ʻO nā mea hana maʻamau no ka hoʻopauʻana PCB include: time domain oscilloscope, TDR (time domain reflectometry) oscilloscope, logic analyzer, and frequency domain spectrum analyzer and other equipment, but these methods can not give a reflection of the overall information of the PCB board. data. PCB board is also called printed circuit board, printed circuit board, printed circuit board for short, PCB (printed circuit board) or PWB (printed wiring board) for short, using insulating board as the base material, cut into a certain size, and at least attached A conductive pattern with holes (such as component holes, fastening holes, metallized holes, etc.) is used to replace the chassis of the electronic components of the previous device and realize the interconnection between the electronic components. Because this board is made using electronic printing, it is called a “printed” circuit board. It is not accurate to call “printed circuit board” as “printed circuit” because there are no “printed components” but only wiring on the printed circuit board.

Pehea e loaʻa ai a hoʻopili i ka ʻike electromagnetic PCB

Hoʻohana ka Emscan electromagnetic compatibility scanning system i kahi ʻenehana antenna patented array a me ka ʻenehana hoʻololi uila, hiki ke ana i ke ʻano o ka PCB i ka wikiwiki kiʻekiʻe. ʻO ke kī iā Emscan ʻo ia ka hoʻohana ʻana i kahi antenna array patented e ana i ka radiation kokoke kokoke i ka PCB hana i kau ʻia ma ka scanner. He 40 x 32 (1280) liʻiliʻi kēia ʻano antenna, i hoʻokomo ʻia i loko o kahi papa kaapuni 8-layer, a ua hoʻohui ʻia kahi papa pale i ka papa kaapuni e hoʻāʻo ai i ka PCB. Hiki i nā hopena o ka nānā ʻana ke kikoo ke hāʻawi iā mākou i ka ʻike paʻakikī o ka spectrum i hana ʻia e ka EUT: ehia mau ʻāpana alapine, a me ka nui o kēlā me kēia ʻāpana alapine.

Hoʻopaʻa paʻa piha

The design of the PCB board is based on the circuit schematic diagram to realize the functions required by the circuit designer. The design of the printed circuit board mainly refers to the layout design, which needs to consider various factors such as the layout of external connections, the optimized layout of internal electronic components, the optimized layout of metal connections and through holes, electromagnetic protection, and heat dissipation. Excellent layout design can save production cost and achieve good circuit performance and heat dissipation performance. Simple layout design can be realized by hand, while complex layout design needs to be realized with the aid of computer-aided design.

Ke hoʻokō nei i ka hana kikoʻī/spatial scanning, kau i ka PCB hana ma ka scanner. Hoʻokaʻawale ʻia ka PCB i 7.6mm × 7.6mm grids e ka mākia o ka scanner (ʻo kēlā me kēia pahu he H-field probe), a hoʻokō Ma hope o ka nānā ʻana i ka pahu alapine piha o kēlā me kēia probe (hiki ke alapine mai 10kHz-3GHz) , Hāʻawi hope ʻo Emscan i ʻelua kiʻi, ʻo ia hoʻi ka spectrogram synthesized (Figure 1) a me ka palapala ‘āina synthesized (Figure 2).

Pehea e loaʻa ai a hoʻopili i ka ʻike electromagnetic PCB

Spectrum/spatial scanning obtains all the spectrum data of each probe in the entire scanning area. After performing a spectrum/spatial scan, you can get the electromagnetic radiation information of all frequencies at all spatial locations. You can imagine the spectrum/spatial scan data in Figure 1 and Figure 2 as a bunch of spatial scan data or a bunch of spectrum Scan the data. you can:

1. E nānā i ka palapala ʻāina māhele ʻāina o ke kiko alapine i ʻōlelo ʻia (hoʻokahi a ʻoi aku paha nā alapine) e like me ka nānā ʻana i ka hopena scan spatial, e like me ka hōʻike ʻana ma ke Kiʻi 3.

2. Nānā i ka spectrogram o ke kiko kiko kiko (hoʻokahi a ʻoi aku paha nā mākia) e like me ka nānā ʻana i ka hopena scan spectrum.

ʻO nā kiʻi hoʻohele like ʻole ma ke kiʻi. Loaʻa ia ma ka wehewehe ʻana i ke kiko alapine me × ma ka spectrogram kiʻekiʻe loa ma ke kiʻi. Hiki iā ʻoe ke kuhikuhi i kahi helu alapine (frequency point) e nānā i ka puʻunaue spatial o kēlā me kēia alapine (frequency point), a i ʻole hiki iā ʻoe ke kuhikuhi i nā helu alapine he nui, no ka laʻana, e kuhikuhi i nā wahi harmonic āpau o 3M e nānā i ka huina spectrogram.

