JPH05312867A - Noise finder device - Google Patents

Abstract

PURPOSE:To provide a device capable of promptly specifying noise generating parts on a mounting substrate. CONSTITUTION:A noise finder device is formed of a noise scanning part S, an image processing part G, a high frequency signal processing part K, and a data processing part D. The noise scanning part S is provided with a base mounting face 1. A moving shaft 7 movable in an X-axis direction and a Y-axis direction is provided below the base mounting face 1, and a micro-probe 2 is mounted to one place of the moving shaft 7, in proximity to the base mounting face 1. In the image processing part G, noise data in a plane position obtained by scanning operation is inputted into a personal computer C, and the distributed state and intensity of noise generated from mounted parts are displayed simultaneously in the overlapped state on the mounting substrate image plane of an output device. The automatic contraction control of the most intense noise generating source is performed in the high frequency signal processing part K and data processing part D. Since the intensity and distributed state of noise can be displayed simultaneously one over the other in details on the mounting substrate image plane, noise generating parts can be specified correctly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for automatically specifying the position of noise (electromagnetic waves) radiated from a printed wiring board on which an electronic circuit is mounted.

[0002]

2. Description of the Related Art It has become a problem that noise (electromagnetic waves) radiated from a printed wiring board on which an electronic circuit is mounted adversely affects electronic equipment with the sophistication of electronic equipment. The electromagnetic interference in question may be caused by an electromagnetic wave generated from the electronic / electrical device itself, or the generated electromagnetic wave may adversely affect the device. Most of the generation sources are electronic circuits. An electronic element that is a component. In the development of electronic and electrical equipment, the failure caused by noise generated from inside the circuit board that constitutes the equipment is a serious problem,
In particular, as the mounting density of boards increases, it is very important to understand the noise generation state of each element.

In order to meet this problem, many measuring instruments such as an electric field strength meter and a spectrum analyzer have been developed and marketed. However, the fact is that the number of devices that directly analyze the state of noise distribution from the mounting state of elements on a board or equipment is very few. Among them, there are commercially available devices that analyze the noise distribution (there is no display on the board) and have the function of a spectrum analyzer. However, this analysis device is directly related to the grasp of noise-generating components. Since it has the function of a spectrum analyzer that does not exist, it has to be an unnecessarily expensive device. Conventionally, a two-dimensional probe scanning device has been provided for grasping the noise occurrence state of a metal housing for electronic devices such as a rack and a cabinet. However, in this device, the outline of the noise leakage state can be grasped. Even if it could be done, it was difficult to grasp the exact positional relationship necessary for specifying the generated parts.

In addition, as a means used for grasping the noise generation state of each element of the electronic component, there is provided a device using an antenna array in which a large number of loop antennas are spread in a grid pattern. However, in this device,
Since there is a limit to the number of antennas that can be mounted, it is possible to know the approximate position of the noise-generating component, but it is difficult to identify the noise-generating component when the components are dense or closely located at that position. Arranging a large number of antennas leads to a strong directivity, and the extension of power feeding to the antennas is different, so that the impedance changes and a measurement error occurs. Since these are originally ambiguous and inaccurate position grasps, in order to specify the parts, it was necessary to correlate and specify the position relationship of the parts and circuit patterns requiring countermeasures based on experience and prediction. Another method is to electronically scan by forming a large number of minute antennas on a printed circuit board, but there are drawbacks in that there is a limit to the array density and the circuit itself becomes very expensive if it is made dense. In a device in which a large number of these antennas are arranged, all are limited to grasping noise of one specific frequency,
Different frequency noises cannot be detected at the same time.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and the state of noise generated from an element forming an electronic circuit is automatically planar-operated by a microprobe. Then, by image processing, the circuit board image stored and displayed on the display in advance is superimposed and the noise intensity and the distribution state are displayed at the same time, so that the parts that generate the maximum noise in the wide frequency range are automatically displayed on the screen. It is intended to provide a means for accurately identifying the noise and solving the noise countermeasure in the electronic circuit design in a short time.

[0006]

In order to solve the above problems, the present invention comprises a noise scanning section S, an image processing section G, a high frequency signal processing section K and a data processing section D. The noise scanning unit S includes a substrate mounting surface 1, and a moving shaft 7 that is freely movable in the X axis direction and the Y axis direction is provided below the substrate mounting surface 1. The microprobe 2 is mounted at one position of the moving shaft 7 in the vicinity of the substrate mounting surface 1, and the encoders 5, 6 in the X-axis direction and the Y-axis direction are mounted on the moving shaft 7. Then, the noise data at the planar position due to the scanning operation is input to the personal computer C, and the distribution state and the intensity of the noise generated from the mounted components are simultaneously displayed on the mounting board image screen and displayed on the output device. Further, the strongest noise source is automatically narrowed down by an electronic control command, the narrowed down portion is displayed on the output device, and the mounted component which is the maximum noise source is specified and displayed.

