JP2012194090A - Noise measurement method, noise measurement device, and noise measurement program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noise measurement method, noise measurement device, and noise measurement program for measuring a radiated noise accurately in a short time.SOLUTION: A noise measurement device calculates each time-domain spectrum of a noise in a focused frequency band; calculates an average spectrum in the focused frequency band; extracts, on the basis of the average spectrum, frequency points at the maximum noise levels in a plurality of respective divided frequency bands into which the focused frequency band is divided; measures noise levels at the extracted frequency points at the maximum noise levels in the plurality of respective divided frequency bands; and sets the maximum value among the measured plurality of noise levels as a noise level in the focused frequency band.

Description

  The present invention relates to a noise measurement method for measuring radiation noise, a noise measurement device, and a noise measurement program.

  ITE (Information Technology Equipment, information processing equipment) is required to comply with EMI regulations (Electro-Magnetic Interference) in each country, and EMI measurement is performed in equipment development.

  Based on the international standard CISPR, a QP (quasi-peak) is measured with a measuring device called a receiver in the range of 30 MHz to 1 GHz. If the standard cannot be cleared, the product cannot be shipped. Thus, clearing this standard is a critical factor that greatly affects the quality of the product itself.

  In the QP measurement, in order to measure the range of 30 MHz to 1 GHz with the receiver, the measurement is repeated while shifting the frequency by a bandwidth of 0.12 MHz, which is unrealistic because it takes several hundred hours. For this reason, a simple method is generally used in which the spectrum is measured in advance in a short time using a measuring instrument called a spectrum analyzer, and only the frequency that seems to have a high noise level is extracted and measured by the receiver. Yes. However, this method sometimes misses the maximum value and fails to pass the standard in the test results, and may follow up with additional measures.

  Originally, if it is possible to accurately detect the maximum frequency from the spectrum, it is desirable to measure the frequency only once by the receiver. However, although the spectrum has a wide frequency range, it is difficult to detect an accurate frequency from the spectrum because the resolution is rough with about 500 to 1000 dots.

  For this reason, in the past, the maximum value was detected while gradually changing the frequency of the receiver in the vicinity of the frequency considered to be the maximum value. However, there are problems of measurement time and workability, which is a big problem.

  Here, there are two types of noise: broadband band noise and narrow band noise. In recent years, in order to reduce noise, a technique called spread spectrum is widely used for circuit signals. The noise generated from a circuit using this frequency spread is broadband noise whose frequency range has spread to several tens of MHz. This broadband noise is noise having characteristics distributed over a wide frequency range, and it is necessary to detect the maximum value while gradually changing the frequency of the receiver many times. For this reason, in broadband noise, it is difficult to detect the maximum frequency from the spectrum, and it is often necessary to take additional measures by overlooking the maximum value.

  Here, conventionally, a method for discriminating between broadband noise and narrowband noise has been proposed, but it is desired to perform highly accurate measurement in a short time after the broadband noise is identified.

JP 2005-257285 A Special table 2004-514143 gazette JP-A-3-205571

  An object of the noise measurement method, the noise measurement device, and the noise measurement program disclosed in the present disclosure is to measure radiation noise with high accuracy and in a short time.

The noise measurement method disclosed in the present disclosure includes the following steps.
(1) The average spectrum of the frequency band of interest is calculated by calculating the spectrum of each time domain of the noise of the frequency band of interest.
(2) Based on the average spectrum, the frequency point of the maximum noise level of each of a plurality of divided frequency bands obtained by dividing the frequency band of interest into a plurality is extracted.
(3) The noise level at the frequency point of the maximum noise level extracted for each of the plurality of divided frequency bands is measured.
(4) The maximum value among the plurality of measured noise levels in the plurality of divided frequency bands is set as the noise level of the target frequency band.

  In addition, the noise measurement device disclosed herein includes an antenna, a spectrum analyzer, a receiver, and a control / arithmetic device.

  The antenna receives radiation noise and acquires a noise signal.

  The spectrum analyzer calculates the spectrum of a noise signal obtained by receiving radiation noise with an antenna.

  The receiver measures the noise level at the designated frequency point from the noise signal obtained by receiving the radiation noise with the antenna.

