JPH0414913A - Environmental electromagnetic noise monitor - Google Patents

Abstract

PURPOSE:To easily detect the frequency and the level of a wave consecutive for a short time by using a signal whose period is shorter than the consecutive time of the wave consecutive for a short time as the control signal to be applied to either or both of a variable capacitive elemet or a variable inductive element of a resonance circuit so as to sweep the monitor, and obtaining the frequency and the level of the wave consecutive for a short time based on the tuning output resulting from the sweep. CONSTITUTION:When each output comes from a tuning frequency detection circuit 28, a level comparator circuit 26, a NAND circuit 29 and a pulse generating circuit, then via a CW control unit 32, information such as a time, a frequency, a peak level and the number of times of the arrival is outputted to a display section 19 by the control of a main control section 20 and the information is printed out by a printer. Thus, when the level of a wave consecutive for a short time CW exceeds a preset level V0, an automatic tuning circuit 23 is automatically tuned with the wave, the information of noise such as a time, a frequency, a peak level and the number of times of the arrival is displayed on the display section 19 in on-line and printed out by the printer sequentially. Thus, factors of the arrived noise are easily grasped.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to the case where, when a failure occurs due to external noise in a communication device such as a telephone connected to a communication line, noise from the communication line or power line of the communication device is detected. The present invention relates to an environmental electromagnetic noise monitoring device that monitors an intrusion route for a predetermined period of time to enable early identification of the cause of a failure.

"Prior Art" Conventionally, as this type of monitoring device, one such as shown in the connection diagram of the incoming noise monitoring system shown in FIG. 7, which targets power lines, has been used.In other words, in FIG. 1 is the power line installed in the office or user's home, 2 is the power line 1
3 is a home appliance that is different from the fault monitoring target device 2 connected to the power line 1, such as home appliances, office equipment, or OA equipment, and the switching operation when it is activated. 4 is an indoor noise source that sends noise to the power line 1; 4 is an outdoor noise source such as a power device connected to the power line L; 5 is a failure of the monitored device 2 This is a power supply noise monitoring and recording device that is connected to the power line 1 of the monitored device 2 and monitors incoming noise when it occurs.

FIG. 8(a) shows that in the power line wiring system shown in FIG. 7, noise from an indoor noise source 3 and an outdoor noise source 4 that occurs during startup and shutdown is transmitted through the power line 1 and reaches the monitored device 2. This is a typical noise waveform that can cause problems such as equipment malfunction.

When a failure occurs in the monitored device 2 in the system shown in FIG. 7, the level of the noise waveform (pulse peak value) and arrival time,
In order to grasp the frequency etc. at an early stage, there is a method of connecting the power supply noise monitoring and recording device 5 to the power line 1 of the monitored device 2 as shown in FIG. , has been used more widely than before.

``Problems to be Solved by the Invention'' However, in this type of noise monitoring and recording device according to the above-mentioned conventional technology, when trannoenotopulsic noise as shown in FIG. 8(a, ) arrives, the noise factor is It can be detected and recorded, but if the incoming noise continues for a short time, the frequency and level cannot be detected properly.For example, when communicating when a vehicle equipped with a high-output CB radio passes by. The transmitted noise disappears after the vehicle passes, and becomes a short-time continuous wave (U duration tL) as shown in Fig. 8(b).
). Further, electromagnetic waves of a certain level may arrive intermittently as shown in FIG. 8(c). In devices such as button telephones, which are wired with communication lines such as office lines and extension cables in addition to power lines, the arrival noise of these short-term continuous waves enters the equipment from the office lines and extension cables. Causes failures such as malfunctions and line disconnections. In order to implement noise countermeasures with these devices, it is necessary to quickly find out the intrusion route, frequency, and level of short-term continuous waves such as those shown in Figure 8 (b) and (c) from the office line and extension line. However, the conventional power supply noise monitoring and recording device 5 shown in FIG. 7 has a drawback in that it cannot detect these noise factors.