Further, the frame 8 of the noise scanning section S and the constituent parts of the motors 3 and 4 are made of a material having less noise reflection, and further, parts having less noise are used for the motors 3 and 4. This is to accurately measure the strongest noise source by minimizing the interference and influence of noise from the measuring machine itself on the measuring machine.

[0008]

According to the present invention, the state of noise generated from parts such as an electronic element forming an electronic circuit can be accurately grasped for each part by the microprobe 2. The state of the intensity and distribution of noise captured by the microprobe 2 can be simultaneously displayed by image processing by superimposing it on the electronic circuit board image of the mounted component displayed on the display. In addition, the position of the strongest noise source is automatically narrowed down by an electronic control command, and the narrowed portion is displayed on the output device.
The mounted component that is the maximum noise source can be specified and displayed on the display. When the noise source can be predicted in advance,
The noise intensity at an arbitrary position can be measured by selecting and instructing the periphery of the part displayed on the display. Furthermore, each component is made of a material that reflects or absorbs less noise, and by using parts that generate less noise for the motors 3 and 4 and the encoders 5 and 6, interference of noise from the measuring instrument itself, The influence can be minimized.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawing. In FIG. 1, it comprises a noise scanning section S, an image processing section G, a high frequency signal processing section K and a data processing section D. The noise scanning unit S uses a biaxial table to move a minute probe. A stepping motor is used to drive the XY table, and if necessary, position information is fed back (semi-controlled) to the position information.
Equipped with a Talyen coder. Further, a driver is added according to the capacity of the motor and position control is performed by the computer. Tee
Reflection due to the material of the bull and noise from the motor can cause errors in the measurement system, so select one that is not easily affected. The structure of the present apparatus will be described in more detail. As shown in FIG. 2, the microprobe 2 is mounted on the moving shaft 7 that horizontally changes the position in the X-axis direction and the Y-axis direction below the substrate mounting portion 1. .. Then, the encoders 5 and 6 in the X-axis direction and the Y-axis direction are mounted on the moving shaft 7.

[0010] Both for the case in order to capture accurately the noise generated from the electronic component that needs to be further miniaturized antenna (antenna is large, thereby capturing both noise of a particular component and other components at the same time I can't tell what kind of noise is coming from the parts. Since a small antenna (small probe 2) is used in this device, only the noise of one specific component is captured and is not affected by the noise of other components, so that the noise generating component can be identified. However, it covers a wide frequency band of noise (9 kHz to 1 GHz).
In order to achieve this, if the fine probe 2 is used, the sensitivity remarkably decreases in the low frequency part. Therefore, it is necessary to correct it by the noise processing electronic circuit.

Further, the motors 3 and 4 of the noise scanning section S and the drive device for the motor use parts which generate less noise, and further the motors 3 and 4 and the drive device for the motors. Shielding is applied to the entire surface or ultrasonic wave motor or the like is used. Furthermore, the encoder 5, which outputs the position information,
The magnetic type 6 is also avoided, and the optical type is used to suppress the noise generated from the measuring machine as much as possible. The frame 8 itself, which constitutes the whole, is also a resin-based member. The frame 8 is made of a metal-based material which is superior in strength, but the metal may reflect or absorb the electromagnetic wave and catch an unnecessary electromagnetic wave as a signal. For this reason, it is more preferable to use a synthetic resin which is less likely to reflect or absorb electromagnetic waves and use a conductive plastic.

Next, the image processing section G will be described.
Using the CCD camera F, the printed wiring board 9 as the object to be measured is drawn on the CRT display 11 of the personal computer C. Either the mounting surface (front) or the pattern surface (back) of the component 10 is projected depending on the direction in which the board 9 is set. The image output by the camera F is V in an image processing board (video board) capable of capturing a video signal.
It is converted into RAM data or converted into high resolution by the frame memory and displayed on the display. Next, the high-frequency signal processing unit K will be described. The electromagnetic waves radiated from the object to be measured are captured by the minute probe 2. Micro-
The loop 2 is a microscopic loop or a single needle type, and the band, the distance to the substrate, and the direction are changed according to the purpose. Since the induced high frequency current is originally weak, a wide band high frequency amplifier is provided in advance in order to supplement the sensitivity of the receiver.
Furthermore, the data is input to the high frequency signal processing circuit for frequency analysis and peak processing, and the data is sent to the personal computer C by GPIB.
I shall pass the data. Regarding the data processing unit D, the personal computer C is used for input / output control of data in each processing unit. To print the measurement results, the hard copy is performed by the video printer 12 or the output of Centronics. The measurement data is printed and recorded by the dot printer 13.