  The control / arithmetic apparatus controls the spectrum analyzer and the receiver and executes arithmetic processing.

Here, the control / arithmetic apparatus executes the following processing.
(5) The spectrum analyzer calculates the spectrum of each time domain of the noise in the frequency band of interest.
(6) An average spectrum of a plurality of spectra calculated by the spectrum analyzer is calculated.
(7) Based on the average spectrum, the frequency point of the maximum noise level of each of the plurality of divided frequency bands obtained by dividing the frequency band of interest into a plurality is extracted.
(8) The receiver is caused to measure the noise level at the frequency point of the extracted maximum noise level in each of the plurality of divided frequency bands.
(9) The maximum value among the noise levels of the plurality of divided frequency bands measured by the receiver is obtained, and the maximum value is set as the noise level of the target frequency band.
In addition, the noise measurement program of the present disclosure is a program that causes the control / arithmetic apparatus of the noise measurement apparatus including the antenna, the spectrum analyzer, the receiver, and the control / arithmetic apparatus to execute the following processing.
(10) The spectrum analyzer calculates the spectrum of each time domain of the noise in the frequency band of interest.
(11) An average spectrum of a plurality of spectra calculated by the spectrum analyzer is calculated.
(12) Based on the average spectrum, the frequency point of the maximum noise level of each of a plurality of divided frequency bands obtained by dividing the frequency band of interest into a plurality is extracted.
(13) The receiver is caused to measure the noise level at the frequency point of the extracted maximum noise level in each of the plurality of divided frequency bands.
(14) The maximum value of the noise levels of the plurality of divided frequency bands measured by the receiver is obtained, and the maximum value is set as the noise level of the target frequency band.

  Here, the antenna receives the radiation noise and acquires a noise signal.

  The spectrum analyzer calculates the spectrum of a noise signal obtained by receiving radiation noise with an antenna.

  The receiver measures the noise level at the designated frequency point from the noise signal obtained by receiving the radiation noise with the antenna.

  The control / arithmetic apparatus is an apparatus that executes a program for controlling the spectrum analyzer and the receiver and for arithmetic processing.

  According to the noise measurement method, the noise measurement device, and the noise measurement program of the present disclosure, the noise level of the radiation noise can be measured with high accuracy and in a short time.

It is a block diagram which shows the noise measuring device as one Embodiment. It is a block diagram which shows the outline | summary of the hardware constitutions of a control and arithmetic unit. It is the figure which showed the noise measurement program as a comparative example performed with the control and arithmetic unit of a noise measuring device. It is the first half part of the flowchart of the noise measurement program executed by the control / arithmetic apparatus of the noise measurement device of the present embodiment. It is the latter half part of the flowchart of the noise measurement program performed with the control and arithmetic unit of the noise measurement apparatus of this embodiment. It is a conceptual diagram of a memory area. It is a figure showing an example of a spectrum. It is the figure which showed an example of the average spectrum. It is explanatory drawing of the process in the case of satisfy | filling the comparison process of the maximum value and (average value + threshold value) and maximum value> = (average value + threshold value). It is explanatory drawing of the process in the case of satisfy | filling the comparison process of maximum value and (average value + threshold value) and maximum value <(average value + threshold value).

  Hereinafter, embodiments will be described.

  FIG. 1 is a block diagram showing a noise measuring device as one embodiment.

  The noise measuring apparatus 100 includes an antenna 10, a switcher 20, a spectrum analyzer 30, a receiver 40, and a control / arithmetic apparatus 50. The measuring object 1 is placed on the turntable 60 and is rotatable, and the antenna 10 is installed at a position away from the measuring object 1 by a specified distance (for example, 3.0 m) and can be moved up and down by a lifting platform 70. It has become.

  The antenna 10 receives radiation noise from the measurement object 1 and generates a noise signal representing the noise.

  The switcher 20 switches whether the noise signal obtained by the antenna 10 is transmitted toward the spectrum analyzer 30 or the receiver 40.

  The spectrum analyzer 30 calculates the spectrum of the noise signal obtained by the antenna 10.

  The receiver 40 measures a noise level of a designated frequency within a bandwidth of 0.12 MHz.

