preliminary measurement or the evaluation measurement, and further specifies the frequency to be the evaluation target point that has already been registered and determines the frequency in the vicinity of the frequency. By selecting one of the expanded waveforms obtained by measuring and expanding the noise spectrum distribution, it is possible to observe the desired waveform and quickly perform appropriate evaluation. Moreover, the marker movement control means attaches the marker to the required evaluation target point while moving it, so that the evaluation can be performed while comparing the levels of the mutual evaluation target points.

In addition, by providing means for adding and deleting points to be evaluated, even those missing from registration can be easily added and evaluated as points to be evaluated, or unnecessary evaluation points can be deleted to reduce the time required for evaluation. Can be shortened.

Further, according to the present invention, the evaluation / recall control means can store the evaluation target point in the non-volatile storage device, and the evaluation target point can be recalled when necessary to perform the evaluation measurement, and the preliminary measurement and the like can be omitted. be able to.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the function of the device of the present invention. Preliminary measurement key 1, marker movement key 2, evaluation measurement key 3, selection key 4 for selecting display contents, additional key for additionally instructing evaluation target points. 5, a delete key 6 for deleting the already-registered evaluation target points is provided, and key signals from these keys 1 to 6 are sent to the system control means 7. The system control means 7 has a function of receiving a key signal from any one of the keys 1 to 6 and outputting a signal for executing a predetermined control and program.

Reference numeral 8 is a preliminary measurement control means for executing a preliminary measurement program by a signal issued from the system control means 7 based on the key signal of the preliminary measurement key 1, which is a spectrum measurement for measuring a noise spectrum distribution in a wide frequency range. Means 9, a memory 10 in which the noise spectrum distribution is sequentially stored and predetermined standard data is stored, the noise spectrum is compared with the standard data, and the frequency of the noise spectrum exceeding the standard data is determined. It has a registration memory 11 registered as an evaluation target point, a preliminary measurement memory 12 for storing noise spectrum distribution waveform data which is a preliminary measurement waveform obtained by logarithmically converting the noise spectrum distribution, and particularly the evaluation target point. Frequency registration and logarithmic conversion of the noise spectrum distribution waveform data are acquired. It has the function of displaying the noise spectrum distribution waveform data to the display device 13 on. Note that a marker is displayed as an initial evaluation target point at the maximum level point in the noise spectrum distribution displayed on the display device 13.

Reference numeral 14 is an evaluation measurement control means for executing an evaluation measurement program with a signal issued from the system control means 7 based on the key signal of the evaluation measurement key 3, and here, the evaluation target points registered in the registration memory 11 are stored. Each frequency is selected one by one, and evaluation measurement, that is, quasi-peak value or average value detection is performed to obtain evaluation measurement waveform data, which is stored in the evaluation measurement memory 15 and displayed on the display device 13. Have the ability to At this time, a marker is displayed at the current evaluation target point displayed on the display device 13.

Reference numeral 16 denotes display content selection control means for executing a display content selection program in response to a signal issued from the system control means 7 based on the key signal of the selection key 4, and here, noise stored in the preliminary measurement memory 12 The spectrum distribution waveform data is displayed on the display device 13, the evaluation waveform data stored in the evaluation measurement memory 15 is displayed on the display device 13, or the noise spectrum distribution in the vicinity of the frequency of the evaluation target point is displayed via the spectrum measuring means 9. Real-time monitor for measurement and enlarged display has a function to select and display any of the displays by measurement.

Reference numeral 17 denotes a display device 13 in any of the preliminary measurement control means 8, the evaluation measurement control means 14 and the display content selection control means 16.
The marker movement control means moves the mark attached to the evaluation target point of the noise spectrum distribution waveform and the evaluation measurement waveform displayed in FIG.