The present invention aims to solve the above-mentioned drawbacks. It is possible to independently and automatically detect short-time continuous waves as shown in Figures 8(b) and (c) and transient pulse waves as shown in Figure 8(a), which may cause failures in communication equipment. The purpose of the present invention is to provide a possible environmental electromagnetic noise monitoring device.

I-Means for Solving the Problem] The configuration of the environmental electromagnetic noise monitoring device of the present invention to achieve the above object is as follows: When a failure occurs in a communication device due to external noise, the noise intrusion path is monitored and the incoming noise factor is monitored. In an environmental electromagnetic noise monitoring device, for short-term incoming noise that has a predetermined frequency and continues for a certain period of time and then stops, the circuit constants of either or both of the capacitive element and inductance element that constitute the resonant circuit must be adjusted. is continuously variable by automatic sweeping at a period equal to or less than the duration of the incoming noise, and when the incoming noise is input to the resonant circuit and exceeds its output level or a predetermined set level, the voltage of the automatic sweep is changed. means for determining the frequency of the input wave of the incoming noise and outputting it together with the level of the input wave and other incoming noise factors; and means for outputting the level of the input wave together with other arriving noise factors.

[Operation] The present invention continuously changes the circuit constant of one or both of the capacitance element and the inductance element constituting the resonant circuit by automatic sweeping, and the period of the sweep at this time is changed from the duration of the incoming noise. input the incoming noise to be monitored into the resonant circuit, determine the frequency of the input wave of the incoming noise from the tuned output level of the resonant circuit, and if the output level exceeds a predetermined set level. By outputting the frequency and level of the input wave only when the input wave is detected, the frequency and level of short-time continuous wave noise, which is normally difficult to detect, can be easily detected.

In addition, in addition to the above, other noise factors, such as the time and number of arrival noises (frequency), such as the time and number of times (frequency) of incoming noise, such as pulse noise, can be independently detected on the route side. By doing this, it is possible to set the setting level of each noise detection according to the failure level of the monitored device for each path, and by looking at the output results, it is possible to determine ``which path, what kind of noise, and what kind of noise is coming from. To easily understand noise factors such as whether a failure occurs because the arrival time is on time.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

First, the incoming noise monitoring state of the environmental electromagnetic noise monitoring device of the present invention will be explained. FIG. 1 is an explanatory diagram of the same. 1 is an external power line, 6 is a monitored device such as a communication device, 7 is an indoor communication line of the monitored device 6, and 8 is an indoor communication line connected to an external communication line. An indoor low set for connecting the communication line 7, 9 an indoor power line for supplying power from the external power line 1 to the monitored device 6, 10 a noise source equipped with a high-output CB radio, etc., 11 12 is an environmental electromagnetic noise monitoring device according to the present invention; 13 is a current probe or high impedance probe for detecting noise arriving at the monitored device 6 from the communication line 7 or the power line 9; The noise detection means 14 is an antenna provided in the environmental electromagnetic noise monitoring device 12 according to the present invention for detecting spatial noise around the device 6 to be monitored.

When a failure occurs in the monitored device 6 in FIG. After connecting to the noise monitoring device 12 and setting in advance the failure occurrence level of the monitored device 6 with respect to intrusion noise from each path, monitoring of intrusion noise is started. When noise exceeding each failure occurrence level arrives, the frequency, level, peak value, and level are printed out along with the arrival time of each noise, thereby identifying the cause of the failure when it occurs in the monitored device 6. To enable the type of noise, level 1 frequency, and 1 time to be known early and easily.

Next, the configuration of the environmental electromagnetic noise measuring device 12 of the present invention used above will be explained. FIG. 2 is a block configuration diagram showing one embodiment thereof. In the configuration of this embodiment, 15 is a noise short-time continuous wave (CW) detection unit having a constant frequency as shown in FIGS. 8(b) and 8(c), 16 is an input terminal of the CW detection unit 15, and (7) is a transient pulse wave (pLs) detection unit as shown in FIG. 8(a), +8
The input terminal of the tPLs detection unit 17, 19 is a display section for displaying the detection signals of the CW detection unit 15 and the PLS detection unit +7, and 20 is for controlling the detection signals from each unit 15 and 17 and outputting them to the display section 20. The main control section 21 is a lotus wire that connects the detection signal from each unit 15, 17 with the main control section 20 and display section 19 for control and data exchange.

