Method and apparatus for searching electromagnetic disturbing source and non-contact voltage probe apparatus therefor
First Claim
1. A method of specifying invading routes of electromagnetic interference, comprising the steps of:
- measuring voltages and currents of the electromagnetic interference developed in each of a plurality of cables electrically connected to pieces of electronic equipment by voltage and current probes, respectively;
calculating an effective component of energy of the electromagnetic interference in each of said cables from the result of said measurements; and
specifying an invading route of the electromagnetic interference from a direction in which a calculated energy flows.
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Abstract
Voltages and currents of electromagnetic interference developed in cables or the like electrically connected to pieces of electronic equipment are respectively measured by non-contact voltage probes and non-contact current probes both of which have double coaxial cylindrical type inner and outer electrodes and wherein the outer electrode is grounded and a voltage output under capacitive coupling is taken out from the inner electrode. An effective component of energy of each propagating electromagnetic interference is calculated from the result of the measurements. An invading route of each electromagnetic interference is specified from the magnitude of the energy and the direction in which the energy flows. While the pieces of electronic equipment are being placed under operating conditions, the behavior of the electromagnetic interference can be accurately recognized and the invading route of each electromagnetic interference can be quantitatively specified according to a physical quantity.
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Citations
29 Claims
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1. A method of specifying invading routes of electromagnetic interference, comprising the steps of:
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measuring voltages and currents of the electromagnetic interference developed in each of a plurality of cables electrically connected to pieces of electronic equipment by voltage and current probes, respectively; calculating an effective component of energy of the electromagnetic interference in each of said cables from the result of said measurements; and specifying an invading route of the electromagnetic interference from a direction in which a calculated energy flows. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An apparatus for searching for an electromagnetic interference source, comprising:
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a plurality of non-contact voltage probes respectively connected in non-contact relationships with a plurality of cables connected to pieces of electronic equipment; a plurality of non-contact current probes respectively connected in non-contact relationships with the plurality of cables; means for inputting therein a voltage and a current of the electromagnetic interference source both measured by voltage and current probes connected to the same cable of said plurality of cables and calculating an effective component of energy of each electromagnetic interference source; and means for specifying an invading route of each electromagnetic interference source from a direction in which a calculated energy flows. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. An apparatus for searching for an electromagnetic interference source, comprising:
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means for measuring, in a time domain, waveforms of a voltage v(t) and a current i(t) of the electromagnetic interference source developed in each of cables connected to electronic equipment; means for recording measured waveforms of voltage and current therein; means for converting the measured waveforms of voltage and current into waveforms of a voltage and a current in a frequency domain respectively; means for calculating energy for each frequency, based on the voltage and current waveforms in the frequency domain; and means for displaying the calculated energy for each frequency in the form of positive and negative polarities of the energy and a magnitude thereof so as to correspond to coordinates indicative of each frequency. - View Dependent Claims (26, 27, 28, 29)
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Specification