For measuring method and the magnet field probe of magnetic field radiationTechnical field
The present invention relates near field measurement field, particularly relating to a kind of method for measuring magnetic field radiation and magnet field probe.
Background technology
Electromagnetic interference (EMI) size general antenna carries out far-field measurement, but whether the electromagnetic interference (EMI) size that the test result in far field can only measure product exceedes limit value, can not measure electromagnetic radiation is the gap coming from housing, or from the cable connected, or the communication interface of USB, LAN and so on, in this case, the real source of electromagnetic radiation can be determined by the method for near field measurement.
Usually, wiring on the pin of chip, device, PCB, power lead and signal cable etc. all can produce magnetic field radiation, magnet field probe can provide a signal be directly proportional to the intensity of this magnetic field radiation, measured by magnet field probe and just can measure the size of magnetic field radiation in conjunction with spectrum analyzer, thus knowing that there is magnetic field radiation problem product which position concrete.
Conventional magnet field probe mostly is monocycle shape, when magnetic field line of propagation is vertical with probe anchor ring time, measures numerical value maximum, therefore, in measuring process, slip-stick artist generally needs the direction of rotating detector to measure maximum field value, avoids omitting important emissive source simultaneously.Owing to only there being an annular probe, need to rotate at same position just to measure maximum magnetic field radiation position, this has just had a strong impact on testing efficiency.
For the problems referred to above existing in prior art, provide a kind of having great importance for the method and magnet field probe measuring magnetic field radiation newly.
Summary of the invention
For solving the problem, the invention provides a kind of method for measuring magnetic field radiation and magnet field probe, it can improve the efficiency determining that magnetic field radiation is originated.
For achieving the above object, the method for measuring magnetic field radiation of the present invention, comprising: the plane be fixedly installed by three coils as these three coils place is separately orthogonal between two, and described coil comprises external shielding layer and inner core; The two ends of the described inner core of three coils are connected in parallel to the interface of spectrum analyzer, are sent to spectrum analyzer with the electric current sensed from magnetic field radiation by least one coil in three coils; Spectrum analyzer according to from described interface to the size of magnetic field intensity of current sensor determination coil position.
Preferably, spectrum analyzer by by from described interface to current sensor be converted to the size that voltage determines described magnetic field intensity.
Preferably, described coil is circular or rectangular ring.
Preferably, described external shielding layer is copper shield.
The invention also discloses a kind of magnet field probe for measuring magnetic field radiation, it comprises plane mutually perpendicular coil and the handle for fixed support three described coils between two that three are set to its place separately, described coil comprises external shielding layer and inner core, the two ends of described inner core from one end of described handle through described handle and be connected to the other end outside being formed in described handle joint, or the two ends of described inner core form described joint from one end of handle through the other end outside at described handle after described handle, described joint is used for being connected with the interface of spectrum analyzer.
Preferably, described handle comprises the handle screen layer be connected with described external shielding layer.
Preferably, described coil is circular or rectangular ring.
Preferably, described external shielding layer and described handle screen layer are copper shield.
Method for measuring magnetic field radiation of the present invention and magnet field probe, measure by arranging the magnetic field radiation of three mutually perpendicular coils to each position of product, the magnitude of field intensity that this probe gets final product each position of Quick Measurement product need not be rotated, thus determine the source of magnetic field radiation.This magnet field probe structure is simple, easy to use.
Accompanying drawing explanation
Fig. 1 is of the present invention for determining that schematic diagram arranged by the coil in the method that magnetic field radiation is originated;
Fig. 2 is the schematic diagram of intermediate frequency spectrum analyser of the present invention;
Fig. 3 is the structural representation of the magnet field probe for measuring magnetic field radiation of the present invention.
Embodiment
Below, by reference to the accompanying drawings, structure of the present invention and principle of work etc. are further described.
See Fig. 1, Fig. 2, method for measuring magnetic field radiation of the present invention, comprise: being fixedly installed by three coils 1 is that the plane at three coils place is separately orthogonal between two, as shown in Figure 1, in three planes that the x, y, z axle that three coils 1 are fixedly installed on three-dimensional system of coordinate respectively limits between two, coil 1 comprises external shielding layer 101 and inner core 102.
