JP7206639B2 - System for Identifying Vulnerable Areas of Noise Immunity in Circuit Boards and Method for Identifying Vulnerable Areas of Noise Immunity - Google Patents

Description

TECHNICAL FIELD The present invention relates to a noise-tolerant weak point identifying system and a noise-tolerant weak point identifying method for identifying a weak noise-tolerant point on a circuit board.

Conventionally, systems and methods of this type for identifying weak noise-resistant locations on a circuit board include, for example, a malfunction location identification method and a malfunction location identification system disclosed in Patent Document 1.

In this malfunction location identification method and system, the probe is scanned by the position controller to apply radiated noise from the probe to a plurality of preset points on the circuit board and to inject the second conduction noise into the circuit board. . The personal computer acquires the output signal of the gyro sensor on the circuit board as a CAN signal through the microcomputer and determines whether or not there is a malfunction. The determination of the presence or absence of malfunction is made by determining whether or not the CAN signal exceeds a predetermined threshold. Points exceeding the value are identified as malfunction locations.

Japanese Unexamined Patent Application Publication No. 2014-21013

However, in the conventional method and system for identifying a malfunction location disclosed in Patent Document 1, it is possible to identify a malfunction location by determining whether or not a malfunction actually occurred in a circuit board, but the malfunction actually occurred. It is not possible to monitor the condition of the circuit board before it occurs. Moreover, in order to determine whether or not there is a malfunction, it is necessary to give the output signal of the gyro sensor to the microcomputer and obtain the CAN signal. Therefore, the output signal of the gyro sensor is required as a control signal for the microcomputer to identify the malfunctioning location, and the presence of the gyro sensor and the microcomputer is required.

The present invention was made to solve such problems,
A noise source that generates noise, a noise application means that sequentially applies noise to a plurality of locations on a circuit board, and a propagation noise transmitted from the noise application locations on the circuit board are measured at a noise measurement location on the circuit board. a measuring device, a comparing device for comparing the noise level of the propagated noise measured by the measuring device at the noise measurement point with the permissible level of the propagated noise allowed at the noise measuring point, and obtained by the comparing device for a plurality of points on the circuit board. and an analysis device that identifies a weak point of noise immunity in a circuit board based on a plurality of comparison results obtained, and configures a system for identifying a weak point in noise immunity in a circuit board.

Further, the present invention comprises a first step of sequentially applying noise generated by a noise source to a plurality of locations on a circuit board by a noise applying means; and a third step of comparing the noise level of the propagation noise measured by the measurement device at the noise measurement location with the permissible level of propagation noise allowed at the noise measurement location. and a fourth step of identifying a location of weak noise immunity on a circuit board based on a plurality of comparison results obtained for a plurality of locations on the circuit board.

According to the present invention, it is possible to monitor the state of a circuit board before a malfunction occurs, and to easily identify a weak point of noise immunity in the circuit board with a simple configuration. A vulnerable point identification system and a noise tolerant vulnerable point identification method can be provided.

1 is a diagram showing a schematic configuration of a system for identifying a noise-tolerant weak point in a circuit board according to a first embodiment of the present invention; FIG. 4 is a flow chart showing a method for specifying a noise immunity weak point in a circuit board according to the first embodiment of the present invention; 4 is a graph showing the frequency spectrum of each signal measured at a predetermined location on the circuit board by the measuring device that constitutes the system for identifying weak noise immunity locations on the circuit board according to the first embodiment; FIG. 10 is a diagram showing a schematic configuration of a system for specifying a noise-resistant weak point in a circuit board according to a modification of the first embodiment of the present invention; FIG. 10 is a diagram showing a schematic configuration of a system for identifying a noise-resistant weak point in a circuit board according to a second embodiment of the present invention; FIG. 11 is a diagram showing a schematic configuration of a system for specifying a noise-resistant weak point in a circuit board according to a third embodiment of the present invention;

Next, a description will be given of a form for implementing the system for specifying a weak point in noise immunity and the method for specifying a weak point in noise immunity in a circuit board according to the present invention.