In the configuration of the C1i detection unit I5 described above, 22 is a high frequency amplification circuit that amplifies the input signal from the input terminal I6, and 23 is a resonant circuit of a capacitance element and an inductance element. An automatic tuning circuit 24 automatically tunes to the output signal frequency of the high frequency amplifier circuit 22 by continuously varying the circuit constants of both circuits at a cycle equal to or less than the duration of the incoming noise; 25 is a peak hold circuit that holds the peak value of the DC output of the detection rectifier circuit 24; 26 is a detection rectifier circuit that converts the DC output (1) of the detection rectifier circuit 24 into a reference voltage (2). 27 is a reference voltage ■. 28 is the level comparison circuit 2.
A tuned frequency detection (V-f conversion) circuit converts the output of 6 into a frequency, and outputs the halt level ~IP of the beak hole) circuit 25 only when there is an output of the comparison circuit 26. 30 is a pulse generation circuit with a constant period; 3I is a generation circuit for a tuning scan 1JEv for operating the automatic tuning circuit 23 by the pulse generated by the pulse generation circuit 30; 32 is a level comparison circuit 26;
．． Tuning frequency detection circuit 28. \AND circuit 29. This is a CW control unit that controls each output of the pulse generation circuit 30.

Next, in the configuration of the PLS detection unit 17, 33
34 is a peak hold circuit that holds the output of the preamplifier circuit 33;
35 is a level comparison circuit that compares the output level of the preamplifier circuit 33 with the reference voltage ■, 36 is a tanu variable resistance element that sets the reference voltage ■1, and 37 is only when there is an output from the level comparison circuit 35. A NAND circuit 38 sends out the output of the peak hold circuit 34, and a level comparison circuit 35. and a pulse control unit that controls each output of the NAND circuit 37.

Next, a specific example of the automatic tuning circuit 23 will be described.

FIGS. 3(a), 3(b), and 3(c) are circuit diagrams showing specific examples of the configuration. (a), (b), and (c) all show examples in which a variable capacitance element and a variable inductance element are connected in parallel.

In FIG. 3(a), 39 is a tuning coil having a winding tap, 40 is a changeover switch for the winding tap of the tuning coil 39, and 41 is a variable capacitance diode whose capacitance value changes depending on the magnitude of the applied voltage. In this example, by sequentially and repeatedly switching the winding taps of the tuning coil 39 using the changeover switch 40, the inductance can be varied continuously in a stepwise manner, and the applied voltage can be swept in a stepwise wave or a sawtooth wave. By applying a signal to the variable capacitance diode 41, its capacitance can be varied continuously. Thereby, by changing one or both of the tuning coil 39 and the variable capacitance diode 41 by electrical or mechanical means as described later, it is possible to tune to the input wave.

In FIG. 3(b), 42 is a tuning coil, 43 is a sliding switch that is slidably movable while electrically contacting the surface of the tuning coil 42, and 41 is the same as shown in the previous example. It is a movable capacitance diode. In this example, by repeatedly moving the sliding switch by mechanical means, its inductance can be varied continuously, and similarly to Fig. 3(a), a step wave or sawtooth wave sweep signal can be applied to the variable capacitance diode. 4), the capacitance can be varied continuously. With this, by varying one or both of them, it is possible to tune to the input wave.

In FIG. 3(C), 42 is a tuning coil, 44 is a core made of a magnetic material that is inserted into the winding of the tuning coil 42 and changes the inductance of the coil depending on the amount of insertion; 45
is a variable capacitor whose capacitance value is changed by mechanically changing the area where the electrodes face each other. For this example,
Tuning to the input wave is achieved by continuously changing the insertion amount of the capacitor 44 and the opposing area of the electrodes of the variable capacitor 45 by a mechanism described later.