Since the CCD camera F has an electronic circuit built-in, unnecessary noise is generated, but since the operation is stopped when the noise of the substrate is detected, it does not affect the noise measurement. This is because at the time of measurement, it is not necessary to operate it at the time of the subsequent measurement because it is first taken from the substrate image (monochrome) CCD camera F through the image processing board to the personal computer C as a still image in the memory once. Is. If necessary, the function of displaying on the display, control of motor, conversion of noise intensity into color data and access to coordinate memory, and color
The converted noise distribution is displayed on the display.

The personal computer C stores the processed board image data in the memory and outputs it to the display 11 as necessary, and the position information from the encoders 5 and 6 is XY.
Conversion to coordinate system, control of driving motors 3 and 4, conversion of electromagnetic wave intensity to color data, access to coordinate memory, and display of colored electromagnetic wave distribution 1
It has a display to 1 and many functions.

The noise captured by the microprobe 2 by the noise processing electronic circuit is converted into a signal that can be input to the personal computer C by this circuit. Further, this circuit has an output for analyzing the frequency component of noise with a spectrum analyzer and a correction function for the minute probe 2. Finally, the color display 11 can simultaneously display the substrate image (monochrome) and the electromagnetic wave generation distribution state (color) and visually check the electromagnetic wave state on the substrate. Also, it outputs to the color printer 13 as needed.

What is necessary for actual noise countermeasures is that it is not necessary to analyze for each frequency, but it is necessary to surely grasp at what position (parts / patterns) what kind of noise is generated. is there. Therefore, the encoders 5 and 6 are attached to the moving section 7 of the noise scanning section S, and the positional information in the X-axis direction and the Y-axis direction at the time of scanning is input to the personal computer C, and the screen of the display 11 or the printer 13 is displayed. Then, as shown in FIG. 5B, the noise occurrence distribution and intensity are simultaneously displayed on the screen. This (a) of FIG.
Shows schematically a board image (monochrome). Circles and squares in the figure represent mounted electronic components. And FIG.
(B) is a color image obtained by superimposing the noise occurrence distribution and intensity (color) on the board image (monochrome), and the portions indicated by meshes, diagonal lines, grid lines, etc. correspond to the noise intensity. It represents a color, and T in the figure is set to a color that is conspicuous at the maximum density, so that the maximum noise generation source can be recognized at a glance.

[0017]

[Operating Procedure] The printed circuit board 9 to be tested is set on the circuit board mounting portion 1, and the circuit board 9 is put in an operating state by applying power, signals and the like. The board image is taken into the personal computer C by the CCD camera F (TV camera). The video signal is processed by the image processing board mounted in the slot of the personal computer C and stored in the memory as video data to obtain the size and area of the substrate 9. At this time, the minute probe 2 is placed at a position (origin) that does not affect the board image. After inputting the image, CC
The power of the D camera F (TV camera) is set to "off". This is to prevent the high frequency noise generated by the CCD camera F from being caught by the minute probe 2.

Next, the frequency band, the resolution bandwidth, the probe movement width, etc. are input, and as shown in FIG. 3, the operation modes of the following (1) to (3) are freely selected and measured. Set the conditions. (1) Auto search mode (shown in (a) of FIG. 3) Designate an arbitrary range and the division number n while observing the board image,
Divide to find the maximum radiation area. Next, the maximum radiation area is limited and divided into n and searched. Further, the same repeated search is performed, and the noise source is narrowed down until the moving interval of the probe becomes 10 mm or less. The broken line cells represent the resolution bandwidth, the circles are the measurement points, and the line connecting the circles is the locus of the antenna. The broken line meshes shown in FIG. 3A indicate that the resolution bandwidth is narrowed toward the noise source and narrowed down. (2) Auto-scan mode (shown in (b) of FIG. 3) An arbitrary range is designated while observing the board image, and automatic measurement is performed by dividing. (3) Manual search mode (shown in (c) of FIG. 3) The user selects and measures an arbitrary position while watching the board image. When the mounting density of parts is high in any of the above modes,
The movement width is made fine, and the movement width is set to be coarse when the mounting density is low. The moving interval of the probe can be specified with any width.