FIG. 1 is a diagram showing a schematic configuration of a system 1 for identifying a noise-tolerant weak point in a circuit board according to the first embodiment of the present invention.

In order to identify a noise-resistant weak point on a circuit board 2, the noise-resistant weak point identifying system 1 includes a function generator (hereinafter referred to as FG) 3 as a noise source that generates noise. The FG 3 generates as noise a GSM signal of a communication system conforming to a predetermined digital communication standard used for digital mobile phone calls, which is the GSM (Global System for Mobile Communication (registered trademark)) standard in this embodiment. The GSM signal generated by FG3 is applied to probe 4 .

Probe 4 provides an incoming GSM signal to circuit board 2 either by radiation or conduction. The probe 4 is mechanically scanned three-dimensionally with respect to the circuit board 2 by the probe scanning device 5 , and applies noise to a plurality of predetermined locations on the entire surface of the circuit board 2 . The probe scanning device 5 has sliders in the x-axis, y-axis, and z-axis directions, and moves the probe 4 in the three-axis directions according to control signals from a personal computer (PC) 6 . to drive. The probe 4 and probe scanning device 5 constitute noise applying means for applying GSM signals as noise to a plurality of locations on the circuit board 2 . For example, when a GSM signal is given from the probe 4 to the circuit board 2 by radiation, a space is provided between the tip of the probe 4 and the circuit board 2, and the GSM signal is given from the probe 4 to the circuit board 2 by conduction. The tip of the probe 4 is brought into contact with the circuit board 2 when the probe 4 is connected.

A plurality of electronic components (not shown) are mounted on the circuit board 2 and connected by wiring patterns (not shown). A speaker 8 is connected to the illustrated electronic component 7 via a pair of signal lines 9 . The speaker 8 outputs sound according to the audio signal propagating through the pair of signal lines 9 . A spectrum analyzer (hereinafter referred to as SPA) 11 is connected to the signal line 9 via an amplifier (hereinafter referred to as AMP) 10 . The SPA 11 constitutes a measuring device for measuring noise applied to the circuit board 2 by the probe 4 and transmitted to a predetermined portion of the circuit board 2, which in this embodiment is a signal line 9 for outputting an audio signal. PC6 is connected to SPA11, and SPA11 outputs the measured noise to PC6.

The PC 6 has a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). According to the computer program stored in the ROM, the RAM is used as a temporary storage work area, and the CPU executes predetermined processing. . In this embodiment, the CPU, ROM and RAM provided in the PC 6 constitute a comparison device and an analysis device. The comparator compares the noise level of noise measured by the SPA 11 with the allowable level of noise allowed on the signal line 9 by processing executed by the CPU according to a computer program stored in the ROM. The analysis device identifies locations of weak noise immunity on the circuit board 2 based on a plurality of comparison results obtained by the comparison device for a plurality of locations on the circuit board 2 through processing executed by the CPU according to a computer program stored in the ROM. Identify.

Specifically, when the comparison result that the noise level of the noise measured by the SPA 11 is equal to or less than the allowable level is obtained in the comparison device for all of the plurality of locations, the analysis device detects the noise at the level closest to the allowable level. The point where is measured is identified as the weakest point in terms of noise immunity. In addition, if the comparison device obtains a comparison result in which the noise level measured by the SPA 11 exceeds the allowable level for any of a plurality of locations, the analysis device measures the noise at a level that most exceeds the allowable level. The point is identified as the weakest point of noise immunity.

The comparison device and the analysis device are configured by computer program software in the PC 6 in this embodiment, but are not limited to this. For example, an electronic circuit that performs similar functions may be formed and configured by hardware.

FIG. 2 is a flow chart showing a method for specifying a noise immunity weak point in a circuit board according to the first embodiment of the present invention, which is performed by a computer program in the PC 6. As shown in FIG.

