JP7556538B2 - Jamming Radio Wave Measurement System - Google Patents

Description

The present invention relates to a system and method for measuring jamming signals, and in particular to a system and method for measuring jamming signals from an electrical device to be measured (EUT: Equipment Under Test) at an open site.

Electromagnetic waves (jamming waves) are emitted as unwanted noise from electrical equipment such as office automation equipment, household electrical appliances, and industrial electrical equipment. These jamming waves can have adverse effects on other electrical equipment and systems, such as causing malfunctions, so EMC (Electromagnetic Compatibility) evaluations are conducted on electrical equipment. EMC evaluations measure the amount of jamming waves emitted from electrical equipment. In recent years, there has been a trend that measurement regulations cannot be met unless the equipment is highly functional in EMC evaluations, and investment in evaluation performance is increasing.

Conventionally, two methods of measuring jamming signals are known: measurement in an anechoic chamber and measurement at an open site. Measurement in an anechoic chamber uses an electromagnetically shielded measurement room, and the jamming signals of the EUT are measured in an environment that is not affected by external radio waves. This method is therefore excellent in terms of the accuracy of detecting jamming signals. However, there are problems with the construction of an anechoic chamber such as a 10m anechoic chamber, which requires a large amount of money, such as a vast site and a building to house the anechoic chamber.

On the other hand, open-site measurements do not require large-scale equipment because they measure EUT jamming signals in a natural space. However, instead of using equipment to block external radio waves, work is required to distinguish between external radio waves and jamming signals.

For example, a measurement method described in Patent Document 1 is known as an open-site measurement. FIG. 7 shows a schematic diagram of a jamming measurement system described in Patent Document 1. The measurement system 15 shown in FIG. 7 is a system for measuring jamming radio waves emitted from an EUT 14. The measurement system 15 has a measurement antenna 11 arranged at a predetermined distance _La from the EUT 14, a long-distance antenna 12 arranged farther away than the measurement antenna 11, and a detection device 13 to which radio wave information of radio waves received by each of the antennas 11 and 12 is input. The long-distance antenna 12 is arranged at a distance _Lb at which it is hardly affected by jamming radio waves emitted from the EUT 14. In this measurement system 15, the radio waves received by the measurement antenna 11 and the long-distance antenna 12 are measured with the power of the EUT 14 turned on, and the detection device 13 compares the measurement results to measure jamming radio waves of the EUT 14.

JP 2001-296322 A

The measurement system of Patent Document 1 above makes it possible to measure jamming radio waves even at open sites. However, because external radio waves are detected as broadband, continuous pulsed waves, it is conceivable that even with the measurement system of Patent Document 1, the jamming radio waves will be buried in the external radio waves, making detection difficult.

The present invention was made in consideration of these circumstances, and aims to provide a jamming radio wave measuring system and measuring method that can accurately detect jamming radio waves even at open sites.

The jamming wave measurement system of the present invention is a measurement system that measures jamming waves emitted from a measurement object at an open site, and the measurement system includes a measurement antenna located at a distance specified by a standard from the measurement object, a short-distance antenna located closer to the measurement object than the measurement antenna, a long-distance antenna located farther from the measurement object than the measurement antenna, an operation control unit that operates each of the antennas to receive radio waves while the measurement object is in operation, and a detection device to which radio wave information of the radio waves received by each of the antennas is input, and the detection device is characterized by having an identification unit that identifies the jamming waves based on the radio wave information of the radio waves received by the short-distance antenna and the radio wave information of the radio waves received by the long-distance antenna, and an analysis unit that analyzes the jamming waves from the radio wave information of the radio waves received by the measurement antenna based on the identified jamming waves.

The measurement system includes a database in which radio wave information of radio waves received by the long-distance antenna is stored for each time based on Universal Time when the object to be measured is not in operation, and the identification unit identifies the jamming radio waves based on the radio wave information stored in the database in addition to the radio wave information of radio waves received by the short-distance antenna and the radio wave information of radio waves received by the long-distance antenna. In this specification, a state in which the object to be measured is in operation refers to a state in which the power of the object to be measured is on, and a state in which the object to be measured is not in operation refers to a state in which the power of the object to be measured is off.

