Lub ntsiab lus ntawm qhov hnyav hnyav ntawm lub suab nrov meter yog dab tsi?
Nws hais txog qhov piv ntawm cov teeb liab muaj txiaj ntsig rau lub zog tsis muaj suab nrov. Feem ntau, lub hwj chim yog ntsuas raws li qhov ua haujlwm ntawm qhov tam sim no thiab qhov hluav taws xob, yog li lub teeb liab-rau-lub suab nrov piv kuj tuaj yeem suav nrog cov nqi hluav taws xob, uas yog, qhov piv ntawm cov teeb liab theem rau suab nrov, tab sis cov qauv kev suav yog txawv me ntsis. Kev suav cov teeb liab-rau-lub suab sib piv raws li lub zog tso zis piv: S/N=10 log. Kev suav cov teeb liab-rau-nruab nrab raws li qhov voltage: S/N=10 log. Vim lub logarithmic kev sib raug zoo ntawm lub teeb liab-rau-nruab piv piv thiab lub zog los yog voltage, los txhim kho lub teeb liab-rau-suab nrov piv, nws yog ib qho tsim nyog yuav tsum tau nce qhov sib piv ntawm cov nqi tso tawm rau lub suab nrov. Piv txwv li, thaum lub teeb liab-rau- suab nrov piv yog 100dB, qhov tso zis voltage yog 10000 npaug ntawm lub suab nrov. Hauv 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 tias tom qab nyob ntsiag to. Vim lub suab nrov qis, ntau cov ntsiab lus tsis muaj zog zais los ntawm lub suab nrov yuav tshwm sim, ua kom lub suab nrov nrov, txhim kho huab cua zoo, thiab ua kom muaj zog ntau. Tsis muaj cov ntaub ntawv nruj los txiav txim 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 no, nws muaj peev xwm hnov cov suab nrov hauv cov suab paj nruag nyob rau hauv qee qhov kev mloog siab. Ntxiv nrog rau qhov sib piv ntawm cov teeb liab-rau-lub suab nrov, lub tswv yim ntawm lub suab nrov kuj tseem tuaj yeem siv los ntsuas lub suab nrov ntawm lub amplifier. Qhov no yog qhov tseeb-rau-lub suab piv tus nqi suav nrog qhov hluav taws xob, tab sis tus lej yog tus lej tas: 0.775V, thiab tus lej yog lub suab nrov. Yog li ntawd, lub suab nrov thiab lub teeb liab-rau-suab piv piv yog: tus qub yog tus nqi kiag li, thiab tom kawg yog tus lej txheeb ze.
Tom qab cov ntaub ntawv qhia tshwj xeeb hauv ntau phau ntawv qhia khoom, feem ntau muaj lo lus A, lub ntsiab lus A-qhov hnyav, uas yog hais txog qhov hnyav ntawm tus nqi raws li qee cov cai. Raws li tib neeg pob ntseg yog tshwj xeeb tshaj yog rhiab heev rau nruab nrab frequencies, yog hais tias lub teeb liab-rau-suab nrov piv ntawm ib tug amplifier nyob rau hauv lub intermediate zaus ntau yam yog loj txaus, txawm tias lub teeb liab-rau-suab nrov piv yog me ntsis qis nyob rau hauv qis thiab siab zaus ranges. , nws tsis yog ib qho yooj yim rau tib neeg pob ntseg mus ntes. Nws tuaj yeem pom tau tias yog siv txoj kev ntsuas qhov hnyav los ntsuas qhov sib piv ntawm lub teeb liab-rau-lub suab nrov, nws tus nqi yuav twv yuav raug siab dua yog tias tsis siv txoj kev hnyav. Nyob rau hauv cov nqe lus ntawm A qhov hnyav, nws tus nqi yuav siab dua tsis muaj qhov hnyav.
Tsis tas li ntawd, txhawm rau simulate qhov sib txawv ntawm tib neeg kev hnov lus pom ntawm ntau zaus, lub network tau teeb tsa nyob rau hauv lub suab ntsuas ntsuas uas tuaj yeem ua raws li cov yam ntxwv ntawm lub pob ntseg ntawm tib neeg lub pob ntseg thiab kho cov teeb liab hluav taws xob kom kwv yees qhov kev xav tau. Lub network no hu ua lub network hnyav. Lub suab siab ntsuas ntsuas los ntawm qhov hnyav network tsis yog lub hom phiaj lub cev muaj nuj nqis ntawm lub suab siab (hu ua linear sound pressure level), tab sis lub suab siab kho rau 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. A-hnyav suab theem simulates cov yam ntxwv zaus ntawm cov suab nrov qis qis qis dua 55dB rau tib neeg pob ntseg, B-hnyav suab theem simulates cov yam ntxwv zaus ntawm cov suab nrov nruab nrab. nruab nrab ntawm 55dB thiab 85dB, thiab C-weighted suab theem simulates tus yam ntxwv zaus ntawm lub suab nrov nrov. Qhov sib txawv tseem ceeb ntawm peb yog qib ntawm attenuation ntawm tsawg zaus ntawm lub suab nrov, nrog A muaj ntau attenuation, ua raws li B, thiab C muaj tsawg tshaj plaws. A-weighted suab theem yog dav siv nyob rau hauv lub suab nrov ntsuas thoob ntiaj teb vim nws cov yam ntxwv nkhaus nyob ze rau lub auditory yam ntxwv ntawm tib neeg pob ntseg, thaum B thiab C yog maj mam phased tawm.
