Yuav piav qhia thiab xam dB, dBm, dBw… qhov txawv ntawm lawv li cas?

Yuav piav qhia thiab xam dB, dBm, dBw… qhov txawv ntawm lawv li cas?

dB yuav tsum yog lub tswv yim yooj yim tshaj plaws hauv kev sib txuas lus wireless.

Yog li, qhov txawv ntawm lawv yog dab tsi?

Qhov teeb meem yuav tsum pib nrog dB.

Tab sis, qhov tseeb, tsis muaj qhov paub tsis meej.

Qhov no tuaj li cas?

Nws yog qhov ua tau yooj yim heev.

Yog tias P1 yog ob zaug P0, ces:

Yog tias P1 yog ib nrab ntawm P0, ces,

Thov nco ntsoov ib qho qauv ntawm no.

+3 * 2

+ 10 * 10

-3 / 2

-10 / 10

Cov qauv no tuaj yeem pab txhawb peb kev suav thiab piav qhia.Tshwj xeeb tshaj yog thaum kos ib daim ntawv, koj tuaj yeem sau nws nrog koj lub hlwb.

Yog tias koj nkag siab dB, tam sim no, cia peb tham txog dB tsev neeg tus lej:

dBm thiab dBw yog los hloov lub zog siv P0 hauv cov qauv dB nrog 1 mW, 1W

1mw thiab 1w yog qhov tseem ceeb, yog li dBm thiab dBw tuaj yeem sawv cev rau tus nqi ntawm lub zog.

Hauv qab no yog lub rooj hloov hluav taws xob rau koj siv.

Nco ntsoov qhov no, thiab ua ke ua ntej "+3 * 2, + 10 * 10, -3/2, -10/10" koj tuaj yeem ua ntau qhov kev suav:

w

Tsuas yog 30dBm ntawm sab xis ntawm qhov sib npaug, qhov seem ntawm cov khoom sib cais yuav tsum tau qhia hauv dB.

[Piv txwv] Yog tias A lub zog tso zis yog 46dBm thiab lub zog tso zis ntawm B yog 40dBm, nws tuaj yeem hais tias A yog 6dB ntau dua B.

[Piv txwv] Yog tias tus kav hlau txais xov A yog 12 dBd, tus kav hlau txais xov B yog 14dBd, nws tuaj yeem hais tias A yog 2dB me dua B.

Piv txwv li, 46dB txhais tau hais tias P1 yog 40 txhiab zaus P0, thiab 46dBm txhais tau tias tus nqi ntawm P1 yog 40w.Tsuas muaj ib qho M txawv xwb, tab sis lub ntsiab lus tuaj yeem sib txawv kiag li.

Hom dB tsev neeg kuj muaj dBi, dBd, thiab dBc.Lawv txoj kev suav yog tib yam li dB txoj kev suav, thiab lawv sawv cev rau tus nqi txheeb ze ntawm lub zog.

Feem ntau, kev nthuav qhia tib qhov nce, qhia hauv dBi, yog 2.15 loj dua li qhia hauv dBd.Qhov sib txawv no yog tshwm sim los ntawm kev sib txawv ntawm ob lub kav hlau txais xov.

Tsis tas li ntawd, tsev neeg dB tuaj yeem tsis tsuas yog sawv cev qhov nce thiab lub zog poob tab sis kuj sawv cev rau qhov voltage, tam sim no, thiab suab, thiab lwm yam.

Nws yuav tsum raug sau tseg tias rau qhov nce ntawm lub zog, peb siv 10lg (Po / Pi), thiab rau qhov voltage thiab tam sim no, peb siv 20lg (Vo / Vi) thiab 20lg (Lo / Li)

Qhov no 2 zaug yog muab los ntawm cov square ntawm lub zog hluav taws xob hloov pauv mis.

Koj tuaj yeem tshuaj xyuas koj cov chav kawm physics hauv tsev kawm theem siab txog kev hloov pauv kev sib raug zoo ntawm lub zog, qhov hluav taws xob, thiab tam sim no.

Thaum kawg, kuv tau ua raws li qee tus neeg hauv tsev neeg loj dB rau koj siv.