When the noise scanning device moves in the X-axis direction and the Y-axis direction, when the component mounting density is high, the scanning is performed by reducing the scan density of the scanning lines as shown in FIG. When is low, the scan density is made coarse as shown in FIG. As shown in this scan, the microprobe 2 moves on the substrate 9, captures the noise generated from the parts / patterns, is sent to the noise processing electronic circuit, is analog / digital converted, and is the memory of the personal computer C.
Memorized in. At the same time, the position data is also sent to the personal computer C by the encoders 5 and 6 attached to the X-axis and Y-axis motors 3 and 4 and stored in the memory. It is also possible to directly use the signals for driving the data 3 and 4 as the position data. At this time,
The frequency characteristics of B2 should be calibrated.

Image data from the CCD camera F (schematically shown in FIG. 5A) and digitized noise data.
By simultaneously displaying the data on the display 11 (shown schematically in FIG. 5B), the noise distribution and the intensity generated on the substrate 9 can be determined by comparing the noise generation position and the noise generation position on the actual part / pattern image. The intensity is displayed in different colors. From the above results, the state of noise from each electronic component / print pattern can be grasped promptly, so that noise countermeasures can be taken promptly after board design. By inputting the noise frequency distribution and the accurate intensity to the spectrum analyzer from the noise processing electronic circuit, it is possible to know the more accurate noise state.

[0021]

As described above, the present invention can automatically identify the position of noise emitted from the printed wiring board 9 on which an electronic circuit is mounted. Therefore, the layout of the components 10 and the circuit pattern can be reviewed. Noise countermeasures can be solved in a short time at the prototype stage. In particular, by mounting the image processing device by the personal computer C using the minute probe 2, the noise intensity and the noise distribution state are overlapped in detail and the display 11 is simultaneously displayed.
Can be displayed on the screen, the position where noise is generated can be grasped at a glance, and the parts can be identified immediately and accurately. Furthermore, the automatic narrowing-down function can automatically identify and display the maximum noise generating component in the specified area. Further, by using a material having no metal reflection or a low noise component, it is possible to minimize the interference and influence of noise from the component, and to capture a more accurate noise distribution state. In other words, with this device, it is possible to reduce the cost of the product because it can be configured with countermeasure components with little improvement in reliability in a noise environment.
It will be possible to improve the utilization efficiency of the site and anechoic chamber and significantly shorten the development cycle.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing the configuration of hardware in an embodiment of the device of the present invention.

FIG. 2 is a schematic diagram showing a system configuration in an embodiment of the device of the present invention.

FIG. 3 is a schematic diagram showing the operation of a microprobe.

FIG. 4 is a schematic diagram showing a moving interval of the probe due to a difference in mounting density.

FIG. 5 is a schematic diagram showing a noise distribution radiated from a substrate, (a) is a schematic diagram showing a video screen of a printed wiring board, and (b) is a schematic diagram showing a state in which the noise distribution is superimposed on the video screen of the printed wiring board.

[Explanation of symbols]

 S noise scanning section G image processing section K high-frequency signal processing section D data processing section F board image data input CCD camera C personal computer 1 board mounting section 2 microprobe 3 motor 4 motor 5 Encoder 6 Encoder 7 Moving Axis 8 Frame 9 Printed Circuit Board 10 Parts (Electronic Element) 11 Display 12 Video Printer 13 Dot Printer 14 Personal Computer Body

Claims (2)

[Claims] 1. A noise scanning section S, an image processing section G, a high frequency signal processing section K and a data processing section D, wherein the noise scanning section S is a substrate mounting surface (1).
And a moving shaft (7) that is freely movable in the X-axis direction and the Y-axis direction is provided below the substrate mounting surface (1), and the substrate mounting surface (1) is provided at one position of the moving shaft (7). ), A microprobe (2) is mounted in proximity to the moving shaft (7), and encoders (5) and (6) in the X-axis direction and the Y-axis direction are mounted on the moving shaft (7),
The noise data at the planar position by the scanning operation is input to the personal computer C, and the distribution state and the intensity of the noise generated from the mounting components are simultaneously output and displayed on the mounting substrate image screen, and the instruction of the electronic command system is given. A noise finder device that automatically narrows down the strongest noise source in a designated section and displays the mounted component that is the noise source. 2. The frame (8), motors (3), (4) of the noise scanning section S are made of a material having less noise reflection, and further, the motors (3), (4). 2. The noise finder device according to claim 1, wherein a component that generates less noise is used for the noise finder.