The operation control unit is characterized in that, when the object to be measured is in operation, it operates each of the antennas to receive radio waves at the same time as the time associated with each piece of radio wave information stored in the database.

The measurement antenna is installed at a distance of at least 3 m as specified by the standard, and the short-range antenna is placed within 1 m of the object to be measured.

The long-distance antenna has multiple antennas each spaced at an equal distance from the object to be measured, and the identifying unit uses average radio wave information obtained by averaging the radio wave information received by each antenna.

The jamming wave measuring method of the present invention is a method for measuring jamming waves emitted from an object to be measured at an open site using a measuring system, the measuring system including a measuring antenna arranged at a distance specified by a standard from the object to be measured, a short-range antenna arranged closer to the object to be measured than the measuring antenna, and a long-range antenna arranged farther from the object to be measured than the measuring antenna, and the measuring method includes a measuring step of operating each antenna to receive radio waves while the object to be measured is in operation, a specifying step of identifying the jamming waves based on radio wave information of the radio waves received by the short-range antenna and radio wave information of the radio waves received by the long-range antenna, and an analysis step of analyzing the jamming waves from the radio wave information of the radio waves received by the measuring antenna based on the identified jamming waves.

The jamming radio wave measuring system and method of the present invention includes a measuring antenna arranged at a distance from the object to be measured that is specified by the standard, a short-distance antenna arranged closer than the measuring antenna, and a long-distance antenna arranged farther than the measuring antenna. The jamming radio waves emitted from the object to be measured are stronger the closer to the object to be measured and weaker the farther away they are, so by providing a short-distance antenna closer than the regular measuring antenna, it is possible to reliably receive the jamming radio waves from the object to be measured at a certain level of strength. In addition, the short-distance antenna receives external radio waves along with the jamming radio waves. On the other hand, the long-distance antenna mainly receives external radio waves. Therefore, by using the radio wave information of the radio waves received by the short-distance antenna and the long-distance antenna, it is possible to reliably identify the jamming radio waves. Furthermore, after grasping the characteristics of the identified jamming radio waves (such as frequency and field strength), the jamming radio waves are analyzed from the radio wave information of the radio waves received by the measuring antenna, so that the jamming radio waves can be detected with high accuracy.

The measurement system also includes a database that stores radio wave information of radio waves received by a long-distance antenna for each time based on Universal Time when the object to be measured is not in operation, and the identification unit further uses the radio wave information stored in the database to identify jamming radio waves. This allows for the inclusion of radio wave information of external radio waves when the object to be measured is not in operation, enabling more accurate detection of jamming radio waves.

It is believed that external radio waves, such as AM modulated radio waves and FM modulated radio waves emitted from general broadcasting stations, are often emitted at the same time each day. Taking this into consideration, the operation control unit operates each antenna to receive radio waves at the same time as the time linked to each radio wave information stored in the database, making it easier to identify external radio waves and ultimately improving the accuracy of detecting jamming radio waves.

1 is a schematic diagram of one embodiment of a jamming wave measurement system according to the present invention; FIG. 2 is a block diagram of the measurement system of FIG. 1 . FIG. 2 is a diagram showing an example of a waveform of a radio wave received by an antenna. FIG. 4 is a diagram showing peak intensities for each frequency of radio waves received by each antenna. 4 is a flowchart showing an example of a method for measuring jamming radio waves according to the present invention. 1 is a schematic diagram of another embodiment of the jamming wave measurement system of the present invention; FIG. FIG. 1 is a schematic diagram showing the configuration of a conventional jamming wave measurement system.

The jamming radio wave measurement system of the present invention will be described with reference to FIG. 1. The measurement system 10 shown in FIG. 1 is a system that measures jamming radio waves emitted from an EUT 5 at an open site. Generally, natural spaces are filled with a variety of external radio waves, such as white noise, AM-modulated radio waves and FM-modulated radio waves emitted from general broadcasting stations, SSB-modulated radio waves emitted from military facilities, and digitally modulated radio waves. The measurement system 10 can identify and measure jamming radio waves emitted from an EUT 5 without being affected by these external radio waves.

