JPH04125478A - Noise application induction device - Google Patents

Abstract

PURPOSE:To enable noise-application part to be selected and specified thinly and components which are weak against noise to be analyzed by providing a plurality of noise-application parts and enabling them to be switched selectively. CONSTITUTION:Pulse signal is received by a coaxial connection plug 4 through a coaxial cable and connectors 10 and 11 from a noise simulator 9, thus enabling a line current 12 to be flown around a surface of a noise-application wire 1 and pulse signal to be induced as a noise signal at a pattern of a printed-circuit board 7 on an insulation plate 5 due to the electromagnetic induction operation. Then, malfunction or improper operation occurs on the printed-circuit board 7, it can be determined that the pattern or electronic parts are weak against noise. Then, by switching the connector 11 for connection plug 4 in vertical or horizontal direction in sequence, electromagnetic induction operation can be induced at the connection plug 4 of each application wire 1, thus enabling a part which is weak against noise to be traced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a noise application induction device that can apply noise from a noise simulator to a printed circuit board on which electronic components are mounted to determine which parts are susceptible to noise. It is something.

[Prior Art] Noise evaluation tests for electrical products are generally conducted when the electrical product is completed. but.

When evaluating the entire product when the electrical product is completed, it is already in the final stage of development, so there are limitations in the processing of countermeasures for one problem, and at the same time there are problems such as a loss of one hour. Therefore, in recent years, there has been an increasing demand for noise application and induction devices that can implement noise evaluation at the level of printed circuit boards on which electronic components are mounted, and can make product judgments and consider countermeasures.

Under these circumstances, Japanese Patent Application Laid-Open No. 64-116467
The conventional noise application induction device that became known in the publication No. 6
This will be explained using the cross-sectional view shown in the figure, the overall wiring diagram shown in FIG. 7, the partial diagram showing the noise current distribution shown in FIG. 8, and the voltage waveform diagram shown in FIG.

In the figure, two of the upper metal plate (1) and lower metal plate (2) are shown.
Two metal plates are arranged in parallel at intervals of about 16 mm, an insulating plate (5) is arranged on the upper surface side of the upper metal plate +11, and the legs (61, (61) are placed on this insulating plate (5). The structure is such that a printed circuit board (7), which is the test object, is placed between these two upper metal plates (11 and lower metal plate (2)).
In between is a lead wire (16).

(17) are electrically connected to each other, and one end of these lead wires (16) and (17) is connected to a coaxial plug (4).
) are connected. Then, the pulse signal output from the noise generator (hereinafter referred to as noise simulator) (9) that generates the pulse signal shown in Fig. 7 is received by the coaxial plug (4) via the coaxial cable (10). It is supposed to be done. Also, the upper metal plate (1) and the lower metal plate (2
Lead wires (161, f171 are electrically connected to each other, and lead wires 81. A plug (20) is provided.

The socket (21) to be inserted and connected to this plug (20)
) side, a 500Ω termination resistor (3) is connected to prevent the pulse signal from being reflected.

In the noise simulator (9), a socket (not shown) is provided on the coaxial cable (10) that conducts the pulse signal, and the socket is connected to the coaxial plug (4) provided in the noise application induction device by pushing it. It is configured.

Next, the operation will be explained. Since the conventional noise induction device is wired as shown in Figure 7, the pulse signal (Figure 9) output from the noise simulator (9) is connected to the coaxial cable (10) and the socket (not shown). when received by the coaxial plug (4) through the upper metal plate (11
As shown by the arrow in Figure 8, there is a plug (2
A surface current (22) flows in the 0) direction. This surface current (22
) further passes through the lower metal plate (2) and connects to the coaxial plug (
4) via socket (not shown), coaxial cable (l
O) and return to the noise simulator (9). When a surface current (22) flows through the upper metal plate (1), the electromagnetic induction effect of this surface current (22) causes a pulse to be applied to the pattern or component of the printed circuit board (7) placed on the upper metal plate (1). The signal is mixed in as a noise signal.

In this way, the test object induces a noise signal to the printed circuit board (7), confirms the operating state of the printed circuit board (7), evaluates noise resistance, and identifies unsuitable parts and installs new bypass capacitors. Various noise countermeasures have been taken for the printed circuit board (7).

[Problems to be Solved by the Invention] In the conventional noise application induction device, the upper metal plate to which noise is applied is constituted by a flat surface. The entire surface of the printed circuit board receives induction, and although it is suitable for testing to determine pass/fail for each printed circuit board, it is not possible to identify the location where the noise is applied, so it is difficult to determine which parts of the printed circuit board are vulnerable to noise. There were problems such as difficulty in analysis.

This invention was made in order to solve the above-mentioned problems, and it is possible to selectively specify the parts of the printed circuit board to which noise is applied, which is the test object, in detail. The purpose of this invention is to obtain a noise application induction device that can be used to analyze whether the noise is weak or not.

