Overtone vs Harmonic
Kev tshaj tawm thiab kev sib haum xeeb yog ob lub ntsiab lus sib tham hauv qab nthwv dej nyob ruaj khov hauv yoj tshuab. Ob lub ntsiab lus no ua lub luag haujlwm tseem ceeb hauv kev ua haujlwm xws li acoustics, Audio engineering thiab txawm tias mechanical engineering. Nws yog ib qho tseem ceeb heev uas yuav tsum muaj kev nkag siab zoo hauv cov ntsiab lus no thiaj li ua tau zoo hauv cov haujlwm no. Hauv tsab xov xwm no, peb yuav tham txog dab tsi overtone thiab harmonic yog, lawv qhov zoo sib xws, cov ntsiab lus ntawm overtone thiab harmonic, thiab thaum kawg qhov sib txawv ntawm overtone thiab harmonic.
YHarmonic yog dab tsi?
Yuav kom nkag siab lub tswv yim ntawm kev sib haum xeeb kom raug, ib tus yuav tsum xub nkag siab lub ntsiab lus ntawm kev sawv nthwv dej thiab qhov tseem ceeb zaus. Xav txog ob lub nthwv dej zoo ib yam taug kev hauv qhov sib txawv; thaum ob lub nthwv dej sib ntsib, (superimpose), qhov tshwm sim yog hu ua yoj sawv. Qhov sib npaug ntawm nthwv dej mus rau hauv qhov kev taw qhia + x yog y=A sin (ωt – kx), thiab qhov sib npaug ntawm cov nthwv dej zoo sib xws nyob rau hauv txoj kev –x yog y=A sin (ωt + kx). Los ntawm lub hauv paus ntsiab lus ntawm superposition, lub resultant waveform los ntawm overlapping ntawm ob yog y=2A sin (kx) cos (ωt). Qhov no yog qhov sib npaug ntawm qhov sawv nthwv dej. x yog qhov kev ncua deb ntawm lub hauv paus chiv keeb rau ib tug muab x tus nqi lub 2A sin (kx) ua ib tug tas li. 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. Ib qho kev sib haum xeeb yog ib qho ntawm cov lej sib npaug ntawm qhov zaus. Qhov tseem ceeb zaus (f) yog lub npe hu ua thawj harmonic, thiab 2f yog hu ua thib ob harmonic, thiab hais txog. Ib qho txiaj ntsig zoo ntawm kev sib haum xeeb yog Fourier tsom xam. Hauv kev tsom xam Fourier, txhua lub sijhawm ua haujlwm tuaj yeem tsim tau siv cov kev sib raug zoo ntawm cov nthwv dej yooj yim xws li sine yoj.
Yuav ua li cas yog Overtone?
Overtone txhais tau tias yog txhua zaus muaj tus nqi loj dua li qhov tseem ceeb ntawm qhov system. Thaum ib qho overtone ua ke nrog cov zaus zaus, nws yog hu ua ib feem. Lub harmonic yog xws li ib feem uas muaj ib tug integer multiplication ntawm lub hauv paus. Xws li ib feem yog tsim nyob rau hauv txhua yam twj paj nruag. Cov ntu no yog vim li cas txhua qhov cuab yeej suab paj nruag muaj nws lub suab sib txawv. Yog tias cov twj paj nruag tsim cov kev sib haum xeeb dawb huv, txhua yam ntawm cov cuab yeej no yuav zoo ib yam. Nyob rau hauv naming lub overtones, lub thib ob harmonic yog lub npe hu ua thawj overtone thiab lwm yam.
Dab tsi yog qhov txawv ntawm overtone thiab harmonic?
• Harmonics yog qhov sib npaug ntawm qhov sib npaug ntawm qhov tseem ceeb, tab sis overtones tuaj yeem coj tus nqi siab dua qhov zaus.
• Lub hauv paus zaus nws tus kheej raug suav hais tias yog thawj qhov sib haum xeeb, tab sis nws tsis raug cais raws li kev tshaj tawm. Tsis yog tag nrho cov overtones yog nyob ruaj ruaj nthwv dej. Tsuas yog cov overtones sib piv cov zaus ntawm cov harmonics ua raws li cov nthwv dej nyob ruaj khov. Tag nrho cov harmonics yog nyob ruaj ruaj nthwv dej.
