Lub suab ntsuas ntsuas cov ntsiab lus, cov txheej txheem pov thawj, thiab kev txheeb xyuas cov qauv sab hauv ntawm cov qauv muaj feem xyuam
Lub suab nrov meter, tseem hu ua lub suab ntsuas ntsuas, yog ib qho cuab yeej uas kwv yees ntsuas lub suab nrov ntawm kev lag luam, suab nrov hauv tsev, thiab lub suab nrov raws li tib neeg lub suab nrov.
Lub suab nrov yog hais txog lub suab siab (dB) lossis qib suab nrov (phon) ntsuas los ntawm lub suab ntsuas ntsuas thiab kho rau kev hnov lus pom.
Raws li qhov tseeb ntawm kev ntsuas 1000Hz ntshiab tones nrog lub suab ntsuas ntsuas raws li cov txheej txheem, nyob rau xyoo 1960, suab qib tau muab faib ua ob pawg thoob ntiaj teb: precision suab qib ntsuas thiab cov suab suab zoo tib yam.
Peb lub teb chaws kuj siv txoj kev no. Feem ntau muaj peb hom suab nrov sib txuas: A, B, thiab C. A-qhov hnyav ntawm lub suab simulates cov yam ntxwv zaus ntawm cov suab nrov qis qis qis dua 55 decibels rau tib neeg pob ntseg; B-hnyav suab theem simulates cov yam ntxwv zaus ntawm lub suab nrov nruab nrab ntawm 55 txog 85 decibels; C-weighted suab theem yog ib tug yam ntxwv ntawm simulating high-siv suab nrov.
Txij li thaum xyoo 1970s, qee lub tebchaws tau qhia plaub hom kev faib tawm, xws li Hom 0, Hom 1, Hom 2, thiab Hom 3. Lawv qhov tseeb yog ± 0.4dB, ± 0.7dB, ± 1.0dB, thiab ± 1.5dB, feem.
Raws li cov khoom siv hluav taws xob sib txawv siv nyob rau hauv lub suab ntsuas ntsuas, nws tseem tuaj yeem muab faib ua ob hom: AC hom thiab DC hom suab ntsuas ntsuas siv cov roj teeb qhuav, qhov kawg ntawm qhov tseem tuaj yeem nqa tau. Portable muaj qhov zoo ntawm qhov me me, lub teeb yuag, thiab siv tau yooj yim ntawm qhov chaw.
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.
(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.
(3) Feem ntau muaj peb hom kev tes hauj lwm hnyav: A, B, thiab C. A-qhov hnyav ntawm lub suab simulates cov yam ntxwv zaus ntawm cov suab nrov qis qis qis dua 55 decibels rau tib neeg pob ntseg; B-hnyav suab theem simulates cov yam ntxwv zaus ntawm lub suab nrov nruab nrab ntawm 55 txog 85 decibels; C-weighted suab theem yog ib tug yam ntxwv ntawm simulating high-siv suab nrov.
(4) Txhawm rau kom pom cov teeb liab amplified los ntawm lub ntsuas ntsuas, cov ntsuas ntsuas thiab ntsuas lub taub hau kuj tseem yuav tsum tau hloov pauv hloov pauv hluav taws xob sai sai rau hauv kev hloov pauv DC voltage qeeb.