In this method for specifying a weak noise resistance location, first, in a first step S1, the GSM signal generated by the FG3 is applied as noise to a plurality of locations on the circuit board 2 by the noise application means. At this time, under the control of the PC 6, the probe 4 is automatically scanned in three axial directions by the probe scanning device 5, and the GSM signals are given from the probe 4 to a plurality of predetermined locations on the entire circuit board 2, so that the circuit The entire substrate 2 is evaluated for noise immunity. Next, in a second step S2, the SPA 11 measures noise transmitted to the signal line 9 of the circuit board 2. FIG. Next, in a third step S3, the noise level of the noise measured by the SPA 11 is compared with the permissible level of noise permissible on the signal line 9 by means of a comparator. Next, in a fourth step S<b>4 , locations of weak noise resistance on the circuit board 2 are identified based on a plurality of comparison results obtained by a comparison device for a plurality of locations on the circuit board 2 .

In the present embodiment, in the fourth step S4, if the comparison result that the noise level of the noise measured by the SPA 11 is equal to or less than the allowable level is obtained in the comparison device for all of the plurality of locations, and if the noise level exceeds the allowable level If the comparison device obtains a comparison result that exceeds the threshold for any one of the plurality of locations, the analysis device identifies the weakest location in terms of noise immunity as described above.

In the present embodiment, in the fourth step S4, if the comparison device obtains the comparison result that the noise level of the noise measured by the SPA 11 is below the allowable level for all of the plurality of locations, the analyzer determines the allowable level The point where the noise level closest to is measured is identified as the weakest point of noise immunity. In addition, when the noise level measured by the SPA 11 exceeds the allowable level at any one of a plurality of locations, if the comparison device obtains a comparison result, the analysis device measures the noise at the level that most exceeds the allowable level. A point is identified as the weakest point of noise immunity.

According to the system 1 for identifying a weak point in noise immunity and the method for identifying a weak point in noise immunity in the circuit board 2 according to the present embodiment, the GSM signal is applied as noise to a plurality of places on the circuit board 2, and the signal line of the circuit board 2 is 9 is measured by the SPA 11, and the results of comparison between the measured noise level and the allowable noise level allowed in the signal line 9 are obtained for a plurality of locations on the circuit board 2. It is possible to grasp to what extent each GSM signal applied to a point affects the noise immunity of the signal line 9 of the circuit board 2 .

Therefore, it becomes possible to monitor the state of the circuit board 2 before malfunction occurs, which has not been possible conventionally. In addition, since there is no need to check the presence or absence of a malfunction as in the conventional malfunction location identification method and malfunction location identification system, there is no need to monitor the CAN signal obtained by giving the output signal of the gyro sensor to the microcomputer. This eliminates the need for a gyro sensor or a microcomputer, and makes it possible to easily identify a portion of the circuit board 2 with weak noise immunity with a simple configuration.

Further, according to the system 1 for specifying a weak point in noise immunity and the method for specifying a weak point in noise immunity in a circuit board according to the present embodiment, the weak point in the noise immunity in the circuit board 2 can be specified. In addition, it is possible to grasp whether or not the noise resistance of the vulnerable portion is within the allowable level. In addition, it is possible to quantitatively grasp how weak the noise resistance of the vulnerable portion is from the level difference between the measured noise level and the allowable level.

Further, according to the system 1 for identifying a weak point in noise immunity and the method for identifying a weak point in noise immunity in a circuit board according to the present embodiment, the GSM signal used for communication of a digital mobile phone is applied to the signal line for outputting the audio signal of the circuit board 2. 9 as noise. In addition, by measuring the noise transmitted to the signal line 9 for outputting the audio signal of the circuit board 2 by the SPA 11, it is possible to grasp which frequency band the GSM signal used for communication of the digital mobile phone affects as noise. be able to.

FIG. 3 shows a graph of the frequency spectrum of the signal on the signal line 9 measured by the SPA 11, the horizontal axis of each graph shown in (a) and (b) of the same figure is the signal frequency (frequency) [HZ], The vertical axis is the electric field (Field Strength) [dBμV] representing the signal strength. The signal frequency on the horizontal axis is in the range of 20 [HZ] to 20 k [HZ] where speech is recognized.

