Suppose we want to design a low pass filter wp03pi ws 05pi

Suppose we want to design a low pass filter: wp=0.3pi; ws = 0.5pi; delta 1 = 0.001, delta z Write down the two Matlab commands that can be used to obtain such a filter when the sampling frequency of the system is 4000Hz.

Solution

FIR design functions in the Signal Processing ToolBox such as fir1 , firpm , firls are all capable of designing low pass filters with a specified order. The preferred function for low pass FIR filter design with a specified order is firceqrip. This function designs optimal equiripple lowpass/highpass with the specified passband and stopband ripple values and witha a specified passband edge frequency .

firgr is another such command that can design a filter that meets passband/stopband ripple constraints as well as specified transition width with the smallest possible filter order.

dsp.LowpassFilter is an alternative to using firceqrip or firgr.