Further, this apparatus is provided with an evaluation target point addition means 21 and an evaluation target point deletion means 22. The evaluation target point adding means 21 specifies a certain frequency to identify the registered memory 11
The evaluation target point deleting means 22 has a function of deleting unnecessary ones such as extraneous waves from the evaluation target points of each frequency registered in the registration memory 11. . Further, the store / recall control means 23 stores the frequency and other data registered as all evaluation target points of the registered memory 11 or the evaluation measurement memory 15 in the nonvolatile storage device 24 such as a memory card or a floppy disk, and It has a function of recalling the evaluation target points stored in the storage device 24 to the memories 11 and 15 again. 2
5 is a store recall key.

Next, the operation of the above apparatus will be described with reference to FIG. First, when the system control means 7 receives a start command, after displaying various operation menus based on the main program (step S1), the process proceeds to the next step S2 to determine whether or not there is a key input. Here, if there is a key input, it branches according to the key input and executes a predetermined program process (step S3).

The flow of program processing will be described below for each operation item. Now, in order for the operator to measure the interference noise spectrum distribution over a wide frequency range, a preliminary measurement key 1
When the system is operated, the system control means 7 receives a key signal from the preliminary measurement key 1 in step S3 and gives a command for executing the preliminary measurement program by the preliminary measurement control means 8. When a waveform other than the desired waveform is displayed on the display device 13, the preliminary measurement control means 8 deletes the waveform (step S11), and then the spectrum measurement means 9 measures a wide frequency range. Noise spectrum data (for example, FIG. 3) is sequentially captured and stored in the memory 10 (step S12). Then, the maximum level point is obtained from the noise spectrum distribution data in the memory 10 (step S13), and the maximum level point and the memory 10 are stored in advance.
If the maximum level point exceeds the standard level, the frequency fa at that level point is compared with the standard level stored by the user or the standard level according to a predetermined international standard (step S14). It is registered in the registration memory 11 as an evaluation target point (step S15). Continuing,
After obtaining the next higher level point (step S16), the process proceeds to step S14, and it is determined whether or not the level point exceeds the standard level. As a result, in FIG. 3, the frequencies fa to fc of the level points are registered in the registration memory 11,
For example, the level point shown in the figure is judged to be below the standard level, and is not registered. In this way step S14
When there is no noise spectrum that exceeds the standard level, logarithmic conversion is performed on the frequency of the noise spectrum distribution data from the memory 10 to obtain the noise spectrum distribution waveform A as shown in FIG.
S17), after storing this in the preliminary measurement memory 12, the noise spectrum distribution waveform A is read and displayed on the display device 13 (steps S18, S19). Further, the process proceeds to step S20, where the maximum level point of the waveform is designated as the initial evaluation target point, and the marker 30 is displayed at that level point (step S20). Subsequently, in step S21, it is determined whether or not the evaluation target point is changed. At this time, if the right side movement key signal is input from the marker movement key 2 by the operator's operation, the system control means 7 receives the right side movement key signal and receives the preliminary measurement control means 8 and the marker movement control means.
Then, the marker movement control means 17 changes the next evaluation target point (step S21), and observes while moving the marker 30 to the changed evaluation target point (step S2).
2). Then, when the evaluation target point is not changed, the process is terminated and returns to the menu display in step S1 to determine whether or not there is a key input (step S2).

Next, when the operator operates the evaluation measurement key 3, the system control means 7 operates the evaluation measurement key 3 in step S3.
In response to the key signal from, the evaluation measurement control means 14 gives a command to execute the evaluation measurement program. Here, when the evaluation target point is displayed on the display device 13, the evaluation measurement control means 14 tunes to the frequency of the evaluation target point, and detects the quasi-peak value or the average value of the noise spectrum of the frequency, That is, evaluation measurement is performed (steps S31 and S32).
Then, the frequency of the evaluation measurement result is logarithmically converted (step S33) and stored in the evaluation measurement memory 15 (step S34). Subsequently, evaluation measurement is performed with each frequency registered in the registration memory 11 as an evaluation target point, an evaluation measurement waveform B as shown in FIG. 5A is acquired, and this waveform B is displayed on the display device 13 ( Step S35). further,
Then, the process proceeds to step S37, where the marker 30 is displayed at the current evaluation target point (step S36). Continue to step S
Go to 37 and judge whether there is any change in the evaluation points.
At this time, when the right side movement key signal is input from the marker movement key 2 by the operator's operation, the system control means 7 receives the right side movement key signal and sends it to the evaluation measurement control means 8 and the marker movement control means 17, and the marker is moved. The movement control means 17 changes the next evaluation target point (step S3
8) Then, observe while moving the marker (a) to the evaluation target point after the change (step S39). Then, when the evaluation target point is not changed, the process is terminated and returns to the menu display in step S1 to determine whether or not there is a key input (step S2).

