Windowing Continued


Hamming Window

The Hamming window multiplies the amplitude of the kth harmonic by the factor 0.54 + 0.46cos (pi × k/N).


The 12 Term Fourier Series of a Square Wave with a Hamming Window
N=12
Amplitude Frequency (rad/sec) Phase (degrees)
[0.54 + 0.46cos (pi × 1/12)] × 1 1 0
[0.54 + 0.46cos (pi × 3/12)] × 1/3 3 0
[0.54 + 0.46cos (pi × 5/12)] × 1/5 5 0
[0.54 + 0.46cos (pi × 7/12)] × 1/7 7 0
[0.54 + 0.46cos (pi × 9/12)] × 1/9 9 0
[0.54 + 0.46cos (pi × 11/12)] × 1/11 11 0


The Hamming window creates a smoother signal at the top of the square wave approximation. Add more harmonics creates an accurate approximation.


The 24 Term Fourier Series of a Square Wave with a Hamming Window
N=24
Amplitude Frequency (rad/sec) Phase (degrees)
[0.54 + 0.46cos (pi × 1/24)] × 1 1 0
[0.54 + 0.46cos (pi × 3/24)] × 1/3 3 0
: : :
: : :
[0.54 + 0.46cos (pi × 21/24)] × 1/21 21 0
[0.54 + 0.46cos (pi × 23/24)] × 1/23 23 0





This is the end of the presentation on Harmonic Phasors and the Fourier Series

Previous Page

Beginning of Presentation
Download related Matlab mfiles