Low Pass FIR Filter, Comparison of Dolph Chebyshev and Hamming/Blackman/Blackman-Harris Windows.

Cuthbert Nyack
How does the performance of the Dolph-Chebyshev window perform with respect to transition bandwidth and stop band attenuation with the Hamming, Blackman and Blackman-Harris window.

Fn = 0/1/2 compares the Dolph-Chebyshev with the Hamming/Blackman/Blackman-Harris window.
The window functions, impulse response and frequency response of LP filters using the 2 windows are compared in the following applet.
By adjusting the variable parameters, it can be seen that the 2 windows can produce very similar filters.
The following is for comparing the transition bands:stop band attenuation.
eg parameters (83, 0.15, 2.36:2.27, NA, 0, -44, -46, 198, 257, 2) compares the Dolph-Chebyshev with the Hamming window.
eg parameters (83, 0.15, 3.76:3.16, NA, 1, -60, -70, 189, 273, 2) compares the Dolph-Chebyshev with the Blackman window.
eg parameters (83, 0.15, 5.26:4.82, NA, 2, -87, -94, 182, 293, 2) compares the Dolph-Chebyshev with the Blackman-Harris window.
Since the value of g required for the same stop band attenuation is less than the value required for fitting the transition band, it also means that for the same stop band attenuation, the Chebyshev window gives a narrower transition bandwidth than either of the 3 windows used here.



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COPYRIGHT 2008 Cuthbert Nyack.