In the spectrogram in Figure 4, the gray part is the total spectrogram, and the blue part is the spectrogram at the specified position. By specifying the physical location on the PCB with ×, comparing the spectrogram (blue) and the total spectrogram (gray) generated at that position, the location of the interference source is found. It can be seen from Figure 4 that this method can quickly find the location of the interference source for both broadband interference and narrowband interference.

E ʻimi koke i ke kumu o ka hoʻopilikia electromagnetic

Pehea e loaʻa ai a hoʻopili i ka ʻike electromagnetic PCB

A spectrum analyzer is an instrument for studying the spectrum structure of electrical signals. It is used to measure signal distortion, modulation, spectral purity, frequency stability, and intermodulation distortion. It can be used to measure certain circuit systems such as amplifiers and filters. Parameter is a multi-purpose electronic measuring instrument. It can also be called frequency domain oscilloscope, tracking oscilloscope, analysis oscilloscope, harmonic analyzer, frequency characteristic analyzer or Fourier analyzer. Modern spectrum analyzers can display analysis results in analog or digital ways, and can analyze electrical signals in all radio frequency bands from very low frequency to sub-millimeter wave bands below 1 Hz.

Hiki i ka hoʻohana ʻana i kahi loiloi spectrum a me kahi ʻimi hoʻokahi kokoke i ke kahua hiki ke ʻimi i “nā kumu hoʻopilikia”. Maʻaneʻi mākou e hoʻohana i keʻano o ka “hoʻopau i ke ahi” ma keʻano he metaphor. Hiki ke hoʻohālikelike ʻia ka hoʻokolohua mamao loa (EMC standard test) me ka “ʻike i ke ahi”. Inā ʻoi aʻe ka helu alapine i ka waiwai palena, manaʻo ʻia ʻo ia “ua loaʻa ke ahi.” Hoʻohana mau ʻia ka hopena “spectrum analyzer + single probe” e nā ʻenekini EMI e ʻike “mai kahi ʻāpana o ka chassis e puka mai ai ka lapalapa”. Ma hope o ka ʻike ʻia ʻana o ka lapalapa, ʻo ke ʻano hana hoʻopau EMI maʻamau e hoʻohana i ka pale a me ka kānana. Ua uhi ʻia ʻo “Flame” i loko o ka huahana. ʻAe ʻo Emscan iā mākou e ʻike i ke kumu o ke kumu keakea- “ahi”, akā e ʻike pū i ke “ahi”, ʻo ia hoʻi, ke ala e laha ai ke kumu hoʻopilikia.

Hiki ke ʻike maopopo ʻia ʻo ka hoʻohana ʻana i ka “ʻike electromagnetic piha”, ʻoi aku ka maʻalahi o ka ʻimi ʻana i nā kumu hoʻopilikia electromagnetic, ʻaʻole hiki ke hoʻonā i ka pilikia o ka narrowband electromagnetic interference, akā maikaʻi hoʻi no ka broadband electromagnetic interference.

ʻO ke ʻano hana maʻamau penei:

Pehea e loaʻa ai a hoʻopili i ka ʻike electromagnetic PCB

(1) E nānā i ka puunaue spatial o ka nalu kumu, a e huli i ke kūlana kino me ka amplitude nui loa ma ka palapala ‘āina mahele o ka nalu kumu. No ka hoʻopili ʻana i ka broadband, e hōʻike i kahi alapine ma waena o ke alapine broadband (e like me ka 60MHz-80MHz broadband interference, hiki iā mākou ke kuhikuhi i ka 70MHz), e nānā i ka puʻuna spatial o ke kiko alapine, a ʻimi i ka wahi kino me ka amplitude nui loa.

(2) Specify the location and look at the spectrogram of the location. Check whether the amplitude of each harmonic point at this position coincides with the total spectrogram. If they overlap, it means that the designated location is the strongest place that produces these interferences. For broadband interference, check whether the location is the maximum location of the entire broadband interference.

(3) In many cases, not all harmonics are generated at one location. Sometimes even harmonics and odd harmonics are generated at different locations, or each harmonic component may be generated at different locations. In this case, you can find the location with the strongest radiation by looking at the spatial distribution of the frequency points you care about.

(4) ʻO ka hana ʻana i nā wahi me ka pāhawewe ikaika loa, ʻo ia ka hopena maikaʻi loa i nā pilikia EMI/EMC.