  The control / arithmetic apparatus 50 is configured by a computer, and controls each of the turntable 60, the lift 70, the switcher 20, the spectrum analyzer 30, and the receiver 40 by executing a noise measurement program. Further, the control / arithmetic apparatus 50 further receives the spectrum calculated by the spectrum analyzer 30 and the information of the noise level measured by the receiver 40 by executing the noise measurement program, and executes a calculation process for noise measurement. .

  FIG. 2 is a block diagram showing an outline of the hardware configuration of the control / arithmetic apparatus.

  Here, a CPU (Central Processing Unit) 511, a memory 512, an HDD (Hard Disc Drive) 513, a display 514, a timer 515, and a device interface 516 are shown. These elements 511 to 516 are connected to each other via a bus 510.

  The CPU 511 is a central processing unit that executes a program.

  The memory 512 is a memory in which a program is expanded for execution by the CPU 511. The memory 512 is also used as a work area for programs executed by the CPU 511.

  The HDD 513 is a nonvolatile mass storage device that stores various programs and data.

  The display 514 is a device that has a display screen (not shown) and displays an image according to an instruction from the CPU 511 on the display screen.

  The timer 515 is an element that measures time.

  Further, the device interface 516 is connected to and controls the switcher 20, the spectrum analyzer 30, the receiver 40, the turntable 60, and the lifting platform 70. The device interface 516 also receives information on the spectrum calculated by the spectrum analyzer 30 and the noise level measured by the receiver 40.

  Note that FIG. 2 is not a diagram showing all the components of the computer constituting the control / arithmetic apparatus 50, but a diagram showing only the main components centering on the components required in the following description. is there.

  Here, the description of the embodiment will be left, and a noise measurement process as a comparative example will be described.

  FIG. 3 is a diagram showing a noise measurement program as a comparative example executed by the control / arithmetic apparatus of the noise measurement device. As the hardware configuration of the noise measuring apparatus, those shown in FIGS. 1 and 2 are used as they are.

  Here, first, the output of the switch is connected to a spectrum analyzer (abbreviation of spectrum analyzer) (step S101). Then, the spectrum is calculated by setting the target frequency range whose noise level is to be measured by the spectrum analyzer so that the span width representing the width of the frequency range is set to about 100 MHz (step S102). Then, the spectrum calculated by the spectrum analyzer is acquired by the control / arithmetic unit 50 (step S103).

  And based on the acquired spectrum, some frequency points with a high noise level are extracted (step S104). These frequency points are approximate frequency points measured by the spectrum analyzer, and noise does not always exist at that frequency, meaning that there may be noise at frequencies near that frequency point. Yes. Therefore, paying attention to one of the extracted frequency points, a frequency 1 MHz lower than the focused frequency point is set in the receiver 40 (step S105). Then, the output of the switch 20 is connected to the receiver 40 (step S106). Thereafter, the receiver 40 is caused to measure the noise level while increasing the frequency of the receiver 40 by 0.1 MHz (step S107). Then, the measured noise level is read (step S108). This is repeated 20 times until the noise level is read for (frequency point of interest + 1 MHz) (step S109).

  Next, the maximum radiation frequency at which the noise level among the measurements repeated 20 times becomes the maximum value is set in the receiver 40 (step S110). Subsequently, an attitude capable of obtaining the maximum radiation noise is searched for while rotating the turntable 60 or raising the antenna 10 by the lifting platform 70 (steps S111 to S116). Then, the noise level data is read with the found posture (step S117).

  Next, it is determined whether or not the above processing has been completed for all the frequency points extracted in step S104 (step S118). When there is an unmeasured frequency point, the process returns to step S105 and the above processing is repeated for the unmeasured frequency point. When the above processing is completed for all the frequency points extracted in step S104, the process proceeds to step S119, and it is determined whether or not the noise level measurement has been completed for all frequency ranges for which the noise level is to be measured ( Step S119). When the frequency range in which the noise level is to be measured remains, the process returns to step S101, and the processing after step S101 is repeated for any of the remaining frequency ranges. When the noise level measurement is completed for all the frequency ranges for which the noise level is to be measured, the process of this flow ends.

  According to the processing flow of FIG. 3, the time required from step S105 to step S110, that is, the time required to identify an accurate frequency generating noise for one frequency point is 2 minutes or more.

