Scilab Function
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nfilter - finite impulse response filter

Module

• Modnum

Description

That function is a bench of finite impulse response (FIR) filters. For each filters, the same impulse response (h) is used. It can be used both with double or int32 entries.
The computation used here is the discrete convolution.

Calling Sequence

[y[,z]]=nfilter(u,h[,z])

Parameters

• u : The inputs to be filtered. Matrices of size n,m are interpreted as m vectors of size n.
• h : Vector of impulse response (of size nbcoef).
• y : Filtered outputs.
• z : States of filters (m vectors of size nbcoef).

Example

//3 vectors of 200 symbols
y = genint(200,3,1,2);
//Q-PSK modulation
[yi,yq] = modpsk(y,4);
//up-sample by 8
yi_s = upsmpl(yi,8,1);
yq_s = upsmpl(yq,8,1);
//compute Raised Cosine impulse
//roll-off=0.35, length 128
pulse = filter_tap(2,128,8,0.35,1);
//filtering 3 vectors of I/Q components
i = nfilter(yi_s,pulse');
q = nfilter(yq_s,pulse');
//plot eye diagram of the first vector of I
plot2d(matrix(i(:,1),16,100));

Used function(s)

• nfilter_c_rout - finite impulse response filter by discrete time convolution method computational routine (Low level routine)

See Also

• RIFGEN_f

Authors

A. Layec