[Means for Solving the Problems] In the noise application and induction device according to the present invention, a noise application line and a lower metal plate are arranged in parallel at a predetermined interval.

A noise application and induction device that applies a pulse signal between the noise application line and the lower metal plate to apply and induce noise to a printed circuit board placed on the noise application line,
An end of the lower metal plate is bent, and a pulse application section for applying a pulse signal between the noise application line and the lower metal plate is provided at one of the bent ends, and the noise application line is on the opposite side of the pulse application section. A terminating resistor is connected between the noise applying line and the lower metal plate, a plurality of the noise applying lines and the pulse applying section are provided, and one of the noise applying line and the pulse applying section can be selected.

[For use] In this invention, it is possible to selectively switch the noise application part of the printed circuit board that is the test object, so it is possible to selectively specify the noise application part of the test object in detail, and to determine which part of the printed circuit board is affected. You can analyze whether parts are susceptible to noise.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings. In Figure 1, (1) is a noise application line made of a conductor instead of a metal plate, and the lower metal plate (2) made of aluminum is placed at a distance of about 16 mm from the noise application line (1). They are arranged in parallel, and both ends of 9 are bent upward by 90 degrees to form a starting end (2a) and a terminal end (2b). Attach the coaxial plug (4) to the starting end (2a) of this lower metal plate (2). A terminal resistor (3) is attached to the terminal end (2b) of the lower metal plate (2).
) to connect. Connect the coaxial connection (4) and the terminating resistor (3) with a noise applying wire. An insulating plate (5) for electrical insulation is placed on the top side of the noise application line (1).
) are placed on both ends (2a) and (2b) of The structure is such that a printed circuit board (7) as a test object is placed on this insulating plate (5) with legs (6) interposed therebetween. Supporting materials (8) are arranged at both inner ends of the noise application line (1) and the lower metal plate (2), and the noise application line (1) is connected to the lower metal plate (2).
It plays the role of keeping it parallel and equidistant from the

A pulse signal is generated by the noise simulator (9) shown in FIG. 2 and output to the coaxial connector (11) through the coaxial cable (lO). A pulse signal from the coaxial connector (11) is connected to the coaxial plug (4) and supplied to the noise application line (1). On the opposite side of the noise applying line 11), it is connected to the lower metal plate (2) through a 50Ω terminating resistor (3) so that the pulse signal is not reflected. As shown in FIG. 3, the plurality of noise application lines (1) are configured to connect mutually opposing ends of the lower metal plate (2) and to be perpendicular to the vertical and horizontal directions. Coaxial plug (4)
are provided on the starting end side of each noise applying line (1).

Next, the operation of this embodiment described above will be explained with reference to the drawings. The noise applying and inducing device of the embodiment configured as described above is wired as shown in FIG. 2 or 3.

Noise simulator From (9) 1 For example, rise time i
When a pulse signal with a pulse width of 350 ns is received via the coaxial cable (10) and the coaxial connector (ill) at the coaxial connector (4), the noise applying wire (11) is connected to the coaxial connector (4) around the surface. A line current (2) flows in the direction of the arrow from the side toward the terminating resistor (3).
12) performs matching to prevent reflection by the terminating resistor (3), and at the same time, as shown in Figure 4, the terminating resistor (3)
3) While maintaining the steep rise characteristic of the voltage at both ends,
Passing through the lower metal plate (2) and through the coaxial plug (4),
It passes through the coaxial connector (11), the coaxial cable (10) and returns to the noise simulator (9). When a line current (12) flows through the noise applying line (wire), this line current (12)
A pulse signal is induced as a noise signal into the pattern of the printed circuit board (7) placed on the insulating plate (5) by the electromagnetic induction effect. In other words, an environment is intentionally created where malfunctions and runaways are likely to occur. As a result, if.

If a malfunction or runaway occurs in the printed circuit board (7), it can be determined that the pattern or electronic component located above the noise application line fil is susceptible to noise. According to this device, electromagnetic induction is applied to each noise applying line (1) by sequentially selectively switching the coaxial connector 1) to the coaxial plug (4) of the vertical or horizontal noise applying line (1). This makes it possible to track areas that are susceptible to noise.

Intent: Similar to the prior art described above, bypass capacitors and the like are newly provided to take measures against noise on the printed circuit board (7).

A modification of this embodiment is shown in FIG. In the figure, the noise application line (1) and the lower metal plate (2) are fixed, and the printed circuit board (7) of the test object can be moved in the direction of the arrow (al or b1) shown in the figure. Therefore, the insulating plate (5
) according to the width of movement of the printed circuit board (7), and the legs (6) are placed on the insulating board (7) while placing the printed circuit board (7).
5) The structure should be such that it can be moved continuously in a direction perpendicular to the extending direction of the noise applying line by means of a cart or sliding on the top.