As shown in Fig. 1, the measurement system 10 includes a measurement antenna 1 arranged at a distance _L1 from the EUT 5, a short-distance antenna 2 arranged closer to the EUT 5 than the measurement antenna 1, a long-distance antenna 3 arranged farther from the EUT 5 than the measurement antenna 1, and a detection device 4 to which radio wave information of radio waves received by each of the antennas 1, 2, and 3 is input. The EUT 5 is an electrical device for measuring jamming waves, and is placed on a rotatable turntable 6. The turntable 6 is used to detect whether the jamming waves emitted from the EUT 5 have directionality. If the jamming waves have directionality, the direction of the EUT 5 relative to the measurement antenna 1 is adjusted to the direction in which the jamming waves are strongest.

The measurement antenna 1 is a wideband antenna capable of receiving radio waves in a certain frequency band required for measuring jamming waves from the EUT 5. For example, a log periodic antenna defined in the EMC standard or the like can be used for the measurement antenna 1. The measurement antenna 1 is installed at a distance L ₁ from the EUT 5. This distance L ₁ is the measurement distance of jamming waves from the EUT 5 and is defined by the EMC standard or the like. In general, the distance L ₁ is set to any one of 3 m, 10 m, or 30 m. The measurement antenna 1 is also arranged so as to be movable up and down by a support mechanism. The height of the measurement antenna 1 is adjusted, for example, between 1 m and 4 m depending on the electric field strength of the jamming waves to be received.

The short-distance antenna 2 is an antenna for measuring jamming radio waves of the EUT 5 and external radio waves, and is intended to grasp the frequency of jamming radio waves in the operating state of the EUT 5 in particular. The short-distance antenna 2 is preferably installed as close to the EUT 5 as possible so that jamming radio waves of the EUT 5 can be reliably detected. The distance _L2 is preferably within 1 m, more preferably within 0.5 m. The position at which the short-distance antenna 2 is installed is not particularly limited, but it is preferably installed at a position perpendicular to the line segment connecting the EUT 5 and the measurement antenna 1 in a plan view of the system. In addition, the height of the short-distance antenna 2 is preferably lower than the height of the measurement antenna 1.

The long-distance antenna 3 is an antenna mainly for measuring external radio waves, and is preferably installed at a position where it is hardly affected by jamming radio waves emitted from the EUT 5. The distance _L3 depends on the distance _L1 , but is, for example, 10 m or more, preferably 30 m or more, and more preferably 50 m or more. A specific range of the distance _L1 is, for example, 30 m to 200 m. The position at which the long-distance antenna 3 is installed is not particularly limited, but it is preferably installed on an extension of a line segment connecting the EUT 5 and the measurement antenna 1 in a plan view of the system. In addition, the height of the long-distance antenna 3 is preferably higher than the height of the measurement antenna 1.

In FIG. 1, it is preferable that each of the antennas 1 to 3 is located at a distance (e.g., several kilometers) away from the source of external radio waves, such as a general broadcasting station, so that they can be regarded as the same. In this way, the electric field strength of the external radio waves received by each of the antennas 1 to 3 can be regarded as being of the same strength, in theory. There are no particular limitations on the antennas that can be used for the short-range antenna 2 and the long-range antenna 3, and log periodic antennas, etc., can be used.

Detection device 4 is mainly composed of a microcomputer including a known CPU, ROM, RAM, etc. Detection device 4 is connected to each of antennas 1 to 3 by wire or wirelessly, and radio wave information of radio waves received by each of antennas 1 to 3 is input. Here, the connection state between each of antennas 1 to 3 and detection device 4 will be explained using the block diagram in Figure 2.

As shown in FIG. 2, each of the antennas 1 to 3 is connected to a receiver and a control device that controls the operation of the receiver. The short-range antenna 2 and the long-range antenna 3 are each provided with a well-known software defined radio (SDR) as a receiver. Each control device is mainly composed of a microcomputer that includes a well-known CPU, ROM, RAM, etc. Each control device is connected to the detection device 4 so that they can communicate with each other.

By using a software radio as the receiver, it is possible to switch between the communication functions of several different wireless communication methods using software inside the radio. In addition, it is possible to flexibly provide almost the same functions as an expensive EMI (Electromagnetic Interference) receiver by changing the software, which helps to reduce costs. Specifically, by fixing the receiver hardware and designing the receiving bandwidth, filters for isolating signals, etc. using software, it is possible to support new standards, etc.