When the operator operates the selection key 4 to input a key signal for selecting the display content, the system control means 7 receives the key signal from the selection key 4 and causes the display content selection means 16 to execute the display content selection program. Give a command to execute. Here, the display content selection means 16 performs step S41.
At, it is determined which of the waveforms A and B or the enlarged extracted waveform C described later is to be selectively displayed. At this time, when it is determined that the waveform A should be selected from a key input (not shown), the noise spectrum distribution waveform data is read from the preliminary measurement memory 12 and displayed on the display device 13, or if the waveform A is already displayed. The display state is retained. Furthermore, the process proceeds to step S43, where the maximum level point of the waveform is designated as the initial evaluation target point, and the marker 30 is displayed at that level point as shown in FIG. 4 (a). In addition, already display device
When the waveform A is displayed on 13 and the marker 30 is attached, the state is maintained. After that, the process proceeds to step S21 and the same process as described above is performed.

Next, in step S41, when it is determined that the waveform B should be selected from the key input (not shown), the evaluation measurement waveform data B is read from the evaluation measurement memory 15 and displayed on the display device 13.
(Step S44). Further, the process proceeds to step S45, and the marker 30 is displayed at the currently designated evaluation target point as shown in FIG. 5 (a). After that, the process proceeds to step S37 and the same processing as described above is performed.

Next, when it is determined in step S41 that the enlarged extracted waveform C should be selected and displayed, for example, the first registered frequency fa is read from the registration memory 11 or an arbitrary frequency is selected from among the frequencies already registered by an operator's instruction. Readout (step S46), the noise spectrum distribution output from the spectrum measuring means 9 is measured for frequencies near the frequency fa, and the enlarged extracted waveform C is displayed on the display device 13 as shown in FIG. 6 (step S47). ). Real-time monitoring processing is performed in the vicinity of the frequency of the so-called evaluation target point. Subsequently, the process proceeds to step S48, where it is determined whether or not the evaluation target point is changed, and when it is determined that there is a change, the frequency fb of the next evaluation target point is set or an arbitrary frequency is set, and the step Similar to S47, the noise spectrum distribution near the frequency fb or any frequency is enlarged and extracted and displayed in real time (step
S50).

Next, after the menu is displayed, when the operator needs to add or delete the evaluation target points, the add key 5 or the delete key 6 is operated. First, the reason why the evaluation target points need to be added or deleted explain. For example, a VTR device is provided with components such as a local oscillator for a normal television, a microcomputer, and a logic IC inside the VTR device, and therefore, these components radiate interfering waves having different frequencies and different intensities. Therefore, when the interfering wave, that is, the noise spectrum distribution as shown in FIG.
When the frequency of is the operating clock frequency of the microcomputer of the VTR device, naturally the noise spectrum must also be the evaluation target point. Rather, the frequency
It is also possible that the level of fd and fe is small because the direction and height of the antenna are not appropriate for the direction in which these interfering waves are emitted, or that these interfering waves are changing with time. . In the conventional EMI measurement device, the frequencies fd and fe levels are within the standard, so they are not registered as evaluation points, and it is necessary to make preliminary measurements by changing the direction of the antenna again and again. Therefore, it is necessary to add the evaluation target points without performing such an operation.

