Transformasi Fourier
dan invers tranformasi Fourier adalah;
dimana:
t Boxcar function
t General boxcar function
adalah Transient function
dimana:
Delta Dirac function
Cossinus function
Sinus function
Constan function
Gaussian function
n Note: Fourier transforms Gaussian function
Note: Fourier transforms Gaussian function
Note: Fourier transforms Gaussian function
Note: Fourier transforms Gaussian function
Note: Fourier transforms Gaussian function
Note: Fourier transforms Gaussian function
Note: Fourier transforms Gaussian function
t t-1/2T T+1/2T
Time frequency window of the windowing Fourier transforms.
Non Stationary signals GaussianWindow Robi Polikar, The Wavelet Tutorial,
STFT with a = 0.01 (narrowest window) Well separated in timeWell separated in time Peaks correspond to a band of frequenciesPeaks correspond to a band of frequencies Robi Polikar, The Wavelet Tutorial,
STFT with a = (3rd widest window) Time resolution is becoming poorerTime resolution is becoming poorer Frequency resolution is improvingFrequency resolution is improving Robi Polikar, The Wavelet Tutorial,
STFT with a = (widest window) Terrible time resolutionTerrible time resolution Excellent frequency resolutionExcellent frequency resolution Robi Polikar, The Wavelet Tutorial,
A B
TIME·CONVOLUTION THEOREM
CORRELATION THEOREM
window
Blackman–Nuttall window