In FIG. 2, the measurement system 10 includes a database 7 that stores radio wave information of radio waves measured at an open site when the EUT is not in operation. The database 7 stores radio wave information of radio waves in a specific frequency band (e.g., a range of 30 MHz to 1000 MHz) received by the long-distance antenna 3 at each time based on Greenwich Mean Time (GMT). Each time based on Greenwich Mean Time refers to, for example, a fixed time (00:00, 00:10, etc.) based on the clock of the OS software of a current personal computer unified by Greenwich Mean Time. The database 7 stores each time in association with the radio wave information received at that time. Note that the database 7 may also store radio wave information of radio waves received by the short-distance antenna 2.

The database 7 may be connected to each control device and detection device 4 via a network, or each control device and detection device 4 may have the database 7. A network refers to an electronic communication line capable of sending and receiving data, such as a wired LAN, a wireless LAN, a WAN, or the Internet. Storing radio wave information in a server or memory unit means storing it in a specified format in a storage medium such as a semiconductor memory or a magnetic disk of a server or electronic information terminal.

Radio waves measured at an open site when the EUT is not in operation do not include jamming radio waves emitted when the EUT is in operation, and can therefore be identified as external radio waves. In this way, a database of external radio waves can be constructed by continuously accumulating radio wave information (strength, type of modulation, etc.) of external radio waves. The accuracy of detecting jamming radio waves can be improved by using the accumulated radio wave information of external radio waves to identify jamming radio waves. In addition, public information 8 such as the frequency and modulation method of external radio waves that is publicly available on the Internet or the like may be input to the database 7, and radio wave information of radio waves received at other antenna sites 9 may be input via a network.
Examples of the other antenna sites 9 include other test sites where jamming radio waves are measured at open sites. The locations of the other antenna sites 9 are not particularly limited, and they can be installed anywhere in the world, including Japan. This allows for centralized management of radio wave information on jamming radio waves from all over the world. For example, by creating a database of radio wave information on jamming radio waves from all over the world, even if an ionosphere called a sporadic E layer occurs suddenly or locally, it can be used to identify jamming radio waves reflected by the ionosphere. In addition, it is preferable that the input radio wave information is radio wave information on radio waves in a specified frequency band received by the antennas of each antenna site 9 at each time based on Universal Time. Note that the radio wave information on radio waves received at the other antenna sites 9 may be directly input to the detection device 4.

By using the database 7, it is possible to construct a database that covers a wide range of radio wave noise in natural spaces. The stored radio wave information includes, for example, information on undisclosed radio waves and foreign broadcast radio waves. In other words, by using the database 7, a data darkroom can be created in the server. By using the data darkroom, it is possible to accurately determine external radio waves, which in turn leads to improved accuracy in detecting jamming radio waves. It is also expected that ultimately, by using the radio wave information in the database 7 and the radio wave information of the radio waves received by the measurement antenna 1, it will be possible to detect jamming radio waves. The information contained in the database may be made public via the Internet, etc., or may be provided to users.

In measuring jamming radio waves, while the EUT is in operation, each of the antennas 1 to 3 is operated to receive radio waves. In the configuration of FIG. 2, each control device corresponds to the "operation control unit" in the present invention. The function of the operation control unit may be provided in the detection device. The measurement start time of each of the antennas 1 to 3 is started simultaneously according to the world standard time. In particular, it is preferable to operate each of the antennas 1 to 3 to receive radio waves at the same time as the time linked to each radio wave information stored in the database 7. For example, if radio wave information at 00:00 on a given day is stored in the database 7, radio waves are received by each of the antennas 1 to 3 at the same time, 00:00, on another day (measurement day). Jamming radio waves with the same radio wave characteristics are often emitted at the same time on each day, making it easier to determine jamming radio waves.