FIG. 1(a) is a graph showing the frequency spectrum of each signal on the signal line 9 when a GSM signal is applied to a specific portion of the circuit board 2 and when the GSM signal is not applied, in comparison with the allowable noise level on the signal line 9. is. In the graph, the frequency spectrum 21 of the black signal is the frequency spectrum when the GSM signal is applied to a specific portion of the circuit board 2 (there is a GSM signal), and the frequency spectrum 22 of the gray signal is the frequency spectrum when the GSM signal is applied to the circuit board 2. Frequency spectrum without (no GSM signal), the gray line 23 is the permissible noise level (limit) on the signal line 9 .

From the graph, when a GSM signal is applied to a specific portion of the circuit board 2, the frequency spectrum 22 of the signal with low signal strength becomes the frequency spectrum 21 of the signal with high signal strength, and noise is added to the signal line 9. understood. Moreover, the intensity of the frequency spectrum 21 of the signal on the signal line 9 exceeds the limit value in the frequency range of about 4.5 k[HZ] or less, and an abnormal sound (sound noise) is heard from the speaker 8 . In this frequency range, the noise level that causes sound noise can be quantitatively grasped for each frequency from the intensity of the frequency spectrum 21 of the signal exceeding the limit value. Also, the margin of noise resistance in the signal line 9 can be grasped for each frequency from the level difference between the intensity of the frequency spectrum 21 of the signal in the frequency range exceeding about 4.5 k[HZ] and the limit value.

FIG. 2(b) shows a case where a GSM signal is applied to a specific portion of the circuit board 2 without applying noise countermeasures to the circuit board 2, and a case where a GSM signal is applied to a specific portion of the circuit board 2 after applying noise countermeasures to the circuit board 2. 4 is a graph showing the frequency spectrum of each signal on the signal line 9 in comparison with the allowable noise level in the signal line 9 when the GSM signal is given. Noise countermeasures were taken for the most vulnerable locations identified by the system 1 for identifying vulnerable locations in noise immunity and the method for identifying vulnerable locations in noise immunity in the circuit board according to this embodiment. In the same graph, the frequency spectrum 24 of the black signal is the frequency spectrum when the GSM signal is applied to the circuit board 2 without noise countermeasures (with GSM signal). is the same as the frequency spectrum 21 of the signal of . Further, the frequency spectrum 25 of the gray signal is the frequency spectrum when the circuit board 2 is subjected to noise countermeasures and then the GSM signal is given to a specific portion of the circuit board 2 (with countermeasures), and the gray line 23 is the signal line 9. is the allowable noise level (limit value) in

From the same graph, it can be seen that by performing noise countermeasures on the most vulnerable locations identified by the system 1 for identifying vulnerable locations of noise immunity and the method for identifying vulnerable locations of noise immunity in the circuit board according to the present embodiment, a signal indicating that countermeasures are taken is given. It is understood that the intensity of the frequency spectrum 25 of the signal on the signal line 9 is suppressed below the limit value in the frequency range of about 4.5 k[HZ] or less. Therefore, the effect of noise countermeasures can be confirmed, and the effect of the countermeasures can be quantitatively measured.

Further, according to the system 1 for specifying a weak point in noise immunity and the method for specifying a weak point in noise immunity in a circuit board according to the present embodiment, the three-dimensional position of the probe 4 is mechanically scanned by the probe scanning device 5, and the position of the circuit board 2 is A GSM signal is applied from the probe 4 to a plurality of predetermined locations on the entire surface. As a result, the trouble of manually scanning the probe 4 can be saved, and the work of identifying weak points in noise resistance is facilitated.

In addition, in the system 1 for identifying a noise resistant weak point in a circuit board according to the first embodiment, the probe 4 is automatically scanned in three axial directions by the probe scanning device 5 under the control of the PC 6, and the probe 4 to the circuit board 2 GSM signals were applied at predetermined locations throughout. However, the probe 4 can be moved within a limited range, and the configuration may be such that the GSM signal is applied to arbitrary multiple locations in the limited area of the circuit board 2 .