  It takes a lot of time to extract about 10 frequency points for one frequency range (span width of about 100 MHz), measure the noise level for each, and execute it for the entire range of 30 MHz to 1 GHz. Become.

  Based on the above processing flow as a comparative example, the description returns to the description of this embodiment.

  4 and 5 are respectively a first half part and a second half part of a flowchart of a noise measurement program executed by the control / arithmetic apparatus of the noise measurement apparatus (see FIG. 1) of the present embodiment. The flowcharts shown in FIGS. 4 and 5 will be described with reference to FIG.

  Here, first, the output of the switch 20 is connected to the spectrum analyzer (step S201). The spectrum is calculated by setting the target frequency range for which the noise level is to be measured with a span width of about 100 MHz (step S202). Then, the spectrum calculated by the spectrum analyzer is acquired by the control / arithmetic unit 50 (step S203). The processing of steps S201 to S203 so far is the same as the processing of steps S101 to S103 of the comparative example shown in FIG.

  Next, a frequency range having a span width of about ± 1 MHz including one frequency point among the extracted frequency points is set (step S205), and the memory area (500, 20) is further set in the control / arithmetic unit 50. ) Is prepared (step S206).

  FIG. 6 is a conceptual diagram of the memory area.

  Here, a two-dimensional memory area of m = 1 to 500 (horizontal axis) and n = 0 to 20 (vertical axis) is shown. Here, '500' is the number of frequency points on the frequency axis of the spectrum calculated by the spectrum analyzer. Further, “20” means that the spectrum is calculated 20 times as described below. Furthermore, the column of n = 0 is a column for storing the average spectrum of the spectrum calculated 20 times.

  Returning to FIG. 4, the description will be continued.

  In step S207, n = 1 is initialized, and in step S208, timer 515 (see FIG. 2) is set to 0 msec, and the timer 515 starts timing.

Next, the spectrum is acquired by the spectrum analyzer for the frequency range of ± 1 MHz including one frequency point extracted in step S204 (step S209). Then, the spectrum is stored in the column C1 (see FIG. 6) where m = 1 to 500 and n = 1 (step S210). That is, here, a spectrum composed of 500 points is represented by (d _1,1 , d _2,1 ,..., D _500,1 ).

  Next, it waits for 100 msec to elapse (steps S211 and S212).

When 100 msec has elapsed, when n ≦ 20 (step S213), n is incremented by 1 (step S214), the process returns to step S208, the spectrum is acquired again, and this time, the column C2 of n = 2 (FIG. 6). Stored in the reference). The 500 points of the spectrum at this time are expressed as (d ₁ , ₂ , d ₂ , ₂ , d ₅₀₀ , ₂ ).

  The above steps S208 to S213 are repeated 20 times. Then, the spectrum calculated 20 times is stored in each column C1 to C20 of n = 1 to 20 shown in FIG.

  Next, 20 average values of the memory (m, n = 1 to 20) are taken and stored in the memory (m = 1 to 500, n = 0) (step S215).

That is, here
d _1,0 = (d _1,1 + d _1,2 +... + d _1,20 ) / 20
d _2,0 = (d _2,1 + d _2,2 + ... + d _2,20 ) / 20
:
_{d 500,0 = (d 500,1 + d} 500,2 + ... + d 500,20) / 20
(D _1,0 , d _2,0 ,..., D _500,0 ) is stored in the column C0 where n = 0.

  The above average value processing will be described again with reference to a diagram showing a spectrum.

  FIG. 7 is a diagram illustrating an example of a spectrum. Here, a spectrum obtained by calculating the vicinity of 126 MHz with a span width of ± 1 MHz is shown.

  FIG. 7A shows a spectrum at a certain moment, and FIG. 7B shows a spectrum at a point in time after 100 msec from that moment. FIG. 7C is a spectrum showing the maximum value of each point while holding the maximum value for each point for 500 seconds for each of 500 points (see FIG. 6). Although FIG. 7C is irrelevant to the flows shown in FIGS. 4 and 5, the spectrum is shown here for reference.

  These spectra include sudden noise n1 in addition to noise n0 that always appears. If such a spectrum including sudden noise is used as it is, the sudden noise may be misunderstood as a noise to be measured, and an erroneous result may be caused.