The measurement range of each of the antennas 1 to 3 is set to the same frequency band (for example, a range from 30 MHz to 1000 MHz), and radio waves of the same frequency are measured simultaneously by each antenna. Through this measurement, external radio waves and jamming radio waves from the EUT are received by the measurement antenna 1 and the short-distance antenna 2. External radio waves are also received by the long-distance antenna 3 at approximately the same time as the short-distance antenna 2, etc. The long-distance antenna 3 mainly receives external radio waves. In the present invention, by performing measurements simultaneously by each of the antennas 1 to 3, the external radio waves become the same, and it is possible to accurately determine the external radio waves.

Figure 3 shows an example of the waveform of radio waves received by an antenna. In Figure 3, the horizontal axis represents frequency, and the vertical axis represents the electric field strength for each frequency. By performing this measurement at specified time intervals or continuously, a three-dimensional graph including the time axis can be obtained. Once the measurement by each antenna is completed, the radio wave information is transferred to the detection device 4.

Returning to FIG. 2, the detection device 4 has a memory unit 4a, a determination unit 4b, and an analysis unit 4c. The radio wave information D1 to D3 of the radio waves received by each of the antennas 1 to 3 is input and stored in the memory unit 4a. In FIG. 2, the radio wave information of the radio waves received by the measurement antenna 1 is D1, the radio wave information of the radio waves received by the short-range antenna 2 is D2, and the radio wave information of the radio waves received by the long-range antenna 3 is D3. This radio wave information includes the frequency, bandwidth, field strength, modulation type (e.g., AM modulation, FM modulation, SSB modulation, digital modulation), etc. for all the radio waves received by each antenna. In other words, the memory unit 4a stores the radio wave information obtained by scanning the entire measurement range once or multiple times with each antenna as measurement data. Note that the radio wave information may include a waveform of a certain frequency width as analog data.

The identification unit 4b identifies jamming radio waves from the EUT 5 based on radio wave information D2 of the radio waves received by the short-distance antenna 2, radio wave information D3 of the radio waves received by the long-distance antenna 3, and radio wave information stored in the database 7. Specifically, while referring to the radio wave information stored in the database 7, the identification unit 4b identifies jamming radio waves from the EUT 5 by calculating the difference between the data of electric field strength for each frequency included in D2 and the data of electric field strength for each frequency included in D3. This identification of jamming radio waves will be explained using FIG. 4.

Figure 4 shows an example of the waveform of radio waves received by each antenna. For convenience, Figure 4 uses a two-dimensional graph with frequency on the horizontal axis and field strength for each frequency on the vertical axis for explanation. Also, although explanations are given using radio wave waveforms, in reality jamming radio waves are identified using the field strength (peak strength) for each frequency. Measurements for each antenna are performed at the same start time.

In the identification unit, first, an external radio wave is determined based on the radio wave information D2, D3 and the radio wave information in the database. Although the short-distance antenna and the long-distance antenna are at significantly different distances from the EUT, the distance is not significantly different from the source of the external radio wave, so the electric field strength of the external radio wave is almost the same in D2 and D3. Therefore, a peak that exists at the same frequency position with the same electric field strength can be determined to be an external radio wave. Specifically, if the value obtained by subtracting the peak strength of D3 from the peak strength of D2 at the same frequency is within a predetermined range, the peak can be determined to be an external radio wave. Furthermore, the external radio wave obtained from the difference can be compared with the radio wave information of the external radio wave stored in the database 7, so that the determination of the external radio wave can be made more accurate. Even if there is an external radio wave that is the same as or has a similar radio wave format as the jamming radio wave, it is easier to determine the excluded radio wave by using the radio wave information in the database 7. Then, the external radio wave is determined for all frequencies within the measurement range, and the radio waves excluding the external radio waves from D2 are identified as jamming radio waves.

For example, in FIG. 4, peak group Q1 and Q2 in D2, which exist at the same frequency position as D3 and have the same electric field strength, are determined to be external radio waves. Peak P in D2, which is a peak other than peak groups Q1 and Q2, is identified as jamming radio waves. In FIG. 4, peak P detected only in D2 is identified as jamming radio waves.

