Ngati mwagwirapo ntchito pawailesi yakanema kwakanthawi, muyenera kuti mwawona magawowa atalembedwa m'mabuku ena a zida zoulutsira mawayilesi monga FM antenna kapena RF amplifier: dB, dBi, dBm. Amawoneka ofanana, koma mukudziwa zomwe akutanthauza komanso momwe mungawasiyanitse? Mukawerenga nkhaniyi, mudzadziwa tanthauzo lake komanso momwe mungawasiyanitse.

Timasangalala

• Tanthauzo la Kupindula
• Tanthauzo ndi Kusiyana kwa dB, dBi ndi dBm
• FAQ
• Kutsiliza

Tanthauzo la Kupindula

Tisanafike pamfundoyi, tiyeni tiyankhe mafunso awiri: phindu la an Mlongoti wa FM amatanthauza chiyani?

Kutengera Wikipedia, mu mlongoti wotumizira, phindu limafotokoza momwe mlongoti umasinthira mphamvu zolowetsa kukhala mafunde a wailesi olunjika mbali ina yake. Mu mlongoti wolandila, phindu limafotokoza momwe mlongoti umasinthira mafunde a wailesi kuchokera kunjira inayake kukhala mphamvu yamagetsi. Ngati palibe chitsogozo chomwe chafotokozedwa, phindu limamveka kuti likutanthauza phindu lapamwamba la phindu, kupindula komwe kumachokera ku lobe yaikulu ya antenna.

Mwachidule, mlongoti wa FM sungathe kupititsa patsogolo mphamvu ya chipangizo chotumizira kapena chipangizo cholandira chokha, koma mlongotiyo ukhoza kuyang'ana kwambiri mafunde awa kapena mafunde a wailesi kudera linalake. Mwanjira iyi, mphamvu ya mafunde a wailesi yotulutsidwa ndi mlongoti kumbali iyi idzakhala yamphamvu kuposa yoyambayo, zomwe zikutanthauzanso kuti mphamvu ya mafunde a wailesi kumbali zina idzakhala yofooka kuposa yoyamba. Chifukwa chake kupindula ndi kuchuluka kwamphamvu kwa mafunde awayilesi komwe kumakhala ndi mphamvu yamphamvu kwambiri ya radiation mpaka mphamvu yoyambira yawayilesi.

Kupindula Kosiyanasiyana kwa Mlongoti wa Isotropic ndi Mlongoti Wopeza Bwino Kwambiri

Tanthauzo ndi Kusiyana kwa dB, dBi ndi dBm

Pambuyo pomvetsetsa mfundo yopezera phindu, ndikosavuta kumvetsetsa magawo atatu a dB, dBi, ndi dBm.

Tanthauzo la dB

Tinaphunzira kusukulu kuti dB imayimira kukweza kwa mawu. Komabe, ndizosiyana m'munda wa RF. Njira yake ndi dB=10log(x/y)(pamene x ndi Y imayimira mphamvu ya radiation ya tinyanga ziwirizo) ndipo imayimira kusiyana pakati pa mphamvu za tinyanga ziwirizo(kupindula kapena kutayika)

Pogwiritsa ntchito kuwerengera, tikhoza kudziwa kuti ngati x ali wofooka kuposa y, dB ndi yolakwika; Pamene x ndi y ali ofanana, dB ndi wofanana ndi 0; Pamene x = 2y, dB ikufanana ndi 3. Mofananamo, 6dB amatanthauza x ndi 4 kuchulukitsa y ndipo 12dB amatanthauza x ndi 16 nthawi y. Zindikirani kuti ngati mukufuna kuyeza kupindula kwenikweni kapena kusiyana kwenikweni kwa mphamvu ya mlongoti wamawaya, chonde ganizirani kutayika kwa chingwe cha RF chokha.

Tanthauzo la dBi

Ngati mukufuna kufananiza kuchuluka kwa ma radiation a antenna yolowera njira ndi mlongoti wa omnidirectional, muyenera kutenga dBi ngati gawo, pomwe "i" imayimira isotopic, ndipo mawerengero a dBi ndi ofanana ndi a dBi.

Chifukwa mlongoti wa omnidirectional udzawunikira siginecha yawayilesi ndi "gawo" langwiro, ndiye kuti, ili ndi mphamvu yofananira mbali iliyonse. Mlongoti ukakhala ndi phindu kunjira inayake, lobe yake imacheperako, ndiye kuti, mlongoti wa wayilesi ya FM umatenga mbali ina ngati njira yayikulu yowunikira ma radiation, ndipo mphamvu ya ma radiation imakhala yamphamvu kuposa mphamvu ya radiation yoyambirira. Chiŵerengero cha mphamvu ya ma radiation ya ngodya yaikulu ya chezayi ndi mphamvu ya cheza yoyambilira ndiyo kupindula kwa mlongoti wolunjikawu. Choncho, pamene dBi ndi yaikulu kuposa 0, zimasonyeza kuti mlongoti uli ndi chiwongolero.

