Patent No. 6411104 Apparatus and method for detecting electromagnetic wave source, and method for analyzing the same
Patent No. 6411104
Apparatus and method for detecting electromagnetic wave source, and method for analyzing the same (Uesaka, et al., Jun 25, 2002)
Abstract
There are provided electromagnetic wave source detecting apparatus and method as well as electromagnetic wave source analyzing system and method which can detect and analyze a source of (electromagnetic disturbing wave) representing a main factor in generating an electromagnetic field remotely of the apparatus in order to suppress the electromagnetic field intensity at the remote distance from the apparatus to below a regulated value. In the present invention, a magnetic field near an object 110 to be measured is measured by a set of at least two or more probes 101 and 102, a position of an electromagnetic wave source is detected through simplified calculation of one function using a phase difference between the two probes, a current distribution on the measured object is determined by solving simultaneous equations containing the position information and magnitudes of measured magnetic fields and an electromagnetic field at a remote distance from the apparatus is determined from the current distribution, thereby identifying the source representing the main factor in generating the electromagnetic field remotely of the apparatus.
Notes:
Apparatus
and method for detecting electromagnetic wave source, and method for analyzing
the same. Filed April 2000, granted June 2002. Device for detecting an electromagnetic
wave, measuring its intensity and using a triangulation method for determining
where said electromagnetic wave is emanating from. Larger scale for psychotronic
attacks maybe. As is would be useful for detecting attacks on electronic equipment
in home or office by electromagnetic weaponry.
SUMMARY
OF THE INVENTION
To accomplish the above objects, an electromagnetic wave source detecting apparatus
according to the invention comprises a plurality of probes for measuring intensities
Hm (inclusive of phase data) of an electromagnetic field generated from an object
to be measured of an electronic apparatus at each measuring position (x.sub.m,
y.sub.m) which changes two-dimensionally along a measured object plane near
the measured object, and calculation means for calculating a phase difference
.DELTA..phi..sub.m =(.phi..sub.2 -.phi..sub.1).sub.m or time difference .DELTA.t.sub.m
=(t.sub.2 -t.sub.1).sub.m between magnetic fields associated with the probes
from the electromagnetic field intensities Hm measured by the individual plural
probes at each measuring position (x.sub.m, y.sub.m), calculating a difference
d between distances from a presumptive electromagnetic wave source on the basis
of the phase difference or time difference calculated at each measuring position,
determining a locus of the presumptive electromagnetic wave source on the measured
object plane from the distance difference d and geometrical relations (for example,
z.sub.1, z.sub.2) of the plurality of probes to the measured object and detecting
an intersection of loci of the presumptive electromagnetic wave source which
are determined at a plurality of measuring positions to calculate and identify
a position (x.sub.s, y.sub.s).sub.n of an electromagnetic wave source existing
in the measured object.
Further, an electromagnetic wave source detecting apparatus according to the
invention comprises a plurality of probes for measuring intensities Hm (inclusive
of phase data) of an electromagnetic field generated from an object to be measured
of an electronic apparatus at each measuring position (x.sub.m, y.sub.m) which
changes two-dimensionally along a measured object plane near the measured object,
and calculation means for calculating a phase difference .DELTA..phi..sub.m
=(.phi..sub.2 -.phi..sub.1).sub.m or time difference .DELTA.t.sub.m =(t.sub.2
-t.sub.1).sub.m between magnetic fields associated with the probes from the
electromagnetic field intensities Hm measured by the individual plural probes
at each measuring position (x.sub.m, y.sub.m), calculating a difference d between
distances from a presumptive electromagnetic wave source on the basis of the
phase difference or time difference calculated at each measuring position, determining
a locus of the presumptive electromagnetic wave source on the measured object
plane from the distance difference d and geometric relations (for example, z.sub.1,
z.sub.2) of the plurality of probes to the measured object, detecting an intersection
(x.sub.s, y.sub.s).sub.n of loci of the presumptive electromagnetic wave source
which are determined at a plurality of measuring positions to calculate and
identify a position of an electromagnetic wave source existing inside the measured
object, and further calculating magnitude In of current in the electromagnetic
wave source existing at the identified position on the basis of the electromagnetic
field intensities Hm measured by the probes at each measuring position.
Further, an electromagnetic wave source detecting apparatus according to the
invention comprises a plurality of probes for measuring intensities Hm of an
electromagnetic field generated from an object to be measured of an electronic
apparatus at each measuring position (x.sub.m, y.sub.m) which changes two-dimensionally
along a measured object plane near the measured object, and calculation means
for calculating a phase difference .DELTA..phi..sub.m =(.phi..sub.2 -.phi..sub.1).sub.m
or time difference .DELTA.t.sub.m =(t.sub.2 -t.sub.1).sub.m between magnetic
fields associated with the probes from the electromagnetic field intensities
Hm measured by the individual plural probes at each measuring position, calculating
a difference d between distances from a presumptive electromagnetic wave source
on the basis of the phase difference or time difference calculated at each measuring
position, determining a locus of the presumptive electromagnetic wave source
on the measured object plane from the distance difference d and geometrical
relations (for example, z.sub.1, z.sub.2) of the plurality of probes to the
measured object, detecting an intersection (x.sub.s, y.sub.s).sub.n of loci
of the presumptive electromagnetic wave source which are determined at a plurality
of measuring positions to calculate and identify a position of an electromagnetic
wave source existing inside the measured object, and further calculating magnitudes
In of current distributions in a plurality of electromagnetic wave sources existing
at individual plural positions identified similarly on the basis of the electromagnetic
field intensities Hm measured by the probes at each measuring position.