It should be noted that, not limited to the example in Figure 4, jamming radio waves can be identified even when the peaks of external radio waves and jamming radio waves overlap. Jamming radio waves emitted from the EUT are strong near the EUT and become weaker the farther away the EUT is, so even if jamming radio waves overlap at the same frequency as external radio waves, the peak strength of the jamming radio waves will be large at D2 and the peak strength of the jamming radio waves will be small or barely detectable at D3. Therefore, if the difference in peak strength between D2 and D3 at the same frequency is equal to or greater than a predetermined threshold, jamming radio waves can be identified as containing jamming radio waves.

In FIG. 2, after the jamming radio waves are identified by the identification unit 4b, the analysis unit 4c analyzes the jamming radio waves using the radio wave information D1 of the radio waves received by the measurement antenna 1. The analysis unit 4c analyzes the frequency, field strength, modulation type, etc. of the jamming radio waves, which are unwanted radiation. These are illustrated as in a standard to determine whether they are within regulations. For example, in FIG. 4, an analysis is performed on peak P at D1. The modulation type of the jamming radio waves radiated from the EUT is thought to be mainly AM modulation due to voltage fluctuations caused by the load when devices such as the CPU are operating, or FM modulation influenced by voltage fluctuations in the CPU's oscillator circuit.

In this way, with the measurement system 10 shown in FIG. 2, it is possible to accurately identify jamming radio waves by using radio wave information of radio waves received by the short-distance antenna 2 and the long-distance antenna 3. Furthermore, by measuring external radio waves under normal circumstances with the SDR and control device and using this data, it is possible to more reliably distinguish (separate) jamming radio waves from those from the EUT. Then, by fully understanding the characteristics of the identified jamming radio waves and then analyzing the radio wave information based on the regular measurement antenna, it is possible to accurately extract the jamming radio wave information from among the radio waves that contain jamming radio waves and external radio waves. Furthermore, since measurements using the three types of antennas are performed simultaneously and in parallel, it is possible to accurately identify external radio waves even when the strength of the external radio waves fluctuates, which ultimately leads to improved accuracy in measuring jamming radio waves.

The jamming wave measuring method of the present invention comprises at least four steps (a) to (d) shown in FIG. 5. That is, it comprises (a) an installation step of installing the EUT, (b) a measurement step of receiving radio waves with each antenna, (c) an identification step of identifying jamming waves, and (d) an analysis step of analyzing jamming waves. Each step will be described with reference to FIG. 1.

First, the EUT 5 is placed on the turntable 6, and the power supply of the EUT 5 is turned on in this state (step (a)). This causes the EUT 5 to start a predetermined operation, and the EUT 5 emits jamming radio waves. Then, the antennas 1 to 3 are operated simultaneously to receive radio waves in the same frequency band (step (b)). After the measurement, the jamming radio waves are identified based on the radio wave information of the radio waves received by the short-range antenna 2 and the radio wave information of the radio waves received by the long-range antenna 3, specifically from the difference between these (step (c)). Then, based on the identified jamming radio waves, the jamming radio waves are analyzed from the radio wave information of the radio waves received by the measurement antenna 1 (step (d)). This allows the jamming radio waves of the EUT 5 to be accurately measured, distinguished from external radio waves, even at an open site. Note that in a configuration using a database of external radio waves, radio wave information of external radio waves is acquired in advance by the long-range antenna 3, etc., prior to step (a).

The measurement system of the present invention is not limited to the form shown in FIG. 1, and may adopt the form shown in FIG. 6, for example. In the measurement system 10' shown in FIG. 6, the configuration of the long-distance antenna is different from that of the measurement system 10 shown in FIG. 1. Specifically, the measurement system 10' has a plurality of long-distance antennas 3a, 3b, and 3c as long-distance antennas. Each of the long-distance antennas 3a to 3c is installed, for example, at an equal distance L ₃ from the EUT 5. These long-distance antennas 3a to 3c mainly receive external radio waves. Then, by using average radio wave information obtained by averaging the radio wave information of the radio waves received by each of the long-distance antennas 3a to 3c, the jamming radio waves can be identified more accurately.

The number of long-distance antennas can also be set to the number of users who use this measurement system. In this case, the number of long-distance antennas can become extremely large. In such a configuration, some of the long-distance antennas can be used to measure jamming radio waves, and some or all of the long-distance antennas can be used to measure external radio waves for the database. This is believed to help make more accurate measurements of jamming radio waves.

