JPS6283672A - Method for detecting noise of earth line - Google Patents

Abstract

PURPOSE:To make it possible to easily and accurately measure insert noise over the total length of an earth line, by detecting noise induced in the earth line using a transient phenomenon measuring circuit. CONSTITUTION:When the noise of an earth line AL is detected, the transient phenomenon measuring circuit 1 of a noise detector F is mounted to the earth of an apparatus B. When voltage caused by disturbance is induced in any area of the line AL over the total length from the earth of the apparatus B to an earth station C, a transient current It flows to the measuring circuit 1. This current It is taken out as voltage by a resistor to be applied to a voltage signal display device 2 and the variation value of a display value is read to detect the insertion of noise and the intensity thereof.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a ground line noise detection method for measuring noise inserted into the ground line of equipment that requires grounding in a narrow sense, and a line noise detection method in a broad sense. .

(Prior Art) Conventionally, there are two methods for measuring noise inserted into a ground line. This will be explained using FIG. 4.

In Figure 4, A is the casing, B is the equipment that requires grounding housed in the casing A, AL is the ground line, C is the ground between the underground, and D is the ground between the grounds inside the casing A. , El and E2 are synchronoscopes, respectively.

This is a noise-side regulator for digital voltage measurements, etc.

Conventionally, the first method of measuring the noise of the earth line AL is to insert a probe P fixed to the tip of one side of the conductor extended from the noise measuring device E1 into the vicinity of the ground C, while the other side is connected to the other side of the conductor. Connect to device B, and detect noise between device B and ground C. The second method is to connect one side of the conductor of noise measuring device E2 to the ground in housing A and the other side to device B, and detect noise between device B and the ground. .

(Problems existing in the prior art) In the case of the first conventional method described above, it is necessary to insert the probe P underground and create a new underground space.
Since the earth line AL between the measurement point and the ground C/device B is usually several tens of meters apart, there is a high possibility that electromagnetic waves will be induced into the conductor extended from the noise measuring device E1, causing noise that is louder than the actual noise. It will be measured. Moreover, the noise caused by the electromagnetic waves is easily influenced by the surrounding environment such as the thickness and length of the conductor, the wiring condition, etc.
The surrounding environment factors will differ for each measurement,
It is difficult to expect accurate noise detection.

In the case of the second conventional method described above, although the trouble of installing a new underground grounding station C can be saved, even if the noise between the equipment B and the grounding station in the housing A can be detected, it requires a long distance as described above. Since the noise that is naturally supposed to be inserted into the ground line AL between the ground line D in the housing A and the ground line C in the ground is not subject to detection, the obtained measured value is worthless.

(Object of the Invention) The present invention has been made in order to solve the above-mentioned problems of conventional detection methods when detecting noise inserted into the ground line of equipment that requires grounding. It is an object of the present invention to provide a ground line noise detection method capable of immediately, easily, and accurately measuring noise inserted over the entire length of a ground line without requiring any effort.

(Structure of the Invention) The structure of the present invention is that when measuring noise inserted into the ground line of a device that requires grounding, a transient phenomenon measurement circuit capable of measuring transient current is installed at a predetermined position of the ground line of the device. A method for detecting ground line noise is characterized in that the transient current flowing through the circuit is extracted as a voltage, the voltage is displayed on a voltage signal display, and noise is measured from the fluctuation.

(Function of the Invention) The present invention utilizes the fact that noise has an element of a transient phenomenon to absorb the transient current generated by the noise inserted over the entire length of the earth line at a point attached to a predetermined position on the earth line. This has the effect of measuring the noise from the fluctuation of the voltage signal by capturing it as a voltage and displaying it as a signal.

(Example).

The present invention will be described in detail below according to the embodiment shown in FIGS. 1 to 2(c).

In FIG. 1, A is a housing, B is a device that requires grounding, C is a grounding point in the ground, D is a grounding gap in the case A, AL is a grounding line, and F is a grounding line using the method of the present invention. This is the earth line noise detector implemented.

The ground line noise detector is comprised of a transient phenomenon measuring circuit 1 and a voltage signal display 2, as shown in FIG. 2(a). The transient phenomenon measuring circuit I is composed of a circuit in which a capacitor C is connected in parallel with a coil L and a resistor R, and the voltage between the circuits sandwiching the resistor R is taken out.

The voltage signal display 2 is capable of displaying the voltage taken out from the transient phenomenon measurement circuit 1.

When detecting noise on the ground line AL, the transient phenomenon measurement circuit 1 of the ground line noise detector F is attached to the ground of the device B, for example. As a result, if a voltage due to a disturbance is induced in any part of the earth line AL extending over the entire length from the earth of the device B to the ground C, a transient current It flows in the transient phenomenon measurement circuit 1 according to the arrow. Therefore, since the voltage can be taken out via the resistor R that is set in a predetermined manner, the insertion of noise and its strength can be detected by reading the voltage fluctuation value from the signal output of the voltage signal display 2. becomes.

In this case, for example, increase the impedance of the resistor R by 1°
゛, the voltage value between the circuits sandwiching the resistor R becomes large,
Furthermore, if the impedance of the coil L is increased, the width of the voltage between the circuits sandwiching the resistor R will be increased, but the voltage can be detected in either case.