FIG. 4 shows a schematic configuration of a system 1A for identifying a noise-tolerant weak point in a circuit board according to a modification of the first embodiment. 4 and a probe position varying device 41 . In the figure, the same reference numerals are given to the same or corresponding parts as in FIG. 1, and the description thereof will be omitted. The probe position varying device 41 is composed of a slider capable of moving the probe 4 within a limited range in the x-axis direction, y-axis direction and z-axis direction. The probe position varying device 41 arbitrarily varies the three-dimensional position of the probe 4 with respect to the circuit board 2 according to an operation signal input from the keyboard of the PC 6, and moves the probe 4 to arbitrary plural locations in a limited area of the circuit board 2. Apply a GSM signal.

A circuit board noise immunity weak point identification system 1A according to a modification of the first embodiment is the same as the noise immunity weak point identification system 1 on a circuit board according to the first embodiment except for the above points. In addition, in the method of specifying a noise-resistant weak point using the system 1A for specifying a noise-resistant weak point in a circuit board according to the modification of the first embodiment, the keyboard of the PC 6 is operated in the first step S1 of the flow chart shown in FIG. The only difference from the noise immunity weak point identification method according to the first embodiment described above is that the GSM signal is applied to a limited area of the circuit board 2 .

According to the system 1A for identifying a vulnerable location of noise immunity in a circuit board and the method for identifying a vulnerable location of noise immunity in a circuit board according to the modified example of the first embodiment, when the noise tolerance evaluation target area in the circuit board 2 is limited, By arbitrarily varying the three-dimensional position of the probe 4 with respect to the circuit board 2 in a limited area of the circuit board 2 by the probe position varying device 41, the GSM signal from the probe 4 is applied as noise to a plurality of arbitrary locations on the circuit board 2. can be applied. Therefore, by arbitrarily selecting a portion of the circuit board 2 that is susceptible to noise, for example, the signal line 42 on the circuit board 2 and applying the GSM signal to the signal line 42 from the probe 4, the noise immunity is weakened. Location can be specified with high accuracy.

In the first embodiment, noise is applied to a plurality of predetermined locations on the circuit board 2, and in the above modification, noise is applied to a plurality of arbitrary locations in a limited area of the circuit board 2. At least a limited region of the substrate 2 or the entire substrate surface may be scanned comprehensively to apply noise comprehensively to at least the limited region of the circuit board 2 or the entire substrate surface.

FIG. 5 is a diagram showing a schematic configuration of a system 1B for identifying a noise resistant weak point in a circuit board according to a second embodiment of the present invention. In the figure, the same reference numerals are given to the same or corresponding parts as in FIG. 1, and the description thereof will be omitted.

In the system 1 for specifying a weak point in noise immunity in a circuit board according to the first embodiment, the noise applying means is composed of the probe 4 and the probe scanning device 5, but the system for specifying a weak point in noise immunity in the circuit board according to the second embodiment In 1B, the noise application means is composed of an array antenna 31 and antenna selection means. The PC 6 does not control the position of the probe 4 by controlling the probe scanning device 5 as in the first embodiment, but controls the opening and closing of the switch 32 constituting the antenna selection means.

The array antenna 31 is configured by arranging a plurality of antennas 31a in the x-direction and the y-direction so as to face the back surface of the circuit board 2 in the area to be evaluated for noise immunity. In this embodiment, the entire surface of the circuit board 2 is evaluated for noise immunity. An array antenna 31 is installed at the end. Each of the plurality of antennas 31a is provided with a plurality of switches 32, like the array antenna 31 partially enlarged in FIG. The opening and closing of each switch 32 is controlled by the PC 6, and among the plurality of antennas 31a constituting the array antenna 31, the antenna 31a that radiates the GSM signal output from the FG3 is turned on. selected. By selecting the switch 32 by the PC 6 , the GSM signal is applied to each of predetermined multiple locations on the entire surface of the circuit board 2 .