Further, a short-distance antenna may be further added to the embodiment of Fig. 1 or the embodiment of Fig. _6. For example, a first short-distance antenna and a second short-distance antenna are provided as the short-distance antennas, each of which is separated by an equal distance L2 from the EUT 5. The first short-distance antenna and the second short-distance antenna are preferably installed so as to face each other with the EUT 5 therebetween. These short-distance antennas receive jamming radio waves from the EUT 5 and external radio waves. In this case, it is also preferable to identify jamming radio waves using average radio wave information obtained by averaging the radio wave information of the radio waves received by the first short-distance antenna and the second short-distance antenna, respectively.

In addition, in the measurement system of the present invention, a tool can be provided that can turn the power of the EUT on and off by sending a special signal from a detection device or the like. This will play an important role in the measurement work currently being done to clearly distinguish whether or not jamming radio waves are being emitted from the EUT. It is also expected that in the future, this will play a major role in the development of SDR control software that utilizes AI technology, and in EMC evaluations that utilize various data accumulated as experience.

The measurement system of the present invention can accurately detect jamming signals even at open sites, so it does not require equipment such as an anechoic chamber and can be widely used to measure jamming signals in EMC evaluations.

REFERENCE SIGNS LIST 1 Measurement antenna 2 Short-range antenna 3, 3a, 3b, 3c Long-range antenna 4 Detection device 4a Memory unit 4b Identification unit 4c Analysis unit 5 EUT
6 Turntable 7 Database 8 Public information 9 Other antenna sites 10, 10' Measurement system

Claims (4)

A measurement system for measuring jamming radio waves emitted from a measurement target at an open site, comprising:
The measurement system includes a measurement antenna arranged at a distance defined by a standard from the object to be measured, a short-distance antenna arranged closer to the object to be measured than the measurement antenna, and a long-distance antenna arranged farther from the object to be measured than the measurement antenna, an operation control unit that operates each of the antennas to receive radio waves while the object to be measured is in operation, and a detection device to which radio wave information of the radio waves received by each of the antennas is input,
The detection device has an identification unit that identifies the jamming radio waves based on radio wave information of the radio waves received by the short-distance antenna and radio wave information of the radio waves received by the long-distance antenna, and an analysis unit that analyzes the jamming radio waves from the radio wave information of the radio waves received by the measurement antenna based on the identified jamming radio waves,
the measurement system includes a database in which radio wave information of radio waves received by the long-distance antenna is stored for each time based on Universal Time when the measurement target is not in operation;
A jamming radio wave measurement system characterized in that the identification unit identifies the jamming radio waves based on radio wave information stored in the database, in addition to radio wave information of the radio waves received by the short-range antenna and the long-range antenna . The jamming radio wave measurement system described in claim 1, characterized in that the operation control unit, when the object to be measured is in operation, operates each antenna to receive radio waves at the same time as the time linked to each radio wave information stored in the database. The jamming radio wave measurement system according to claim 1 or 2, characterized in that the distance specified by the standard at which the measurement antenna is installed is at least 3 m, and the short-range antenna is positioned within 1 m of the object to be measured. A measurement system for measuring jamming radio waves emitted from a measurement target at an open site, comprising:
The measurement system includes a measurement antenna arranged at a distance defined by a standard from the object to be measured, a short-distance antenna arranged closer to the object to be measured than the measurement antenna, and a long-distance antenna arranged farther from the object to be measured than the measurement antenna, an operation control unit that operates each of the antennas to receive radio waves while the object to be measured is in operation, and a detection device to which radio wave information of the radio waves received by each of the antennas is input,
The detection device has an identification unit that identifies the jamming radio waves based on radio wave information of the radio waves received by the short-distance antenna and radio wave information of the radio waves received by the long-distance antenna, and an analysis unit that analyzes the jamming radio waves from the radio wave information of the radio waves received by the measurement antenna based on the identified jamming radio waves,
The jamming radio wave measurement system is characterized in that the long-distance antenna has multiple antennas each located at an equal distance from the object to be measured, and average radio wave information obtained by averaging the radio wave information of the radio waves received by each antenna is used in the identification unit.

Images