On the other hand, if the operator finds that the frequency fc is the spectrum of a broadcasting station that is not related to the VTR device, it is not necessary to evaluate it as an evaluation target point, so it is necessary to exclude it from the evaluation target point. It is evaluated as an evaluation target point, and the evaluation time becomes longer accordingly. Therefore,
After the preliminary measurement, it is necessary to easily remove the unnecessary extraneous waves.

Then, when the operator operates the additional key 5 in the present apparatus, the system control means 7 causes the additional key 5 to be operated.
In response to the key input of, an instruction to execute the additional program is given to the additional control means 21 of the evaluation target point. Here, in the additional control means 21, the operator displays the third information displayed on the display device 13.
When the frequency to be added is input from the noise spectrum distribution in the figure (step S51), it is determined as the frequency of the evaluation target point to be added, and the frequency is newly registered in the registration memory 11 as the evaluation target point (step S51). S52).

On the other hand, when the operator operates the delete key 6, the delete control means 22 executes the evaluation target point delete program. That is, the operator specifies and inputs the frequency of the unnecessary noise spectrum among the frequencies already registered in the registration memory 11 from the noise spectrum distribution waveform A or the evaluation measurement waveform B of FIG. 3 displayed on the display device 13. Then, the frequency can be deleted from the registration memory 11 (step S61) (step S62).

Further, the operation items of the evaluation target point store and the evaluation target point recall are displayed on the menu display, and the evaluation target point store or the evaluation target point recall can be performed based on the operation items. In this evaluation target point store, the system control means 7 sends a recall control signal to the store / recall control means 23 in response to the store key signal from the store / recall key 25, whereby the store / recall control means 23 sends predetermined data. This is a function of executing a read operation to read the contents of, for example, the registration memory 11 or the evaluation measurement memory 15 and store them in the non-volatile storage device 24 (step S63). Recall key signal to recall the data stored in the non-volatile storage device 24 to the memories 11 and 15 and display it on the display device 13 (step S64) to newly execute and register preliminary measurement and evaluation measurement. Can be omitted, and the evaluation measurement can be performed again at exactly the same frequency as the frequency at which the evaluation measurement was previously performed.

Therefore, according to the configuration of the above embodiment, the noise spectrum distribution in the vicinity of the frequency of the evaluation target point registered after the preliminary measurement or after the evaluation measurement is enlarged is enlarged and displayed.
Since it can be displayed in real time on 13, it is possible to easily know whether or not it is unnecessary extraneous liquid, and to grasp the state of the noise spectrum more accurately. Further, since the display state of the noise spectrum distribution in the wide frequency range can be returned after the end of the real-time measurement, it is possible to determine which noise spectrum of the preliminary measurement end display corresponds to. Further, since the noise spectrum distribution waveform, the evaluation measurement waveform, and the enlarged waveform in the vicinity of the frequency of a certain evaluation target point can be selected and displayed as appropriate, the operator can appropriately observe the desired waveform and perform quick evaluation. Furthermore, by attaching a marker to the evaluation target point for each measurement and moving the marker to another required evaluation target point by the marker movement control means 17, the noise spectrum to be evaluated can be easily specified, and other noise Comparison with the spectrum can be easily performed.

Furthermore, it is possible to add more required evaluation points to the evaluation points already registered in the registration memory 11, and delete unnecessary evaluation points to ensure that only the necessary frequencies are evaluated without omission. Moreover, if the operator knows the frequency to be evaluated and measured, it is possible to skip the preliminary measurement and perform real-time monitor processing by expansion extraction and evaluation measurement. The frequency can be evaluated quickly. Furthermore, by storing the data stored in each of the memories 11 and 15 in a non-volatile storage device or making it recallable, important data at the final evaluation target point can be reliably saved even after the power of the device is turned off, and , The same evaluation points as before can be reproduced and evaluated.

〔The invention's effect〕

As described above, according to the present invention, the following various effects are exhibited.