A noise immunity weak point identification system 1B in a circuit board according to the second embodiment is the same as the noise immunity vulnerable point identification system 1 in a circuit board according to the first embodiment except for the above points. In addition, in the method for identifying a noise-resistant weak point using the system 1B for identifying a noise-resistant weak point in a circuit board according to the second embodiment, each switch 32 is opened and closed by the PC 6 in the first step S1 of the flow chart shown in FIG. By being controlled, the antenna 31a that radiates the GSM signal is selected from among the plurality of antennas 31a forming the array antenna 31, and the GSM signal is applied to the circuit board 2. It is different from the method of specifying a noise immunity weak point according to the embodiment.

According to the system 1B for identifying a weak point in noise immunity and the method for identifying a weak point in a noise immunity in a circuit board according to the second embodiment, the antenna 31a for radiating a GSM signal out of the plurality of antennas 31a constituting the array antenna 31 is selected by the switch 32 , the GSM signal can be radiated from the array antenna 31 to a plurality of locations on the circuit board 2 . Therefore, since the GSM signal can be applied to a plurality of locations on the circuit board 2, the time required to measure the noise transmitted from the plurality of locations on the circuit board 2 to the signal line 9 of the circuit board 2 can be shortened, and the location of weak noise resistance can be identified. Work can be done quickly.

FIG. 6 is a diagram showing a schematic configuration of a system 1C for identifying a noise resistant weak point in a circuit board according to a third embodiment of the present invention. In the figure, the same reference numerals are given to the same or corresponding parts as in FIG. 1, and the description thereof will be omitted.

A system 1C for specifying a noise resistant weak point in a circuit board according to the third embodiment includes a probe 4 for manually applying a GSM signal as noise to an arbitrary point of a circuit board 2 as noise applying means.

A noise immunity weak point identification system 1C in a circuit board according to the third embodiment is the same as the noise immunity vulnerable point identification system 1 in a circuit board according to the first embodiment except for the above points. In addition, in the method of specifying a noise-resistant weak point using the system 1C for specifying a noise-resistant weak point in a circuit board according to the third embodiment, the first step S1 of the flow chart shown in FIG. The GSM signal is manually applied from the probe 4 to .

According to the system 1C for identifying a weak point in noise immunity in a circuit board and the method for identifying a weak point in a noise immunity in a circuit board according to the third embodiment, when the noise immunity evaluation target area in the circuit board 2 is limited, the probe 4 By manually moving the three-dimensional position with respect to the circuit board 2 , the GSM signal can be applied as noise from the probe 4 to arbitrary multiple locations on the circuit board 2 . For this reason, in the third embodiment as well, similarly to the system 1A for identifying a noise-tolerant vulnerable location on a circuit board according to the modification of the first embodiment, a location susceptible to noise on the circuit substrate 2, for example, a circuit substrate By arbitrarily selecting the signal line 42 in 2 and applying the GSM signal from the probe 4 to the signal line 42, it is possible to identify the weak point of the noise resistance with high accuracy.

In each of the above-described embodiments and modifications, the case where the predetermined portion of the circuit board 2 where noise is measured by the SPA 11 is the signal line 9 for outputting the audio signal has been described. However, the predetermined location of the circuit board 2 where the noise is measured is not limited to this. It's okay. In addition, in each of the above-described embodiments and modifications, the GSM standard is used as an example of the predetermined digital communication standard used for digital mobile phone calls, but the communication system is not necessarily limited to this. Other communication methods may be used. Other communication systems include, for example, cellular systems (GSM (registered trademark), WCDMA (registered trademark), LTE, etc.) and short-range wireless communication (Wi-Fi (registered trademark), Bluetooth (registered trademark), etc.). mentioned. Also, noise is not limited to signals conforming to a predetermined digital communication standard used for digital mobile phone calls. Further, in each of the above-described embodiments and modifications, the case where the noise source is configured by the FG3 has been described, but the mobile phone itself may be used as the noise source. Further, in each of the above embodiments and modifications, the case where the measuring device for measuring noise is the SPA 11 that measures signals along the frequency axis has been described. There may be.

DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C... Noise-resistant weak point identification system 2... Circuit board 3... Function generator (FG: noise source)
4... Probe 5... Probe scanning device 6... Personal computer (PC: comparison device/analysis device)
7... Electronic component 8... Speaker 9... Signal line (predetermined location)
10... Amplifier (AMP)
11... Spectrum analyzer (SPA: measuring device)
31... Antenna array 31a... Antenna 32... Switch (antenna selection means)
41 ... Probe position variable device

Claims (10)

a noise source that generates noise; a noise applying means that sequentially applies the noise to a plurality of locations on a circuit board; a measuring device for measuring in; a comparing device for comparing a noise level of the propagation noise measured by the measuring device at the noise measurement location with an allowable level of the propagation noise allowed at the noise measurement location; A system for identifying a weak noise-resistant area in a circuit board, comprising: an analysis device that identifies a weak noise-resistant area in the circuit board based on a plurality of comparison results obtained by the comparing apparatus for a plurality of locations on the circuit board. When the noise level of the propagation noise at the noise measurement location is equal to or lower than the allowable level, the analysis device determines the level closest to the allowable level when the comparison results are obtained for all of the plurality of noise application locations. When the noise application point when the propagation noise is measured and the noise level of the propagation noise at the noise measurement point exceeds the allowable level when the comparison result is obtained for any of the plurality of noise application points 2. The noise resistance weak point identification according to claim 1, wherein the noise application point when the level of the propagation noise that greatly exceeds the allowable level is measured is identified as the weak point in noise resistance. system. The noise generated by the noise source is a signal conforming to a predetermined digital communication standard used as a communication standard for digital mobile phone calls, and the noise measurement point is a signal line that outputs an audio signal. 3. A system for identifying noise-immune weak points according to claim 1, wherein said measuring device is a spectrum analyzer. The noise applying means includes a probe that applies the noise to the circuit board, and a plurality of predetermined locations on the entire surface of the circuit board by mechanically scanning the three-dimensional position of the probe with respect to the circuit board. 4. The system for specifying noise-tolerant weak points according to any one of claims 1 to 3, further comprising a probe scanning device that applies . The noise application means includes an array antenna that radiates the noise facing the circuit board in the area to be evaluated for noise resistance, and an antenna that radiates the noise from among a plurality of antennas constituting the array antenna. 4. The system for specifying a noise-resistant weak point according to claim 1, further comprising: antenna selection means for selecting a . The noise applying means includes a probe that applies the noise to the circuit board, and a three-dimensional position of the probe with respect to the circuit board that is arbitrarily varied to apply the noise to any plurality of locations in a limited area of the circuit board. 4. The system for specifying noise-resistant weak points according to any one of claims 1 to 3, further comprising a probe position varying device for applying voltage. 4. The noise applying means according to any one of claims 1 to 3, wherein the noise applying means comprises a probe that applies the noise to an arbitrary portion of the circuit board and is manually moved. The noise immunity vulnerability identification system described in . a first step of sequentially applying noise generated by a noise source to a plurality of locations on a circuit board by a noise applying means ; and comparing the noise level of the propagation noise measured by the measurement device at the noise measurement location with a permissible level of the propagation noise allowed at the noise measurement location. 3. A method for identifying a weak noise immunity location on a circuit board, comprising: 3 steps; and a fourth step of identifying a noise immunity weak location on the circuit board based on a plurality of comparison results obtained for a plurality of locations on the circuit board. In the fourth step, when the noise level of the propagation noise at the noise measurement location is equal to or lower than the allowable level, the level closest to the allowable level when the comparison results are obtained for all of the plurality of noise application locations. When the noise application point when the propagation noise is measured, and the comparison result that the noise level of the propagation noise at the noise measurement point exceeds the allowable level is obtained for any of the plurality of noise application points 9. The noise immunity weak point according to claim 8, wherein the noise application point when the level of the propagation noise that greatly exceeds the allowable level is measured is specified as the weak point of the noise immunity that is the weakest. specific method. In the first step, a signal conforming to a predetermined digital communication standard used as a communication standard for a digital mobile phone call is applied as the noise to a plurality of locations on the circuit board;
10. The method of specifying a noise immunity weak point according to claim 8, wherein, in said second step, said propagation noise transmitted to a signal line for outputting an audio signal of said circuit board is measured by a spectrum analyzer.

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