  FIG. 8 is a diagram showing an example of an average spectrum.

  The average spectrum shown in FIG. 8 is an average spectrum calculated from the spectrum of 20 times every 100 msec calculated in step S215 of FIG.

  In this average spectrum, sudden noise n1 as shown in FIG. 7 disappears, and only noise n0 that appears constantly appears.

  Returning to the flow of FIGS. 4 and 5, the description will be continued.

  When the average spectrum is calculated in step S215 shown in FIG. 4 and stored in the memory, in step S216, the frequency point at the maximum level in the average spectrum is extracted.

  Next, the output of the switcher 20 is switched to the receiver 40 (step S217 in FIG. 5), the maximum value MAX and average value AV of the average spectrum are calculated, and the maximum value MAX is equal to or greater than (average value AV + threshold TH). It is determined whether or not (step S218).

  FIG. 9 is an explanatory diagram of the comparison process between the maximum value and (average value + threshold) and the process when the maximum value ≧ (average value + threshold) is satisfied.

  Here, 6 dB is adopted as an example of the threshold value TH.

Here, the average value = AV refers to the column C0 of n = 0 in FIG.
AV = (d _1,0 + d _2,0 +... + D _500,0 ) / 500
(The value shown in FIG. 9 is about 22 dB), and the maximum value MAX is about 38 dB in the example shown in FIG.

  In the example shown in FIG. 9A, the maximum value ≧ (average value + threshold value). In this case, it is recognized that the noise is narrow band noise, and the process proceeds to step S222. Then, the frequency is set in the receiver 40 in order to measure the noise level of the frequency that has been searched for in step S216 (125.8 MHz indicated by a circle and an arrow in the example shown in FIG. 9).

  Thereafter, in the same manner as steps S111 to S117 in FIG. 3, a posture in which the maximum radiation noise can be obtained for the set frequency is searched while rotating the turntable 60 or raising the antenna 10 by the lift 70 (steps S223 to S228). ). Then, the noise level of the maximum radiation noise is read with the found posture (step S229).

  Next, as in the flow of FIG. 3, it is determined whether or not the above processing has been completed for all the frequency points extracted in step S204 (step S230). When there is an unmeasured frequency point, the process returns to step S205 and the above processing is repeated for the unmeasured frequency point. When the above process is completed for all the frequency points extracted in step S204, the process proceeds to step S231. Here, it is determined whether or not the measurement of the noise level is completed for all frequency ranges for which the noise level is to be measured. When the frequency range in which the noise level is to be measured remains, the process returns to step S201, and the processing after step S201 is repeated for any of the remaining frequency ranges. When the noise level measurement is completed for all the frequency ranges for which the noise level is to be measured, the processing shown in FIGS. 4 and 5 ends.

Next, in step S218,
Maximum value <average value + 6 dB
The case where it is determined that the above will be described.

  In this case, it is recognized as broadband noise, the frequency band is divided into a plurality (here, five as an example), and the maximum frequency of each divided band is extracted (step S219).

  FIG. 10 is an explanatory diagram of the comparison process between the maximum value and (average value + threshold) and the process when the maximum value <(average value + threshold) is satisfied.

  FIG. 10A shows the average spectrum of 20 times, the maximum value MAX, and the average value AV of the spectrum, as in the case of FIG. 9A. In the case of FIG. 9, one frequency (125.8 MHz in the case of FIG. 9) is an average spectrum having a shape that is specifically raised, but FIG. The raised shape is not seen. In the case of FIG. 10A, the maximum value MAX <average value AV + threshold (here 6 dB). In this case, it is recognized as broadband noise.

  FIG. 10B is an explanatory diagram of step S220 in FIG. Here, the frequency band of 126.0 MHz ± 1.0 MHz is divided into five. Then, frequency points (frequency points indicated by circles and arrows in FIG. 10B) at the maximum levels on the same average spectrum as in FIG. 10A in each of the divided bands divided into five are extracted. The

  When a plurality of (in this case, five) frequency points are extracted within the frequency band in this way, the five frequency points are set in the receiver 40 sequentially, one by one. Are sequentially measured (step S220). Then, the maximum value among the noise levels at these five frequency points (a total of five noise levels) is extracted (step S221).

