Tus Qauv thiab Txoj Cai Ua Haujlwm ntawm Lub Suab Qib Meters
Nws feem ntau muaj lub microphone, amplifier, attenuator, hnyav network, detector, taw qhia lub taub hau, thiab lub hwj chim mov.
(1) Lub microphone yog ib qho khoom siv uas hloov cov suab nrov siab rau hauv cov cim hluav taws xob, tseem hu ua microphone lossis sensor. Hom microphones muaj xws li siv lead ua, electret, txav coil, thiab capacitive.
Lub dynamic coil sensor muaj lub vibrating diaphragm, txav tau lub kauj, lub hlau nplaum, thiab lub transformer. Tom qab raug rau acoustic siab, lub vibrating diaphragm pib vibrate thiab tsav lub movable coil ntsia nrog nws kom vibrate nyob rau hauv lub magnetic teb, tsim induced tam sim no. Qhov tam sim no sib txawv raws li qhov loj ntawm acoustic siab ua rau lub vibrating diaphragm. Lub suab siab dua, qhov ntau dua qhov generated tam sim no; Qhov qis dua lub suab siab, qhov me me ntawm qhov generated tam sim no.
Capacitive sensors feem ntau yog tsim los ntawm cov hlau daim nyias nyias thiab cov hlau electrodes uas nyob ib sab, qhov tseem ceeb yog lub tiaj tus capacitor. Cov yeeb yaj kiab hlau thiab hlau electrode tsim ob daim hlau ntawm lub tiaj tus capacitor. Thaum lub diaphragm raug rau lub suab siab, nws deforms, ua rau ib qho kev hloov nyob rau hauv qhov kev ncua deb ntawm ob daim hlau thiab ib tug kev hloov nyob rau hauv capacitance, uas ua rau ib tug alternating voltage uas nws waveform yog proportional rau lub suab siab theem nyob rau hauv lub linear ntau ntawm lub microphone, ua tiav cov hauj lwm ntawm converting suab siab teeb liab rau hauv hluav taws xob siab teeb liab.
Capacitive microphones yog cov microphones zoo tshaj plaws hauv kev ntsuas acoustic, nrog rau qhov zoo xws li qhov loj dynamic ntau, tiaj zaus teb, siab rhiab heev, thiab kev ruaj ntseg zoo nyob rau hauv ib puag ncig kev ntsuas, ua rau lawv siv dav. Vim lub siab tso zis impedance ntawm capacitive sensors, impedance transformation yuav tsum tau los ntawm ib tug preamplifier, uas yog ntsia nyob rau hauv lub suab theem ntsuas nyob ze ntawm qhov chaw uas lub capacitive sensor yog ntsia.
(2) Ntau lub suab nrov hauv tsev thiab txawv teb chaws thiab cov attenuators tam sim no siv ob -theem amplifiers nyob rau hauv amplification circuits, uas yog input amplifiers thiab output amplifiers, uas amplify tsis muaj zog hluav taws xob teeb liab. Lub input attenuator thiab output attenuator yog siv los hloov lub attenuation ntawm lub input teeb liab thiab lub attenuation ntawm cov zis teeb liab, thiaj li hais tias tus pointer ntawm lub meter taub hau taw tes rau qhov tsim nyog txoj hauj lwm, thiab lub attenuation ntawm txhua iav yog 10 decibels. Kev hloov kho ntau yam ntawm lub attenuator siv nyob rau hauv lub input amplifier yog rau kev ntsuas hauv qab kawg (xws li 0-70 decibels), thiab kev hloov ntau yam ntawm lub attenuator siv nyob rau hauv cov zis amplifier yog rau ntsuas * * (70-120 decibels). Lub dials ntawm input thiab output attenuators feem ntau ua nyob rau hauv cov xim sib txawv, thiab tam sim no dub thiab pob tshab feem ntau ua ke ua ke. Vim tias ntau lub suab ntsuas ntsuas muaj qhov siab thiab qis qis ntawm 70 decibels, nws yog ib qho tseem ceeb uas yuav tsum tau tiv thaiv kom tsis txhob dhau qhov kev txwv thaum lub sij hawm tig kom tsis txhob ua rau lub cuab yeej puas.
(3) Lub network hnyav yog tsim los simulate qhov sib txawv rhiab heev ntawm tib neeg auditory xaav ntawm ntau zaus. Nws suav nrog lub network uas tuaj yeem ua raws li cov yam ntxwv ntawm tib neeg lub pob ntseg thiab hloov kho cov teeb liab hluav taws xob kom kwv yees qhov kev xav tau. Hom 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- luj suab theem simulates cov yam ntxwv zaus ntawm qis- suab nrov qis dua 55 decibels rau tib neeg pob ntseg; B- luj suab theem simulates cov yam ntxwv zaus ntawm nruab nrab siv suab nrov xws li 55 mus rau 85 decibels; C- luj suab theem yog ib tug yam ntxwv ntawm simulating siab- siv suab nrov. Qhov sib txawv ntawm peb qhov lus dag nyob rau hauv qib ntawm attenuation ntawm tsawg- zaus ntawm lub suab nrov, nrog A muaj ntau attenuation, ua raws li B, thiab C muaj tsawg attenuation. A- qib suab nrov yog siv dav hauv kev ntsuas suab nrov thoob ntiaj teb vim nws cov yam ntxwv nkhaus nyob ze rau cov yam ntxwv ntawm lub pob ntseg ntawm tib neeg, thaum B thiab C tau maj mam raug txiav tawm.
