Question

How to design FIR lowpass filter using matlab.

Note : Do not write matlab code. Only explain the steps of designing filter

Answer 1

1.)you can use the designfilt function and specify the input parameters for example), 'StopbandFrequency', 0.35, 'PassbandRipple', 0.25, StopbandAttenuation', 50, 'DesignMethod',"kaiserwin")

And you can use the fvtool to visualise the filter response.

lpFilt = designfilt('lowpassfir','PassbandFrequency',0.2, ...
'StopbandFrequency',0.35,'PassbandRipple',0.25, ...
'StopbandAttenuation',50,'DesignMethod','kaiserwin');
fvtool(lpFilt)

type =low pass filter--lowpassfir
% StopbandAttenuation-- =50dB
%window type =kaiser
% pass band frequency =0.2*pi
% stop band frequency =0.35*pi
%pass band ripple =0.25db

2.) another way is we can start by specifying the number of filter taps N = 31

specify the cut off frequency  

specify the sampling rate

specify the number of poles or transfer function

determine the filter order

use the fir2 function to define the filter

use the freqz to find the filter coefficients