FIG. 4 is an explanatory diagram of an embodiment for creating a tuning scan voltage v17 to be supplied as an applied voltage to a variable capacitance element such as a variable capacitance diode shown in FIGS. 3(a) and 3(b). In this example, the tuned scan voltage generation circuit 3 of FIG.
An n-ary counter circuit and a dinotal/analog conversion circuit are provided in I, and the pulse P output from the pulse generation circuit 30 is
, and convert the counted value to dinotal/analog to create a step-like repeating waveform ■,・(period 1F,)
get. In this case, the maximum count value or the frequency of the pulse P is set so that the period t1 is less than or equal to the duration of the unmonitored arrival noise. The tuning scan voltage may be shaped into a sawtooth waveform by shaping the stepped waveform (19).

FIG. 5 is a perspective view of a further embodiment of the embodiment shown in FIG. 3(c). In the configuration of this embodiment, 42 is the above-mentioned tuning coil, 44 is a core made of the above-mentioned magnetic material, and 45 is
a is a fixed electrode of the variable capacitor 45, 45b is a movable electrode of the variable capacitor 45, 46 is an eccentric cam whose radius changes with rotation, and 47 is the tip of the core 44 inserted into the coil 42 (made of non-magnetic material). 48 is a rotating shaft to which the eccentric cam 46 and the movable electrode 4.5b are fixed;
Reference numeral 9 denotes rotation driving means such as a thermomotor for rotating this rotation shaft.

With such a configuration, if the rotation drive means 49 is constantly driven with a sawtooth wave (to be described later) or a predetermined number of pulse waves (not shown), the rotation of the rotation shaft 48 will cause the movable electrode 45b and the eccentric cam 46 to move. are simultaneously rotated, the capacitance C between the movable electrode 45b and the fixed electrode 45a changes continuously, and the core 44 is moved within the coil 42 due to the eccentricity of the pressing surface of the eccentric cam 46 with respect to the tip end of the core 44. Inductance I7 changes continuously. As shown in FIG. 3(c), these variable inductances and variable capacitances jl
By forming a resonant circuit using C and inputting incoming noise to the resonant circuit, automatic tuning of the frequency to the incoming noise becomes possible.

The operation and effect of the embodiment configured as above will be described.

FIG. 6 is an explanatory diagram of the operating principle of the automatic tuning circuit 23 of FIG. 2 in this embodiment, and the tuning coil 39.4 of FIG.
Isn't the inductance of 2 variable? The tuning scan voltage Vv of a sawtooth wave shaped into a stepwise repetitive waveform as shown in FIG.
Tuning output (
b), and the tuning output (b) is frequency-converted by the V (voltage)-f (frequency) conversion characteristic (c) of the tuning frequency detection circuit 28, thereby illustrating the concept of a method for determining the tuning frequency.

Now, connect the noise detection means 13 such as the current probe shown in FIG. 1 to the input terminals 16 and 18 shown in FIG. The operation of this embodiment in the monitoring state after connecting 18 will be explained. In this state, when a short-time continuous wave, that is, a CW wave (duration 1L (1L>ts), level vx, frequency fx) as shown in FIG. 8(b) or (c) arrives on the communication line 7 side, this wave After being amplified by the high frequency amplification circuit 22 of the CW unit 15 from the input terminal 16, the output thereof is input to the automatic tuning circuit 23. On the other hand, the variable capacitance diode 41 of the automatic tuning circuit 23 is connected to the tuning scan voltage generation port N31.
Since the sawtooth-shaped tuning scan voltage v1 as shown in FIG. 6(a) created by However, the resonant frequency f, which is determined by =]/2πF, is changing.The tuned output for the input wave determined by these is the detection rectifier circuit 24.
This DC output VT is the reference level voltage V because it is constantly converted to a DC output VT.