First, in claim 1, the desired measurement result data can be promptly and surely taken out and displayed, whereby the evaluation time can be shortened. In addition, a certain evaluation target point can be evaluated in detail by performing real-time monitor measurement.

Next, in claim 2, unnecessary liquid such as external waves can be easily removed, and necessary evaluation points can be added to perform an appropriate evaluation. From this point as well, the evaluation time can be shortened. Can be planned.

Further, in claim 3, the obtained evaluation target points are stored in an external non-volatile storage device, and the evaluation target points are used when necessary, so that preliminary measurement and the like can be omitted.

[Brief description of drawings]

1 to 6 are shown for explaining the embodiment of the device of the present invention. FIG. 1 is a block diagram showing the function of the device of the present invention, and FIG. 2 is a series of operation flow of the device of the present invention. FIG. 3, FIG. 3 is a noise spectrum distribution diagram in a wide frequency range, FIG. 4 is a diagram for explaining selection of an evaluation target point and a moving state of the marker, and FIG. 5 is a result of evaluation measurement and a moving state of the marker. 6 and 6 are enlarged views of the noise spectrum distribution near the frequency of a certain evaluation point, FIG. 7 is a diagram showing the operation flow of the conventional device, and FIG. 8 (a) is a noise spectrum distribution diagram of the conventional device. FIG. 8 (b) is a diagram showing a state of the evaluation measurement result. 1 ... Preliminary measurement key, 2 ... Marker movement key, 3 ... Evaluation measurement key, 4 ... Selection key, 5 ... Selection key, 6 ...
Delete key, 7 ... system control means, 8 ... preliminary measurement control means, 9 ... spectrum measurement means, 10 ... memory,
11 …… Registered memory, 12 …… Preliminary measurement memory, 13 …… Display device, 14 …… Evaluation measurement control means, 15 …… Evaluation measurement memory, 16 …… Display content selection control means, 17 …… Marker movement Control means, 21 ... Additional control means, 22 ... Delete control means,
23 ... Store / recall control means, 24 ... nonvolatile storage device.

Claims (3)

[Claims] 1. An EMI measuring device that measures a noise spectrum distribution in a wide frequency range and evaluates the noise spectrum, compares the measured noise spectrum with a predetermined standard level, and the noise spectrum is equal to or higher than the standard level. When the frequency of the noise spectrum is
Preliminary measurement control for storing in the second memory (12) and displaying on the display device (13) the noise spectrum distribution waveform data obtained by logarithmically converting the noise spectrum distribution in the wide frequency range, which is registered in 1). By means of the means (8) and the preliminary measurement control means, the respective frequencies registered in the first memory are sequentially subjected to the evaluation and measurement, and the obtained evaluation measurement waveform data is stored in the third memory (15).
An evaluation measurement control means (14) which is stored in the display device and displayed on the display device, preliminary measurement waveform data stored in the second memory in response to a display content selection key, and evaluation stored in the third memory. Display content selection control means (16) for selecting and displaying either the measured waveform data or the expanded waveform data obtained by measuring the noise spectrum in the vicinity of the frequency to be evaluated, which is registered in the first memory. A preliminary measurement waveform displayed by the preliminary measurement control unit, an evaluation measurement waveform displayed by the evaluation measurement control unit, or a preliminary measurement waveform selected and displayed by the display content selection control unit, or an evaluation measurement waveform display An EMI measuring device characterized by further comprising a marker movement control means (17) for attaching a marker to a desired evaluation target point and moving the marker at times. . 2. An evaluation target point adding means (21) for additionally registering a frequency as an evaluation target point in a first memory, and an arbitrary frequency selected from the frequencies as the evaluation target points registered in the first memory. The EMI measuring device according to claim 1, further comprising: evaluation target point deleting means (22) for specifying and deleting a frequency. 3. A non-volatile memory device (24), and the non-volatile memory device stores an evaluation target point in a first memory and reproduces the stored evaluation target point in the first memory. Store recall control means for
Alternatively, the EMI measuring device according to claim 2.