How to design a FIR Filter

Hello, I am new to matlab. I want to design FIR,Butterworth and some RC filters in Matlab with GUIDE. Someone told me that I can design it using Signal Processing Toolbox. Is it possible to implement these filters without any toolboxes otherthan just matlab and GUIDE.

Answer 1

[Wayne King]

Yes, it is possible, but you will have to write a lot of code. The Signal Processing Toolbox (SPT) enables you to create these filters easily. Filter design code can be very complicated, so you will have to invest a lot of time to do it without SPT.

Answer 2

[Tina]

not sure about rc filter but FIR and butterworth filter can be designed by the help of built in function fir1,Filter.

b = fir1(48,wc);
freqz(b,1,512)

for butterworth you use butter(L).

n=%order of filter
fs=%sampling frequency
fc= %your corner frequency
wc=fc/(fs/2);%cuttoff freq of filter
b=fir1(n,wc,'low',butter(n+1);
[H,w] = freqz(b,1);
plot(w/pi,20*log(abs(H)))
title('butterfilter')

and you can design simple filter by

d=designfilt('lowpassfir','filterorder',n,'cutoffFrequency',fc,'samplerate',fs);
Filtered=filter(d,signal)%signal is the signal you wont to filter