If it becomes larger, its starting and ending voltage (
The output of the level comparison circuit 26 determined by the voltage between VL and VH, respectively, is input to the tuning frequency detection circuit 28. In the tuning frequency detection circuit 28, these voltages VL, V□
correspond to the respective frequencies f.

For example, fX−fL+(f
The frequency of the short-time continuous wave is determined as L-Lf+1)/2. On the other hand, regarding the level of such an input waveform, the peak hold circuit 25 holds only the maximum value (L), but the NAND circuit 29 operates only when there is an output from the level comparison circuit 26. and output the peak hold value.

These tuning frequency detection circuits 28. Level comparison circuit 26.
PAND circuit 29. and each output signal of the pulse generation circuit, the time 1 frequency, peak level (peak hold value) 7 times, etc. are output to the display section I9 under the control of the main control section 20 via the CW control unit 32. This information is also output to the printer. Through these operations, the level of the short-time continuous wave CW as shown in FIGS. 8(b) and 8(c) is adjusted to the set level V. If it exceeds 1, the automatic tuning circuit 23 automatically tunes it, and the noise factors such as the time 9 frequency, peak level, circuit, etc. are displayed on the display 19, and the printer also prints out the incoming noise in sequence. The above factors can be easily understood.

Regarding the automatic tuning of the short-time continuous wave CW, the inductance I of the tuning coil 39 etc. is assumed to be constant, and the capacitance variable means such as the variable capacitance diode 41 is explained using a sweep using a sawtooth wave. By changing the inductance and capacitance C simultaneously, automatic tuning over a wider frequency range becomes possible. That is, the tuning frequency f in FIG. As mentioned above, since fo = 1/2π (T), when the capacitance c is the minimum, the inductance is also the minimum, and when the capacitance @C is the most dog samurai, the inductance is also the maximum, as shown in Fig. 3 ( If it is changed by switching the switch 40 in a), sliding the sliding switch 43 in (b), inserting the core 44 in (C), fo becomes maximum when LC is minimum, and minimum when LC is maximum, and these It is clear that the range of the tuning frequency f. expands to the ratio when only the capacitance C is varied.

In this way, when detecting a short-time continuous wave (CW wave) in this embodiment, the duration of the short-time continuous wave is used as a control signal to be applied to one or both of the variable capacitance element and the variable inductance element of the automatic tuning circuit. A constant sweep is performed by using the following short-cycle sweep signal, and only when the detected and rectified DC output of the tuned output obtained by this sweep exceeds a predetermined setting level, the start and end voltages are determined. The frequency is obtained based on the frequency conversion value, and the level is obtained from the peak hold value of the DC output. These offer the advantage of easily detecting the frequency and level of short duration waves that are normally difficult to detect.

Next, when tranogent pulse noise as shown in FIG. 8(a) arrives at the monitored device 6 from the power line 9 in FIG. 1, it is detected by the noise detection means 13 coupled to the power line 9 of the monitored device 6. A signal is input to input terminal 18 in FIG. Thereby, the input signal is transmitted to the PLS detection unit 17.
The output of the peak hold circuit 34 is amplified by the preamplifier circuit 33, and the output is held by the peak hold circuit 34.Only when the output exceeds the reference setting level 2, the output of the peak hold circuit 34 is level-compared by the NAND circuit 37. The output of the circuit 35 is sent to the pulse control unit) 38t=. These signals input to the pulse control unit 1-38 are displayed on the display unit 19 with the pulse arrival time and level (peak hold value) number of times according to a command signal from the main control unit 20, and are sequentially sent to the printer. It started hitting and it hit 0.

Through these operations, when a transient pulse noise as shown in FIG. 8(a) arrives on the power line 9, if the level exceeds the set level V, it is easy to know the time, level, and number of times the noise has arrived. I can do it.