When needing the source of magnetic field radiation of measurement products, the two ends of the inner core 102 of three coils are connected in parallel to the interface of spectrum analyzer 3.As shown in Figure 2, signal input interface one end of spectrum analyzer 3 is earth terminal 301, and the other end is signal incoming end 302.Respectively one end of three inner cores 102 is connected earth terminal 301, other end connection signal incoming end 302 can be measured.By each detected part of product close for three coils be fixedly installed, according to the magnetic field radiation at coil position place, based on Hall effect, each coil transduces is to phase induced current and be sent to the signal incoming end 302 of spectrum analyzer.Because three coils from parallel connection of coils are connected to the interface of spectrum analyzer, therefore each coil transduces to electric current the parallel connection of signal incoming end 302 place obtain with product survey total current sensor corresponding to the magnetic field radiation at position, subsequently spectrum analyzer according to from interface to total current sensor determination product survey the size of the radiant magnetic-field intensity at position and the screen being presented on spectrum analyzer checked for user.By the size distribution situation of the radiant magnetic-field intensity at each position of analytic product, can determine that product which position concrete exists magnetic field radiation problem.
The measurement situation that below explanation two kinds is special.When the magnetic direction at the anchor ring just in time position tested with product of the coil of in three coils is vertical, and when the anchor ring of another two coils is all parallel to magnetic direction, only has this coil transduces vertical with magnetic direction to electric current and be sent to spectrum analyzer.In addition, when the magnetic direction at the anchor ring just in time position tested with product of the coil of in three coils is parallel, and when the anchor ring of another two coils is all not parallel with magnetic direction, only has these not parallel with magnetic direction two coil transduces to electric current and be all sent to spectrum analyzer.That is, in any case at least have a coil transduces in three coils to electric current, and spectrum analyzer according to the current sensor received can determine product survey the size of the radiant magnetic-field intensity at position.
Spectrum analyzer determines the magnitude of field intensity at surveyed position by the size directly measuring above-mentioned total current sensor, also can be converted to from the total current sensor received the size that voltage determines described magnetic field intensity by set internal resistance.
The shape of coil 1 can have multiple choices, and as shown in Figure 1, the shape of coil 1 can be straight-flanked ring; Certainly, the shape of coil 1 can also in the toroidal as circular magnetic field probe head of the prior art.
External shielding layer 101 can be copper shield, but is not limited thereto.
See Fig. 3, the magnet field probe for measuring magnetic field radiation of the present invention comprises screen mutually perpendicular coil 1 and the handle 2 for fixed support three coils 1 between two that three are set to its place separately, and coil 1 comprises external shielding layer 101 and inner core 102.Handle 2 is in hollow form, and it comprises the handle screen layer 201 be connected with the external shielding layer 101 of coil 1.The two ends of the inner core 102 of three coils 1 are passed handle 2 inside from one end of handle 2 and are connected to the joint being formed in handle 2 other end outside, or the two ends of each inner core 102 form joint from one end of handle 2 through the other end outside at handle 2 after handle 2, this joint is used for being connected with the interface of spectrum analyzer 3, each one end of inner core 102 is connected with the signal incoming end 302 of the interface of spectrum analyzer, and the other end of inner core 102 is connected with the earth terminal 301 of the interface of spectrum analyzer.Thus, spectrum analyzer can according to from its interface to the total current sensor determination product from coil survey the size of the magnetic field intensity at position and the screen being presented on spectrum analyzer checked for user.By the size distribution situation of the radiant magnetic-field intensity at each position of analytic product, can determine that product which position concrete exists magnetic field radiation problem.
By the magnet field probe of this spline structure, as long as be placed in magnetic field radiation, in any case at least have a coil transduces in three coils to electric current, and spectrum analyzer according to the current sensor received can determine product survey the size of the radiant magnetic-field intensity at position.User need not adjust the direction of magnet field probe continually, drastically increases the efficiency measuring magnetic field radiation.
Certainly, the structure of coil 1 can also be realized by other various structures, the structure of the coil in existing magnet field probe can be selected, such as, can be chosen as structure that notification number is coil in the utility model patent of CN204331002U and notification number is structure of coil in the utility model patent of CN203572948U etc.
As finished product, the shape of coil 1 can have multiple choices, and as shown in Figure 3, coil 1 can in circular; The all right rectangular ring-type of coil 1, as shown in Figure 1.
External shielding layer 101 and handle screen layer 201 can be copper shield, but are not limited thereto.
Above, be only schematic description of the present invention, it will be recognized by those skilled in the art that on the basis of not departing from principle of work of the present invention, can make multiple improvement to the present invention, this all belongs to protection scope of the present invention.