Need help on FIR filter design

[smart_shaurya]

fir filter wc

Anybody please help me out in understanding the basics of designing a FIR filter...m not able to get it from Proakis and Manolakis...

plzzzzzzz.... m in urgent need...

 

[m_llaa]

check
DISCRETE-TIME SIGNSAL PROCESSING
by: A.V.Oppenheim, R.W.Schafer

 

[claudiocamera]

There are some methods to FIR design:

The most commom are: Windowing, Optimal method "Remez algorithm" and the frequency sampling method... Obviously there are other methods, but I just quote these three. ( they were wich I have used)

The first step is find a book and study the methods, wich book ? Oppenhein and Shafer, Proakis Ingle, Ifeachor and Jervis, SJ Mitra , Smith ... whatever , all of them ! After reading the principles ,I suggest you to take a look at the help of fir1 and fir2 Matlab function, then you will be ready to design some basics fir filter, after some practice you can implement your own c functions for each method if necessary , after studing some DSP programming you can go foward in the new field. Good luck and patience, you will need both if you really need to studying DSP programming.

 

[mehtesham]

see this:

 

[smart_shaurya]

claudiocamera is right...dis subject needs a lot of patience and demands a lots of time too...

 

[mimomod]

The simplest method to design an FIR filter is based on a technique called windowing. First we design an "ideal" filter (actually truncated ideal filter) with a certain length, e.g. an ideal low pass filter as the following matlab function does:

-------------------------------
function hd = ideal_lp(wc,M);
% Ideal LowPass filter computation
% --------------------------------
% [hd] = ideal_lp(wc,M)
% hd = ideal impulse response between 0 to M-1
% wc = cutoff frequency in radians
% M = length of the "ideal" filter
%
alpha = (M-1)/2;
n = [0:1M-1)];
m = n - alpha + eps; % add smallest number
%to avoid divide by zero
hd = sin(wc*m) ./ (pi*m);

----------------

The you multiply hd with a certain window function (hanning, hamming, kaiser, etc). See helps in matlab on the window functions. This window function will shape the transfer function of the FIR filter such that it has better properties than the original hd, e.g. lower side-lobes.

best

 

[ittefaq11]

chk DSp by ifeachor OR
dsp a comp based app by MITRA