  In step S222, the maximum frequency extracted in step S221 is set in the receiver 40, and the maximum emission noise at that frequency is read in the same manner as in the case of the narrow band noise described above (steps S223 to S228). (Step S229).

  For broadband noise, its frequency range (± 1 MHz frequency range in the example shown in FIGS. 4 and 5) is divided into a plurality (5 divisions in the example shown in FIGS. The maximum frequency is set and their noise levels are measured. In this way, the noise level of a plurality of frequencies is measured, and the frequency of the maximum noise level among them is detected as the frequency of noise generation in that frequency range (± 1 MHz band). In this way, the frequency point of noise generation is also extracted with high accuracy for broadband noise. For narrowband noise, it is also possible to extract the frequency point of noise generation in the same procedure as for broadband noise. However, in the case of narrowband noise, it is possible to immediately extract the noise frequency point as shown in FIG. 9B. For this reason, in the present embodiment, processing is divided into narrow band noise and broadband noise in order to shorten the time.

  In the case of narrow band noise, the processing time is about 2 seconds between Step S205 and Step S216, and about 1 second between Steps S217 and S222. That is, for narrowband noise, it takes about 3 seconds to perform the processing corresponding to steps S105 to S110 shown in the comparative example of FIG. In the case of broadband noise, steps S205 to S216 are about 2 seconds as in the narrow band, and it takes about 30 seconds from step S218 through step S219 to step S222. That is, even in the case of broadband noise, the time required to perform the processing corresponding to “2 minutes or more” shown in the comparative example of FIG. 3 is about 32 seconds.

  In the case of broadband noise, it takes more time than in the case of narrow band noise, but in either case, the time is significantly reduced compared to the comparative example shown in FIG.

  In this example, the processing is divided into broadband noise and narrowband noise. However, as described above, the broadband noise processing is executed without distinguishing between broadband noise and narrowband noise. May be. In that case, when the result is narrow band noise, it takes time unnecessarily, but still a significant time reduction can be realized as compared with the comparative example shown in FIG.

DESCRIPTION OF SYMBOLS 1 Measurement object 10 Antenna 20 Switching device 30 Spectrum analyzer 40 Receiver 50 Control / arithmetic device 60 Turntable 70 Lifting table 100 Noise measuring device 510 Bus 511 CPU
512 memory 513 HDD
514 Display 515 Timer 516 Device interface

Claims (12)