Ma Radiation a Antenna ya Isotropic

Tanthauzo la dBm

Ngakhale dBm imawoneka ngati dBi, siyiyimira mphamvu ya radiation. "M" mu dBm imayimira milliwatts (MW), yomwe ili yofanana ndi dBi, ilinso ndi mtengo wofanana, koma imayimira mtengo wofanana wa mphamvu yotumizira ndi 1MW monga mtengo wofotokozera. Njirayi ndi: dBm = 10 chipika (P1/1MW)

Ngakhale dBm ndi mtengo wachibale, imatha kusinthidwa kukhala mphamvu yeniyeni ya zida pambuyo pa kutembenuka kwa unit. Mwachitsanzo, 0dbm = 1MW, 1dbm = 1.3MW, 10dBm = 1W, 60dbm = 1000W... Zitha kuwoneka kuti zingagwiritse ntchito mfundo zosavuta kwambiri kuti ziwonetsere mphamvu zochepa kwambiri kapena mphamvu zazikulu kwambiri. Chifukwa chake, mphamvu yeniyeni ya zida zosiyanasiyana idzawonetsedwa mu dBm.

Kusiyana pakati pa dB, dBi ndi dBm

Mwachidule, dB, dBm, ndi dBm onse ndi ofanana, koma ali ndi zosiyana ziwiri zotsatirazi:

1. DB ndi dBi amagwiritsidwa ntchito kuyimira mphamvu yachibale (kupindula kapena kutayika) kwa ma radiation a mlongoti, pamene dBm imagwiritsidwa ntchito kuimira mphamvu yeniyeni ya zipangizo.
2. dB ndiye mtengo wofananira wa kusiyana kwamphamvu kwa ma radiation pakati pa tinyanga ziwiri, ndipo dBi ndiye kufananitsa kwamphamvu kwa siginecha ya wailesi isanakwane komanso itatha (kapena kuwongolera).

Mafunso Ofunsidwa Kawirikawiri

1. Q: Kodi Kupindula kwa dB kwa Mlongoti Wakuwulutsa kwa FM ndi chiyani?

A: Ndikutha kuwunikira mochulukirapo kapena pang'ono komwe kumayendera ma FM Broadcast Antennas.

DB imayesedwa ndi chiŵerengero cha mphamvu, panopa kapena voteji ya zizindikiro ziwiri. Ndilo gawo lomwe limagwiritsidwa ntchito kwambiri kuti apindule.

2. Q: Chifukwa chiyani Mphamvu ya Signal Imayesedwa ndi dB?

A: Chifukwa mphamvu ya siginecha imasiyanasiyana motsatana koma osati motsatana.

Timagwiritsa ntchito dB kuyeza mphamvu ya siginecha chifukwa mphamvu zama siginecha zimasiyana motsatana, osati motsatira mzere. Sikelo ya logarithmic imalola manambala osavuta kuyimira kusintha kwakukulu pamasinthidwe azizindikiro. 

3. Q: Kodi Kupeza kwa -3 dB Kumatanthauza Chiyani kwa Mlongoti?

A: -3dB kupindula kumatanthauza kuti kupindula kumachepetsedwa kufika ku 70.71% ya mlingo wake waukulu.

Kupeza -3dB kumatanthawuza kuti kuchuluka kwa phindu kumachepetsedwa mpaka 70.71% ya mlingo wake waukulu. Kapena tikhoza kunena kuti -3dB mfundo imakhalanso nthawi zambiri zomwe phindu la dongosololi lachepetsedwa mpaka 0.707 la mtengo wake waukulu.

4. Q: Kodi dBi yapamwamba ndi yabwino kuposa yotsika?

A:  Ayi ndithu, ndalama zonse zili ndi mbali ziwiri. DBi yapamwamba imatanthawuza kuwunikira mopitirira koma mocheperapo.

Kukwera kwa chiwerengero cha dBi cha mlongoti, kumapangitsa kuti phindu lake likhale lokwera, koma locheperapo pamtundu waukulu wamunda. Zimatanthawuza kuti mphamvu ya chizindikiro idzapita patsogolo koma m'njira yopapatiza. Ngati mukufuna kuwunikira mokulirapo, muyenera kuwonjezera tinyanga zambiri.

Kutsiliza

Timaphunzira matanthauzo ndi kusiyana kwa dB, dBi, ndi dBm kudzera pazomwe zili pamwambapa. Ndizothandiza kwambiri kuti mudziwe bwino chiphunzitso cha antenna musanalowe mugawo la RF. Ngati mukufuna kudziwa zambiri za kuwulutsa, kapena mukufuna zida zilizonse zowulutsira pawayilesi zogulitsa, chonde omasuka lumikizanani ndi gulu lathu la akatswiri a RF, mudzayankhidwa posachedwa. Ndipo osayiwala kugawana nawo blog ngati ili yothandiza kwa inu!

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