In the above embodiment, the noise detection means 13 coupled to the line serves as a means for inputting an input wave to the input terminals 16 and 18.
Although the explanation has been given using an example using the input terminal 16, it is clear that if the antenna 14 is connected to the input terminal 16 or the antenna 14, arriving waves from space as shown in FIG. 8 can also be detected. Also, a noise detection means 13 used as a means for detecting noise arriving from space such as lines such as communication lines and power lines, and antennas;
It is clear that the antenna 14 can be connected to the input terminals 16, 18 in various combinations other than the above-mentioned inversion. As described above, the present invention can be applied in various ways and can take various embodiments in accordance with the gist thereof.

``Effects of the Invention: As is clear from the above explanation, the environmental electromagnetic noise monitoring device of the present invention uses a short-time continuous wave as a control signal applied to one or both of the variable capacitance element or the variable inductance element of the resonant circuit. Since it constantly sweeps using a signal with a period shorter than the duration, and both the frequency and level are obtained based on the tuned output at this time, the detection system can be configured easily, and
It has the advantage of easily detecting the frequency and level of short-term continuous waves that are normally difficult to detect.

Furthermore, since noise factors such as the time and number (frequency) of arrival noise including transient pulses can be detected for each route, the detection level of this device can be adjusted according to the failure occurrence level of the monitored device for each route. This has the advantage of allowing you to look at the output results and easily determine the cause of the failure, such as what kind of noise arrived at a particular time and from which route.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the monitoring state of the environmental electromagnetic noise monitoring device of the present invention, FIG. 2 is a block diagram of an embodiment of the environmental electromagnetic noise monitoring device of the present invention, and FIGS. 3(a), (b), (c) is a circuit diagram showing a specific configuration example of the automatic synchronization circuit of the above embodiment, FIG. FIG. 6 is an explanatory diagram of the operating principle of the automatic synchronization circuit of the above embodiment, and FIG. 7 is a monitoring system for incoming noise of a conventional power supply noise monitoring and recording device. Connection diagram, Figure 8 (a), (b)
) and (c) are representative waveform diagrams of arriving external noise. ]... Power line (external), 6 - Monitored device, 7 Communication line, 8... Indoor rosette, 9... Power line (indoor) 10
...Noise source, II Radiated disturbance wave, 12..Environmental electromagnetic noise monitoring device, I3.-Noise detection means, I4 Antenna,
15・Short-time continuous wave (CW) detection 22)・, 16・・
Input terminal, I7...Transient pulse (PLS) detection unit, I8...Input terminal, 19 ・Display section, 20
・Main control unit, 2I bus line, 22-CW high frequency amplification circuit, 23・Automatic synchronization circuit, 24・-detection rectifier circuit, 25
Peak hold circuit, 26...Level comparison circuit, 27
Variable resistance element, 28 - Synchronous frequency detection circuit, 29
NA+'JD circuit, 30 pulse generation circuit, 31 synchronous scan voltage generation circuit, 32 CW control unit,
33 Amplification circuit, 34 ・Peak hold circuit, 35
・Level comparison circuit, 36 ・Variable resistance element, 37...
・NA, ND circuit, 38 ・Pulse control unit, 39.42... Synchronous coil, 40 Selector switch, 4
I...variable capacitance diode, 43...sliding switch,
44...Magnetic material core, 45...Variable capacitor, 45
a...Fixed electrode, 45b-variable electrode, 46-eccentric cam, 47-spring, 48-rotating shaft, 49-rotation drive means. Figure 5 Figure 1 Figure 6

Claims (1)

[Claims] (1) In an environmental electromagnetic noise monitoring device that monitors the noise intrusion path and monitors the factors of incoming noise when a failure occurs in communication equipment due to external noise, short-term continuous incoming noise that has a predetermined frequency and continues for a certain period of time and then stops. For this purpose, the circuit constants of either or both of the capacitance element and the inductance element constituting the resonant circuit are continuously variable by automatic sweeping at a cycle equal to or less than the duration of the incoming noise. Means for determining the frequency of the input wave of the incoming noise from the automatically swept voltage when the output level exceeds a predetermined set level when input, and outputting the level of the input wave together with other incoming noise factors. and means for outputting the level of the input wave together with other incoming noise factors for an input wave of transient pulsed incoming noise of a predetermined set level or higher. .