Calculate the spectrum of each time domain of noise in the frequency band of interest and calculate the average spectrum of the frequency band of interest,
Based on the average spectrum, the frequency point of the maximum noise level of each of a plurality of divided frequency bands obtained by dividing the frequency band of interest into a plurality of parts is extracted,
Measure the noise level at the frequency point of the extracted maximum noise level for each of the plurality of divided frequency bands,
A noise measurement method, wherein a maximum value among a plurality of measured noise levels of the plurality of divided frequency bands is set as a noise level of the target frequency band. Based on the average spectrum, the frequency band of interest is divided into either a broadband in which noise is distributed in a relatively wide frequency band or a narrow band in which noise is concentrated in a relatively narrow frequency band,
2. When the target frequency band is allocated to broadband, each process after extraction of frequency points of each of a plurality of divided frequency bands obtained by dividing the target frequency band into a plurality of parts is executed. The noise measurement method described. Calculate the maximum level and average level of the average spectrum,
Comparing the maximum level with the average level;
When the maximum level is equal to or greater than a value obtained by adding a predetermined threshold to the average level, the frequency band of interest is allocated to a narrow band, and the maximum level is less than a value obtained by adding the threshold to the average level. The noise measurement method according to claim 2, wherein the frequency band of interest is allocated to broadband.   The noise level of the frequency point of the maximum noise level of the average spectrum is measured when the frequency band of interest is allocated to the narrow band, and the noise level is set as the noise level of the frequency band of interest. The noise measuring method according to 2 or 3. An antenna that receives radiated noise and obtains a noise signal;
A spectrum analyzer for calculating a spectrum of a noise signal obtained by receiving radiation noise with the antenna;
A receiver that measures a noise level at a specified frequency point from a noise signal obtained by receiving radiation noise with the antenna;
A control / arithmetic unit that controls the spectrum analyzer and the receiver and executes arithmetic processing,
The control / arithmetic unit is
Let the spectrum analyzer calculate the spectrum of each time domain of noise in the frequency band of interest,
Calculate an average spectrum of a plurality of spectra calculated by the spectrum analyzer,
Based on the average spectrum, the frequency point of the maximum noise level of each of a plurality of divided frequency bands obtained by dividing the frequency band of interest into a plurality of parts is extracted,
Let the receiver measure the noise level at the frequency point of the extracted maximum noise level for each of the plurality of divided frequency bands,
A noise measuring apparatus characterized in that a maximum value among the noise levels of the plurality of divided frequency bands measured by the receiver is obtained and the maximum value is set as a noise level of the frequency band of interest. The control / arithmetic unit is
Based on the average spectrum, the frequency band of interest is divided into either a broadband in which noise is distributed in a relatively wide frequency band or a narrow band in which noise is concentrated in a relatively narrow frequency band,
6. The processing after extraction of frequency points of each of a plurality of divided frequency bands obtained by dividing the target frequency band into a plurality of parts when the target frequency band is distributed to broadband. Noise measurement equipment. The control / arithmetic unit is
Calculate the maximum level and average level of the average spectrum,
Comparing the maximum level with the average level;
When the maximum level is equal to or greater than a value obtained by adding a predetermined threshold to the average level, the frequency band of interest is allocated to a narrow band, and the maximum level is less than a value obtained by adding the threshold to the average level. 7. The noise measuring apparatus according to claim 6, wherein the frequency band of interest is allocated to broadband.   The control / arithmetic unit causes the receiver to measure the noise level at the frequency point of the maximum noise level of the average spectrum and distribute the noise level to the noise of the frequency band of interest when the frequency band of interest is allocated to the narrow band. 8. The noise measuring device according to claim 6, wherein the noise measuring device is a level. An antenna that receives radiated noise and obtains a noise signal;
A spectrum analyzer for calculating a spectrum of a noise signal obtained by receiving radiation noise with the antenna;
A receiver that measures a noise level at a specified frequency point from a noise signal obtained by receiving radiation noise with the antenna;
For the control / arithmetic apparatus of the noise measuring apparatus having a control / arithmetic apparatus for executing a program for controlling the spectrum analyzer and the receiver and for arithmetic processing,
Let the spectrum analyzer calculate the spectrum of each time domain of noise in the frequency band of interest,
Calculate an average spectrum of a plurality of spectra calculated by the spectrum analyzer,
Based on the average spectrum, the frequency point of the maximum noise level of each of a plurality of divided frequency bands obtained by dividing the frequency band of interest into a plurality of parts is extracted,
Let the receiver measure the noise level at the frequency point of the extracted maximum noise level for each of the plurality of divided frequency bands,
A noise measurement program, comprising: obtaining a maximum value among the noise levels of the plurality of divided frequency bands measured by the receiver, and executing a process of setting the maximum value as a noise level of the target frequency band. In addition to the control / arithmetic unit,
Based on the average spectrum, the frequency band of interest is divided into either a broadband in which noise is distributed in a relatively wide frequency band or a narrow band in which noise is concentrated in a relatively narrow frequency band,
10. The processing after extraction of frequency points of each of a plurality of divided frequency bands obtained by dividing the target frequency band into a plurality of parts when the target frequency band is distributed to broadband. Noise measurement program. In addition to the control / arithmetic unit,
Calculate the maximum level and average level of the average spectrum,
Comparing the maximum level with the average level;
When the maximum level is equal to or greater than a value obtained by adding a predetermined threshold to the average level, the frequency band of interest is allocated to a narrow band, and the maximum level is less than a value obtained by adding the threshold to the average level. The noise measurement program according to claim 10, further comprising: processing to distribute the target frequency band to broadband.   When the control / arithmetic unit distributes the target frequency band to a narrow band, the receiver measures the noise level at the frequency point of the maximum noise level of the average spectrum and determines the noise level as noise in the target frequency band. The noise measurement program according to claim 10 or 11, wherein a process for setting a level is executed.

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