ʻO kēia ʻano hana noiʻi EMI hiki ke ʻimi maoli i ke “kumu” a me ke ala hoʻolaha e hiki ai i nā ʻenekinia ke hoʻopau i nā pilikia EMI ma ke kumu kūʻai haʻahaʻa a me ka wikiwiki loa. Ma kahi hihia ana maoli o kahi mea kamaʻilio, hoʻoheheʻe ʻia mai ke kaula laina kelepona. Ma hope o ka hoʻohana ʻana iā EMSCAN no ka hoʻokō ʻana i ka nānā ʻana a me ka nānā ʻana i ʻōlelo ʻia ma luna, ua hoʻokomo ʻia kekahi mau capacitor kānana hou aʻe ma ka papa hana, kahi i hoʻoponopono ai i ka pilikia EMI i hiki ʻole i ka ʻenekini ke hoʻoponopono.

Quickly locate the circuit fault location

Pehea e loaʻa ai a hoʻopili i ka ʻike electromagnetic PCB

Me ka piʻi ʻana o ka paʻakikī PCB, ke hoʻonui nei ka paʻakikī a me ka hana o ka debugging. Me ka oscilloscope a i ʻole ka loiloi loiloi, hiki ke ʻike ʻia hoʻokahi a i ʻole ka helu palena o nā laina hōʻailona i ka manawa like. Eia naʻe, aia paha he mau kaukani laina hōʻailona ma ka PCB. Hiki i nā ʻenekinia ke loaʻa ka pilikia ma o ka ʻike a i ʻole ka laki. ʻO ka pilikia.

Inā loaʻa iā mākou ka “ʻike electromagnetic piha” o ka papa maʻamau a me ka papa hewa, hiki iā mākou ke hoʻohālikelike i ka ʻikepili o nā mea ʻelua e ʻike ai i ke alapine alapine maʻamau, a laila hoʻohana i ka “interference source location technology” e ʻike i kahi o ka ʻano alapine ʻokoʻa. E huli i kahi a me ke kumu o ka hemahema.

Hōʻike ke kiʻi 5 i ke alapine alapine o ka papa maʻamau a me ka papa hewa. Ma o ka hoʻohālikelike ʻana, maʻalahi ka ʻike ʻana aia kahi hoʻopiʻi ākea ākea ma ka papa hewa.

A laila, e huli i ka wahi i hana ʻia ai kēia “ʻano alapine kūpono ʻole” ma ka palapala hoʻohele ākea o ka papa hewa, e like me ka hōʻike ʻana ma ke Kiʻi 6. Ma kēia ʻano, aia ka wahi hewa ma kahi pā (7.6mm×7.6mm), a hiki ke pilikia loa ka pilikia. E hana koke ʻia ka ʻike.

Pehea e loaʻa ai a hoʻopili i ka ʻike electromagnetic PCB

Nā hihia noi no ka loiloi ʻana i ka maikaʻi o ka hoʻolālā PCB

A good PCB needs to be carefully designed by an engineer. The issues that need to be considered include:

(1) Hoʻolālā cascading kūpono

ʻOi aku ka maikaʻi o ka hoʻonohonoho ʻana o ka mokulele honua a me ka mokulele mana, a me ka hoʻolālā ʻana o ka papa kahi i loaʻa ai nā laina hōʻailona koʻikoʻi a me nā laina hōʻailona e hoʻoulu ai i ka nui o ka radiation. Aia kekahi mahele o ka mokulele honua a me ka mokulele mana, a me ka hoʻokele ʻana o nā laina hōʻailona ma kēlā ʻaoʻao o ka wahi i māhele ʻia.

(2) E mālama i ka impedance laina hōʻailona e like me ka hiki

E like me ka liʻiliʻi o nā vias; kakaikahi me ka huina kupono; a me ka liʻiliʻi e like me ka hiki ke hoʻihoʻi i kēia manawa, hiki iā ia ke hana i nā harmonics liʻiliʻi a me ka haʻahaʻa haʻahaʻa haʻahaʻa.

(3) He kānana mana maikaʻi

ʻO ke ʻano capacitor kānana kūpono, ka waiwai capacitance, ka nui, a me ke kūlana hoʻonohonoho, a me kahi hoʻonohonoho papa kūpono o ka mokulele honua a me ka mokulele mana, hiki ke hōʻoia i ka hoʻokele electromagnetic interference ma kahi liʻiliʻi loa.

