Amplitude thiab theem Txhua tus lej hauv qhov tshwm sim ntawm FFT yog tus lej. Koj tuaj yeem xav txog qhov no yog qhov encoding ntawm ob qho tib si amplitude thiab theem ntawm txhua qhov sib txuas.
Puas Fourier hloov tau txoj kev nyuaj?
In the complex Fourier transform, two & are arrays X[k] x[n] X[k] of complex numbers … Thib ob, Fourier tiag tiag tsuas yog cuam tshuam nrog zoo zaus. Ntawd yog, qhov ntsuas qhov ntsuas zaus, k, tsuas yog khiav ntawm 0 mus rau N / 2. Nyob rau hauv kev sib piv, qhov complex Fourier transform muaj xws li ob qho tib si zoo thiab tsis zoo frequencies.
Vim li cas FFT complex tso zis?
Cov lej nyuaj hauv FFT qhov txiaj ntsig tsuas yog 2 tus lej tiag tiag, uas yog ob qho tib si yuav tsum muab rau koj 2D kev tswj hwm ntawm cov txiaj ntsig vector uas muaj ob qho tib si ntev thiab ib qho. lub kaum sab xis (los yog qhov loj thiab ib theem).
Dab tsi yog qhov kev xav ntawm FFT?
Ib FFT yog ib feem ntawm theem kev tshuaj ntsuam, thaum IFFT yog ib feem ntawm theem kev sib txuas. Txoj kev ifft pov tseg qhov kev xav ntawm qhov rov qab FFT txoj kev tso tawm. Rau cov tswv yim tiag tiag, qhov kev xav yog zero, hauv kev xav.
Yuav ua li cas muaj pes tsawg tus lej sib npaug hauv FFT?
Peb pom tias rau txhua tus nqi ntawm k, kev suav ncaj qha ntawm X(k) suav nrog N complex multiplications (4N tiag multiplications) thiab N-1 complex ntxiv (4N-2 tiag tiag ntxiv). Yog li ntawd, txhawm rau suav tag nrho N qhov tseem ceeb ntawm DFT yuav tsum tau N 2ntau ntau thiab N 2 -N complex ntxiv.
