Qhov tseem ceeb ntawm qhov hnyav ntawm lub suab ntsuas ntsuas (sound level meters)
Teeb liab-rau-suab nrov piv, hu ua teeb liab-rau-nrov piv los yog teeb liab-rau-nrov piv
Nws hais txog qhov piv ntawm cov teeb liab muaj txiaj ntsig rau lub suab nrov tsis muaj zog. Feem ntau ntsuas hauv cov plhaub. Vim hais tias lub hwj chim yog qhov ua haujlwm ntawm qhov tam sim no thiab qhov hluav taws xob, lub teeb liab-rau-suab nrov piv kuj tuaj yeem suav nrog cov nqi hluav taws xob, uas yog, qhov sib piv ntawm theem teeb liab mus rau lub suab nrov, tab sis cov qauv kev suav yog txawv me ntsis. Xam cov teeb liab-rau-nruab piv raws li lub zog piv: S/N=10 log Xam lub teeb liab-rau-nruab nrab raws li qhov voltage: S/N=10 log Txij thaum lub teeb liab-rau -noise ratio muaj logarithmic kev sib raug zoo nrog lub hwj chim los yog voltage, los txhim kho lub teeb liab-rau-suab nrov piv, nws yuav tsum tau loj dua Qhov tseem ceeb tshaj qhov sib piv ntawm cov nqi tso zis thiab lub suab nrov. Piv txwv li, thaum lub teeb liab-rau- suab nrov piv yog 100dB, qhov tso zis voltage yog 10,{16}} npaug ntawm lub suab nrov. Hais txog hluav taws xob circuits, qhov no tsis yog ib txoj haujlwm yooj yim.
Yog hais tias lub amplifier muaj lub teeb liab-rau-suab nrov piv, nws txhais tau hais tias North View nyob ntsiag to. Vim hais tias lub suab nrov qis, ntau lub suab tsis muaj zog cov ntsiab lus zais los ntawm lub suab nrov yuav tshwm sim, uas yuav ua rau kom lub suab nrov nrov, ntxiv dag zog rau kev nkag siab ntawm huab cua, thiab ua kom muaj zog ntau. Tsis muaj cov ntaub ntawv txiav txim nruj los ntsuas seb lub teeb liab-rau-nruab nrab ntawm lub amplifier puas zoo lossis phem. Feem ntau hais lus, nws yog qhov zoo dua kom muaj lub teeb liab-rau-lub suab sib piv ntawm li 85dB lossis siab dua. Yog tias nws qis dua tus nqi tus qauv, nws yuav hnov ntxhiab hauv qhov sib txawv ntawm cov suab paj nruag hauv qee qhov xwm txheej siab. suab nrov. Ntxiv rau qhov sib piv ntawm cov teeb liab-rau-nruab nrab, lub tswv yim ntawm lub suab nrov kuj tuaj yeem siv los ntsuas lub suab nrov nrov. Qhov no yog qhov tseeb-rau-suab nrov piv tus nqi suav nrog qhov voltage, tab sis tus denominator yog tus lej tas: 0.775V, thiab tus lej yog Noise voltage, yog li qhov sib txawv ntawm lub suab nrov thiab teeb liab-rau-suab nrov piv yog: tus qub yog ib tug ***, thiab tom kawg yog tus txheeb ze tus lej.
Tom qab cov lus qhia tshwj xeeb hauv cov khoom siv phau ntawv, feem ntau yog lo lus A, uas txhais tau tias A-qhov hnyav, uas txhais tau hais tias A-hnyav. Qhov hnyav txhais tau hais tias qee tus nqi tau raug hloov kho raws li qee txoj cai los ntsuas qhov hnyav. Vim hais tias tib neeg pob ntseg Nws yog tshwj xeeb tshaj yog rhiab heev rau nruab nrab zaus, yog li yog hais tias lub teeb liab-rau-suab nrov piv ntawm ib tug amplifier nyob rau hauv nruab nrab-frequency band yog loj txaus, txawm hais tias lub teeb liab suab nrov yog me ntsis qis dua qhov tsawg-frequency thiab siab. -frequency bands, nws yuav tsis yooj yim pom los ntawm tib neeg pob ntseg. Nws tuaj yeem pom tau tias yog siv txoj kev hnyav los ntsuas lub teeb liab-rau-lub suab nrov piv, tus nqi yuav twv yuav raug siab dua qhov tsis muaj qhov hnyav. Nyob rau hauv cov nqe lus ntawm A qhov hnyav, nws tus nqi siab dua qhov uas tsis muaj qhov hnyav.
Tsis tas li ntawd, txhawm rau simulate qhov sib txawv rhiab heev ntawm tib neeg kev hnov lus ntawm ntau zaus, lub suab ntsuas ntsuas tau nruab nrog lub network uas tuaj yeem simulate qhov hnov lus ntawm tib neeg pob ntseg thiab hloov kho cov teeb liab hluav taws xob rau qhov kwv yees tus nqi ntawm kev hnov lus. . Lub network no hu ua Weighted network. Lub suab siab ntsuas ntsuas los ntawm qhov hnyav network tsis yog lub suab siab ntawm lub hom phiaj lub cev (hu ua linear sound pressure level), tab sis lub suab siab hloov kho los ntawm kev hnov lus, hu ua weighted sound level lossis suab nrov.
Feem ntau muaj peb hom kev tes hauj lwm hnyav: A, B, thiab C. Qib A-hnyav lub suab simulates cov yam ntxwv zaus ntawm tib neeg lub pob ntseg mus rau lub suab qis qis qis dua 55dB, B-weighted suab theem simulates zaus cov yam ntxwv ntawm nruab nrab. - siv lub suab nrov ntawm 55dB txog 85dB, thiab C-qhov hnyav ntawm lub suab simulates lub suab nrov nrov. yam ntxwv. Qhov sib txawv tseem ceeb ntawm peb yog qhov degree ntawm attenuation ntawm cov khoom siv suab nrov tsawg. A attenuates tshaj plaws, B qhov thib ob, thiab C qhov tsawg tshaj plaws. A-weighted suab theem tam sim no yog siv dav tshaj plaws hauv kev ntsuas suab nrov hauv ntiaj teb vim nws cov yam ntxwv nkhaus yog ze rau lub cev lub cev ntawm tib neeg pob ntseg. B thiab C tau maj mam tsis siv lawm.