In this way, by further rearranging the printed circuit board (7) vertically and horizontally, it becomes possible to continuously apply noise throughout the printed circuit board (7) vertically and horizontally.

If a linear distribution that is susceptible to noise is found when moving in the vertical direction, and a linear distribution that is similarly susceptible to noise is found when moving in the horizontal direction, the intersection of the two is determined to be a location that is susceptible to noise. here,
If the noise application point selection function shown in the embodiment is a static step-by-step function, the noise application point selection function shown in the modification is a dynamic continuous function, and the present invention has both of the above functions.

As explained above, in the noise application induction device of this embodiment, the terminating resistor (3) is 50Ω;
) is not a resistance value limited to 50Ω (.

It is possible to change it as appropriate. Also, the noise application line (1
1 has three horizontally and five vertically, but depending on the size of the lower metal plate (2) and in order to improve selection accuracy, a large number are required, so there is no limit to the number. In addition, by arbitrarily changing the rise time and pulse width of the pulse signal output from the noise simulator (9),
) It goes without saying that the voltage waveform of the noise induced in the pattern can be changed.

In addition, the starting end (2a) and the ending end (2b) of the lower metal plate are folded back as shown in the figure, but this is done in consideration of the ease of switching between the coaxial plug (4) and the phase connector (11). It is possible to obtain the same electrical performance even if the plate is folded straight or flat.

In addition, as shown in Figures 2 and 3, the noise application lines (1) are arranged vertically and horizontally, but if the printed circuit board (7) of the test object is replaced vertically and horizontally, the noise Application line (
It is clear that 11 can be used in either the vertical or horizontal direction.

In addition, although the lower metal plate (2) has been described as an example of aluminum, the lower metal plate (2) corresponds to the return path of the noise signal line, and is preferably a material with low impedance, and may be made of copper or the like. .

Furthermore, as a modified example, a configuration was shown in which the noise application line is fixed and the printed circuit board (7) of the test object is moved, but this is reversed, and the noise application line is fixed and the noise application line is moved. may be moved, and the same effect can be achieved if the relative positional relationship between the two is fixed.

[Effects of the Invention] As described above, according to the present invention, a noise applying line and a lower metal plate are arranged in parallel at a predetermined interval, and a pulse signal is applied between the noise applying line and the lower metal plate to reduce the noise. In a noise application and induction device that applies and induces noise to a printed circuit board placed on an application line, an end of the lower metal plate is bent.

A pulse application section for applying a pulse signal is provided between the noise application line and the lower metal plate on one side of this bent end, and a terminating resistor is connected between the noise application line and the lower metal plate on the opposite side of the pulse application section. However, since a plurality of noise application lines and pulse application sections are provided and one of the noise application lines and pulse application lines can be selected, the noise application part of the printed circuit board to be tested can be subdivided. This has the effect of providing a noise application and induction device that can selectively specify and analyze which parts of a printed circuit board are vulnerable to noise.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the noise application and guidance device according to the present invention, FIG. 2 is an overall wiring diagram of the noise application and guidance device of the invention, and FIG. 3 is a perspective view of the noise application and guidance device of the invention. FIG. 4 is a voltage waveform diagram across the terminal resistor of the noise application induction device of the present invention, FIG. 5 is a wiring diagram of a modified example of the invention, FIG. 6 is a sectional view of a conventional noise application induction device, and FIG.
The figure shows the overall wiring diagram of a conventional noise applying induction device, Figure 8 is an explanatory diagram showing the surface current flowing through the upper metal plate of the conventional noise applying induction device, and Figure 9 shows both ends of the terminating resistor of the conventional noise applying induction device. FIG. 1... Noise application line, 2... Lower metal plate, 2a.
...Starting end of the lower metal plate, 2b... Terminating end of the lower metal plate. 3... Terminal resistor, 4... Coaxial plug, 7... Printed circuit board, 10... Coaxial cable, 11... Coaxial connector Note that the same reference numerals in the drawings indicate the same or equivalent parts.

Claims (1)

[Claims] A noise applying line and a lower metal plate are arranged in parallel at a predetermined interval, and a pulse signal is applied between the noise applying line and the lower metal plate to apply and induce noise to a printed circuit board placed on the noise applying line. In the application guidance device, an end of the lower metal plate is bent, a pulse application section for applying a pulse signal between the noise application line and the lower metal plate is provided on one of the bent ends, and the opposite side of the pulse application section is provided. A terminating resistor is connected between the noise applying line and the lower metal plate, a plurality of noise applying lines and pulse applying parts are provided, and one of the noise applying line and the pulse applying part can be selected. Characteristic noise application induction device.