(4) E ho’āʻo e hōʻoia i ka pono o ka mokulele honua

Pehea e loaʻa ai a hoʻopili i ka ʻike electromagnetic PCB

E like me ka liʻiliʻi o nā vias; kūpono ma o ka palekana palekana; hoʻonohonoho pono o ka mea hana; kūpono ma o ka hoʻonohonoho ʻana e hōʻoia i ka pono o ka mokulele honua i ka nui loa. ʻO ka mea ʻē aʻe, ʻo nā vias paʻa a nui loa ma o ka spacing palekana, a i ʻole ka hoʻonohonoho ʻana o nā mea hana pono ʻole, e hoʻopilikia nui i ka pono o ka mokulele honua a me ka mokulele mana, e hopena i ka nui o ka crosstalk inductive, radiation mode maʻamau. paʻakikī i ke keakea o waho.

(5) E ʻimi i kahi kuʻikahi ma waena o ka hōʻailona pono a me ka hoʻohālikelike electromagnetic

Ma ke kumu o ka hōʻoia ʻana i ka hana maʻamau o nā mea hana, e hoʻonui i ka piʻi ʻana a me ka hāʻule ʻana o ka manawa o ka hōʻailona e like me ka hiki ke hōʻemi i ka amplitude a me ka helu o nā harmonics o ka radiation electromagnetic i hana ʻia e ka hōʻailona. No ka laʻana, pono ʻoe e koho i kahi resistor damping kūpono, kahi ala kānana kūpono, a pēlā aku.

I ka wā ma mua, hiki i ka hoʻohana ʻana i ka ʻike kahua electromagnetic piha i hana ʻia e ka PCB hiki ke loiloi ʻepekema i ka maikaʻi o ka hoʻolālā PCB. Ke hoʻohana nei i ka ʻike electromagnetic piha o ka PCB, hiki ke loiloi ʻia ka maikaʻi o ka hoʻolālā ʻana o ka PCB mai nā ʻano ʻehā: 1. ʻO ka helu o nā helu alapine: ka helu o nā harmonics. 2. Hoʻopiʻi kūwaho: hoʻopili electromagnetic paʻa ʻole. 3. ʻO ka ikaika o ka radiation: ka nui o ka hoʻopili electromagnetic i kēlā me kēia alapine. 4. Wahi mahele: ka nui o ka mahele o ka hoʻopili electromagnetic i kēlā me kēia alapine ma ka PCB.

Ma kēia laʻana, ʻo ka papa A kahi hoʻomaikaʻi o ka papa B. ʻO nā kiʻi hoʻolālā o nā papaʻelua a me ka hoʻonohonohoʻana o nā mea nui e like loa. Hōʻike ʻia nā hopena o ka spectrum/spatial scanning o nā papa ʻelua ma ke Kiʻi 7:

Mai ka spectrogram ma ke Kiʻi 7, hiki ke ʻike ʻia ʻoi aku ka maikaʻi o ka papa A ma mua o ka papa B, no ka mea:

1. Ua emi iho ka helu o na kiko alapine o ka papa A ma mua o ko ka papa B;

2. ‘Oi aku ka li’ili’i o ka nui o na kiko alapine o ka papa A ma mua o ko ka papa B;

3. The transient interference (frequency points that are not marked) of the A board is less than that of the B board.

Pehea e loaʻa ai a hoʻopili i ka ʻike electromagnetic PCB

Hiki ke ʻike ʻia mai ke kiʻikuhi ākea ka ʻoi aku o ka liʻiliʻi o ka huina electromagnetic interference o ka pā A ma mua o ka pā B. E nānā kākou i ka hāʻawi ʻana i ka hoʻopā electromagnetic ma kekahi kiko alapine. I ka hoʻoholo ʻana mai ka hāʻawi ʻana i ka hoʻopili electromagnetic ma ke kiko alapine 462MHz i hōʻike ʻia ma ke Kiʻi 8, he liʻiliʻi ka amplitude o ka pā A a liʻiliʻi ka wahi. He laulā nui ka papa B a he ākea ākea ākea.

Hōʻuluʻulu manaʻo o kēia ʻatikala

ʻO ka ʻike electromagnetic piha o ka PCB e hiki ai iā mākou ke loaʻa ka ʻike intuitive o ka PCB holoʻokoʻa, ʻaʻole ia e kōkua wale i nā ʻenekini e hoʻoponopono i nā pilikia EMI/EMC, akā kōkua pū kekahi i nā ʻenekini debug i ka PCB a hoʻomaikaʻi mau i ka maikaʻi hoʻolālā o ka PCB. Pēlā nō, nui nā noi o EMSCAN, e like me ke kōkua ʻana i nā ʻenekinia e hoʻoponopono i nā pilikia susceptibility electromagnetic a pēlā aku.