As mentioned above, the resistance R is an important element when extracting and detecting the voltage from the transient current, so the transient phenomenon measurement circuit 1
is not limited to the three elements shown in Fig. 2(al), but may include the coil L and resistor R as shown in Fig. 2(b), or only the resistor R as shown in Fig. 2(c). It is also possible to configure the circuit with That is, since the insulating component (the insulating component due to the loop between the circuits) and the inter-line C component are generated even if the coil L is not included, elements other than the resistor R can be omitted.

(Application example: 1) FIG. 3(a) shows an application example in which an earth line noise detector F implementing the method of the present invention is incorporated on a printed circuit board.

Reference numeral 3 denotes a printed circuit board having the same dimensions as the printed circuit board housed in the printed circuit board storage case of device B that requires grounding.The transient phenomenon measurement circuit 1 is formed at a predetermined position on the printed circuit board 3, and the input This is an earth line noise detection board in which the side is connected to the earth path line G and the voltage signal indicator 2 is attached to the edge in the direction of the door. With the above configuration, simply by inserting the printed circuit board 3 into the motherboard, the ground pass line G is connected to the ground line AL, so that detection of noise inserted into the ground line AL can be performed with a single touch. .

(Application example: 2) Figure 3(b) was devised by the inventor prior to filing the main application,
Utility Application No. 60-68228 and Utility Application No. 60-116
"Electromagnetic Noise Detection Board" published in issue No. 584
This is also an application example in which the method of the present invention is applied to a technology related to a "printed circuit board supply power supply noise detection board."

In the figure, numeral 30 is a noise integrated detection board manufactured using a printed circuit board, and a transient phenomenon measurement circuit 1 is formed at a predetermined position on the board 30.

A voltage signal indicator 2 is attached to the edge in the direction of the door, a power supply voltage detection circuit 4 is formed at another predetermined position, and an electromagnetic noise detection sensor 5 consisting of a closed loop antenna of a size that fits within the dimensions of the board 30 is installed. Paste it on the board 30. The ground path line G is connected to the transient phenomenon measurement circuit 1 and one input side of the power supply voltage detection circuit 4, and the other input side of the power supply voltage detection circuit 4 is connected to the power supply path line V (
For example, connect to a 5V line). A display section 41 is attached to the edge in the door direction and displays the measured value of the power supply voltage detected by the power supply voltage detection circuit 4, and is attached to the edge in the door direction for ease of reading.

Reference numeral 51 also attached to the edge of the door is an electromagnetic noise detector for detecting electromagnetic waves caught by the electromagnetic noise detection sensor 5, and 52 is an indicator for displaying electromagnetic noise.

By simply inserting the noise integrated detection board 30 configured as described above into the motherboard, 1il can be connected to the ground line AL.
Detection of noise applied to the power supply side supplied to the printed circuit board from fluctuations in the measured power supply voltage, and noise induced from electromagnetic waves entering the insertion position of the board 30 are simultaneously detected. Each can be detected accurately.

(Application example: 3) The method of the present invention connects the transient phenomenon measurement circuit 1 to the power supply line (
It does not matter whether it is AC or DC) or if it is installed at a predetermined position on a signal line and used as a measurement point, the noise inserted on these lines will cause the transient phenomenon measurement circuit 1 to
t, so that the line noise of the power supply line or the line noise of the signal line can be detected from the voltage signal in the same way as the ground line noise detection described above.

Therefore, although the present invention includes a ground line noise detection method in the title and claims, the ground line noise detection is merely an example, and is essentially nothing but a line noise detection method.

(Effects of the Invention) The method of the present invention does not require a base station (earthed station) and only requires one measuring point. Therefore, the probe conductor used for measurement can be short or short, so it does not depend on the environmental conditions. It is possible to extremely easily and accurately detect noise inserted over the entire length of the ground line A, which eliminates the influence of electromagnetic waves that greatly influence the noise.

Furthermore, the circuit configuration is simple, and as shown in application example 2, electromagnetic noise detection and power supply voltage noise detection can be installed on a board made of a printed circuit board. It is now possible to directly and accurately detect all noises that have an adverse effect on equipment simultaneously but individually, allowing the pursuit of the cause of noise generation and taking appropriate measures to eliminate it, which is extremely effective in avoiding malfunctions caused by equipment noise. Magnify the effect.

Further, since the method of the present invention can be applied to power supply lines and signal lines to detect noise inserted into these lines, the method can be used as a line noise detection method that can be used in an extremely wide range of applications.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the method of the present invention, and FIG. 2 (a
) is a circuit diagram showing an example of a transient phenomenon measuring circuit implementing the method of the present invention, FIGS. 2(b) and (c) are diagrams showing other embodiments of the transient phenomenon measuring circuit used in the present invention, and FIG. Figures (a) and (b) are front views of application examples 1 and 2 of the present invention, respectively, and Figure 4 is a block diagram illustrating a conventional ground line noise detection method. B --------------- Device A L --------- Earth line Ir ----- Transient current I------ Transient phenomenon measurement circuit 2-・−・
・-Voltage signal display

Claims (1)

[Claims] When measuring noise inserted into the ground line of a device that requires grounding, a transient phenomenon measurement circuit capable of measuring transient currents is installed at a predetermined position on the ground line of the device, and the transient current flowing through the circuit is converted into a voltage. 1. A method for detecting ground line noise, comprising: extracting the voltage, displaying the voltage on a voltage signal display, and measuring noise from fluctuations in the voltage.