Momwe mungafotokozere ndikuwerengera dB, dBm, dBw… pali kusiyana kotani pakati pawo?

Momwe mungafotokozere ndikuwerengera dB, dBm, dBw… pali kusiyana kotani pakati pawo?

dB iyenera kukhala lingaliro lofunikira kwambiri pakulankhulana opanda zingwe.nthawi zambiri timati "kutayika kwapatsirana ndi xx dB," "mphamvu yotumizira ndi xx dBm," "kupindula kwa mlongoti ndi xx dBi" ...

Nthawi zina, dB X iyi imatha kusokonezeka komanso kuyambitsa zolakwika zowerengera.Ndiye pali kusiyana kotani pakati pawo?

Nkhani iyenera kuyamba ndi dB.

Zikafika pa dB, lingaliro lodziwika bwino ndi 3dB!

3dB nthawi zambiri imawonekera pazithunzi zamphamvu kapena BER (Bit Error Rate).Koma, kwenikweni, palibe chinsinsi.

Dontho la 3dB limatanthauza kuti mphamvu imachepetsedwa ndi theka, ndipo mfundo ya 3dB imatanthauza mphamvu ya theka.

+3dB imatanthauza mphamvu yowirikiza kawiri, -3Db ikutanthauza kuti kuchepa ndi ½.Kodi izi zinachokera bwanji?

Ndikosavuta kwenikweni.Tiyeni tiwone njira yowerengera ya dB:

dB imayimira mgwirizano pakati pa mphamvu P1 ndi mphamvu ya P0.Ngati P1 ili kawiri P0, ndiye:

ngati P1 ndi theka la P0, ndiye,

Pamalingaliro oyambira ndi magwiridwe antchito a logarithms, mutha kuwunikanso masamu a logarithms.

[Funso]: Mphamvu imachulukitsidwa ndi 10time.Ndi dB zingati pamenepo?

Chonde kumbukirani ndondomeko apa.

+ 3 * 2

+ 10 * 10

-3/2

-10/10

+ 3dB amatanthauza kuti mphamvu imawonjezedwa ka 2;

+ 10dB zikutanthauza kuti mphamvuyo imawonjezedwa ka 10.

-3 dB amatanthauza kuti mphamvu imachepetsedwa kukhala 1/2;

-10dB amatanthauza kuti mphamvu imachepetsedwa kukhala 1/10.

Zitha kuwoneka kuti dB ndi mtengo wachibale, ndipo cholinga chake ndikuwonetsa nambala yayikulu kapena yaying'ono mwachidule.

Fomula iyi imatha kupangitsa kuti tiziwerengera komanso kufotokozera kwathu.Makamaka pojambula fomu, mutha kuyidzaza ndi ubongo wanu.

Ngati mukumvetsa dB, tsopano, tiyeni tikambirane manambala abanja la dB:

Tiyeni tiyambe ndi dBm yomwe imagwiritsidwa ntchito kwambiri ndi dBw.

dBm ndi dBw akuyenera kusintha mphamvu ya P0 mu fomula ya dB ndi 1 mW, 1W.

1mw ndi 1w ndi mfundo zenizeni, kotero dBm ndi dBw zikhoza kuyimira mtengo wathunthu wa mphamvu.

M'munsimu ndi tebulo kutembenuka mphamvu kwa mfundo zanu.

Tiyenera kukumbukira:

1w = 30dBm

30 ndiye benchmark, yomwe ili yofanana ndi 1w.

Kumbukirani izi, ndikuphatikiza zam'mbuyo "+3 *2, +10*10, -3/2, -10/10" mutha kuwerengera zambiri:

[Funso] 44dBm = ?w

Apa, tiyenera kuzindikira kuti:

Kupatula 30dBm kumanja kwa equation, zina zogawanika ziyenera kuwonetsedwa mu dB.

[Chitsanzo] Ngati mphamvu yotulutsa A ndi 46dBm ndipo mphamvu yotulutsa B ndi 40dBm, tinganene kuti A ndi 6dB wamkulu kuposa B.

[Chitsanzo] Ngati mlongoti A ndi 12 dBd, mlongoti B ndi 14dBd, tinganene kuti A ndi 2dB wocheperapo kuposa B.

Mwachitsanzo, 46dB zikutanthauza kuti P1 ndi 40 zikwi nthawi P0, ndipo 46dBm zikutanthauza kuti mtengo wa P1 ndi 40w.Pali kusiyana kumodzi kokha kwa M, koma tanthauzo lingakhale losiyana kotheratu.

Banja la dB wamba lilinso ndi dBi, dBd, ndi dBc.Njira yawo yowerengera ndi yofanana ndi njira yowerengera ya dB, ndipo imayimira kuchuluka kwa mphamvu.

Kusiyana kwake ndikuti miyezo yawo yolozera ndi yosiyana.Ndiko kuti, tanthauzo la mphamvu yofotokozera P0 pa denominator ndi yosiyana.

Nthawi zambiri, kuwonetsa kupindula komweko, kofotokozedwa mu dBi, ndi 2.15 kukulirapo kuposa kufotokozedwa mu dBd.Kusiyanaku kumayambitsidwa ndi mayendedwe osiyanasiyana a tinyanga tiwiri.

Kuphatikiza apo, banja la dB silingangoyimira kupindula ndi kutayika kwa mphamvu komanso kuyimira ma voltage, apano, ndi ma audio, ndi zina zambiri.

Tiyenera kuzindikira kuti kuti tipeze mphamvu, timagwiritsa ntchito 10lg (Po / Pi), ndipo pamagetsi ndi panopa, timagwiritsa ntchito 20lg (Vo / Vi) ndi 20lg (Lo / Li)

Kodi izi 2 zinachokera bwanji?

Nthawi 2 izi zimachokera ku lalikulu la njira yosinthira mphamvu yamagetsi.N-mphamvu mu logarithm imafanana ndi n nthawi pambuyo powerengera.

Mutha kuwunikanso maphunziro anu asukulu yasekondale okhudzana ndi kutembenuka kwapakati pa mphamvu, voteji, ndi zamakono.

Pomaliza, ndidatsatira achibale ena akuluakulu a dB kuti mufotokozere.

Mtengo wofananira:

Mtengo weniweni:

Ndipo, tiyeni tiwone ngati mukumvetsa kapena ayi.

[Funso] 1. Mphamvu ya 30dBm ndi

[Funso] 2. Poganiza kuti kuchuluka kwa kuchuluka kwa selo ndi 46dBm, pamene pali 2 tinyanga, mphamvu ya mlongoti umodzi ndi.