Further, in the present invention, the plurality of probes in the electromagnetic
wave source detecting apparatus are arranged on the same probe axis at the individual
measuring positions.
Further, in the present invention, the plurality of probes in the electromagnetic
wave source detecting apparatus are arranged on the same probe axis vertical
to the measured object plane at the individual measuring positions (x.sub.m,
y.sub.m). In this case, the locus of the presumptive electromagnetic wave source
on the measured object plane is indicated by a radius a.sub.m.
Further, in the present invention, the calculation means of the electromagnetic
wave source detecting apparatus further calculates inversely an electromagnetic
field intensity En at a desired remote distance on the basis of the calculated
magnitude of a current distribution in the electromagnetic wave source existing
at the identified position on the measured object.
Further, in the present invention, the calculation means of the electromagnetic
wave source detecting apparats inversely calculates an electromagnetic field
intensity En at a desired remote distance on the basis of the calculated magnitude
of a current distribution in each of the plurality of electromagnetic wave sources
existing at each of the identified plural positions on the measured object.
Further, an electromagnetic wave source analyzing method according to the invention
collates a position of an electromagnetic wave source existing on a measured
object identified by using the aforementioned electromagnetic wave source detecting
apparatus with mounting information (for example, circuit diagrams or mounting
diagrams) of the measured object through, for example, display on a display
unit. This permits electronic parts generating an unwanted electromagnetic wave
(electromagnetic disturbing wave) to be ascertained.
Further, an electromagnetic wave source analyzing method according to the invention
analyzes whether an electromagnetic field intensity at a desired remote distance
calculated by using the electromagnetic wave source detecting apparatus satisfies
the VCCI standards.
Further, an electromagnetic wave source detecting method according to the invention
comprises measuring intensities Hm of an electromagnetic field generated from
an object to be measured of an electronic apparatus at each measuring position
(x.sub.m, y.sub.m) which changes two-dimensionally along a measured object plane
near the measured object by using a plurality of probes, calculating a phase
difference .DELTA..phi..sub.m =(.phi..sub.2 -.phi..sub.1).sub.m or time difference
.DELTA.t.sub.m =(t.sub.2 -t.sub.1).sub.m between magnetic fields associated
with the probes from the magnetic field intensities Hm measured at each measuring
position (x.sub.m, y.sub.m), calculating a difference d between distances from
a presumptive electromagnetic wave-source on the basis of the phase difference
or time difference calculated at each measuring position, determining a locus
of the presumptive electromagnetic wave source on the measured object plane
from the distance difference d and geometrical relations (for example, z.sub.1,
z.sub.2) of the plurality of probes to the measured object, and detecting an
intersection (x.sub.s, y.sub.s).sub.n of loci of the presumptive electromagnetic
wave source which are determined at a plurality of measuring positions to calculate
and identify a position of an electromagnetic wave source existing inside the
measured object.
Further, an electromagnetic wave source detecting method according to the invention
comprises measuring intensities Hm of an electromagnetic field generated from
an object to be measured of an electronic apparatus at each measuring position
(x.sub.m, y.sub.m) which changes two-dimensionally along a measured object plane
near the measured object by using a plurality of probes, calculating a phase
difference .DELTA..phi..sub.m =(.phi..sub.2 -.phi..sub.1).sub.m or time difference
.DELTA.t.sub.m =(t.sub.2 -t.sub.1).sub.m between magnetic fields associated
with the probes from the electromagnetic field intensities Hm measured at each
measuring position, calculating a difference d between distances from a presumptive
electromagnetic wave source on the basis of the phase difference or time difference
calculated at each measuring position, determining a locus of the presumptive
electromagnetic wave source on the measured object plane from the distance difference
d and geometrical relations (for example, z.sub.1, z.sub.2) of the plurality
of probes to the measured object, detecting an intersection (x.sub.s, y.sub.s).sub.n
of loci of the presumptive electromagnetic wave source which are determined
at a plurality of measuring positions to calculate and identify an electromagnetic
wave source existing inside the measured object, and further calculating magnitude
In of current in the electromagnetic wave source existing at the identified
position on the basis of the electromagnetic field intensities measured by the
probes at each measuring position.
As described above, with the construction as above, by approaching only magnetic
field probes small enough not to disturb magnetic fields from the main body
of the measuring apparatus to the measured object, the positions of electromagnetic
wave sources existing at arbitrary positions on the measured object can be presumed
from the phase information by reducing the number M of measuring points of magnetic
field distribution without being affected by the influence of reflection to
obtain the number N (=M) of the sources, thereby ensuring that the positions
of the electromagnetic wave sources existing at the arbitrary positions can
be presumed with high accuracy and at a high rate.
Further, with the above construction, it can be analyzed and decided whether
the measured object satisfies the VCCI standards.
Further, with the above construction, factors (kinds of electronic parts) of
the source of unwanted electromagnetic wave (electromagnetic disturbing wave)
detected on the measured object can be surveyed.
Comments