Fundamental Frequency vs Natural Frequency
Natural zaus thiab qhov tseem ceeb zaus yog ob lub nthwv dej ntsig txog qhov tshwm sim uas tseem ceeb heev. Cov phenomena no tseem ceeb heev nyob rau hauv cov teb xws li suab paj nruag, kev tsim technologies, kev tiv thaiv kev puas tsuaj, acoustics thiab feem ntau ntawm cov natural system tsom xam. Nws yog ib qho tseem ceeb kom muaj kev nkag siab meej hauv cov ntsiab lus no kom ua tau zoo hauv cov haujlwm no. Nyob rau hauv tsab xov xwm no, peb yuav tham txog dab tsi yog qhov tseem ceeb zaus thiab ntuj zaus yog, lawv cov ntsiab lus, kev siv, cov phenomena txuas nrog lub ntuj zaus thiab qhov tseem ceeb zaus, lawv qhov zoo sib xws thiab thaum kawg qhov sib txawv ntawm ntuj zaus thiab qhov tseem ceeb zaus.
Natural Frequency yog dab tsi?
Txhua qhov system muaj cov cuab yeej hu ua ntuj zaus. Lub kaw lus yuav ua raws li qhov zaus, yog tias lub kaw lus yuav tsum tau muab nrog me me oscillation. Lub ntuj zaus ntawm ib qho system tseem ceeb heev. Cov xwm txheej xws li av qeeg thiab cua tuaj yeem ua kev puas tsuaj rau cov khoom nrog tib lub ntuj zaus raws li qhov xwm txheej nws tus kheej. Nws yog ib qho tseem ceeb heev uas yuav tsum nkag siab thiab ntsuas qhov zaus ntawm lub cev ntawm lub cev txhawm rau tiv thaiv nws los ntawm kev puas tsuaj ntuj tsim. Ntuj zaus yog ncaj qha cuam tshuam nrog resonance. Thaum lub kaw lus (piv txwv li lub pendulum) tau txais me me oscillation, nws yuav pib viav vias. Qhov zaus uas nws swings yog lub ntuj zaus ntawm qhov system. Tam sim no xav txog ib lub sij hawm sab nraud quab yuam siv rau lub system. Qhov zaus ntawm qhov kev quab yuam sab nraud no tsis tas yuav zoo ib yam li lub ntuj zaus ntawm qhov system. Lub zog no yuav sim oscillate lub system mus rau zaus ntawm lub zog. Qhov no tsim cov qauv tsis sib xws. Qee lub zog los ntawm lub zog sab nraud yog absorbed los ntawm lub system. Tam sim no cia peb xav txog cov ntaub ntawv uas cov frequencies yog tib yam. Nyob rau hauv rooj plaub no, lub pendulum yuav ywj siab viav vias nrog lub zog siab tshaj plaws absorbed los ntawm sab nraud quab yuam. Qhov no hu ua resonance. Cov kab ke xws li lub tsev, hluav taws xob thiab hluav taws xob circuits, kho qhov muag, suab tshuab thiab txawm tias cov kab mob lom muaj cov zaus ntuj. Lawv tuaj yeem ua rau hauv daim ntawv ntawm impedance, oscillation, lossis superposition, nyob ntawm qhov system.
Zoo Qhov Tseem Ceeb yog dab tsi?
Fundamental zaus yog ib lub tswv yim sib tham hauv cov nthwv dej sawv. Xav txog ob lub nthwv dej zoo ib yam, uas tau taug kev hauv qhov sib txawv. Thaum ob lub nthwv dej sib ntsib, qhov tshwm sim yog hu ua yoj sawv. Qhov sib npaug ntawm yoj mus rau hauv + x kev taw qhia yog y=A sin (ωt – kx), thiab qhov sib npaug rau ib tug zoo xws li yoj mus rau hauv lub -x kev taw qhia yog y=A sin (ωt + kx). Los ntawm lub hauv paus ntsiab lus ntawm superposition, lub resultant waveform los ntawm qhov sib tshooj ntawm ob yog y=2A sin (kx) cos (ωt). Qhov no yog qhov sib npaug ntawm qhov sawv nthwv dej. 'x' yog qhov deb ntawm lub hauv paus chiv keeb; rau qhov muab x tus nqi, qhov 2A sin (kx) ua qhov tsis tu ncua. Kev txhaum (kx) txawv ntawm -1 thiab +1. Yog li ntawd, qhov siab tshaj plaws amplitude ntawm lub system yog 2A. Lub hauv paus zaus yog cov cuab yeej ntawm qhov system. Ntawm qhov tseem ceeb zaus, ob qhov kawg ntawm lub tshuab tsis yog oscillating, thiab lawv hu ua nodes. Qhov nruab nrab ntawm qhov system yog oscillating nrog lub siab tshaj plaws amplitude, thiab nws yog hu ua antinode.
Dab tsi yog qhov txawv ntawm ntuj zaus thiab qhov tseem ceeb zaus?
• Ntuj zaus yog ib yam khoom uas txhawj txog oscillations, tiam sis qhov zaus yog ib yam khoom uas txhawj txog nthwv dej.
• Txhua lub kaw lus muaj qhov ntau zaus, tab sis qhov tseem ceeb zaus tshwm sim hauv qee lub tshuab.
• Rau qhov tseem ceeb zaus, qhov superposition ntawm kev sib txawv ntawm kev mus los ntawm ob lub nthwv dej zoo ib yam yog xav tau, tab sis rau qhov zaus, tsuas yog yuav tsum muaj ib qho oscillation xwb.
