How does FIrpm work?
firpm designs a linear-phase FIR filter using the Parks-McClellan algorithm [2]. The Parks-McClellan algorithm uses the Remez exchange algorithm and Chebyshev approximation theory to design filters with an optimal fit between the desired and actual frequency responses.
What is firpm in matlab?
b = firpm( n , f , a ) returns row vector b containing the n+1 coefficients of an order- n FIR filter. The frequency and amplitude characteristics of the resulting filter match those given by vectors f and a .
What is extremal frequencies?
The extremal frequencies are the maximum and minimum points in the stop and pass bands. The stop band ripple is the lower portion of ripples on the bottom right of the plot and the pass band ripple is the upper portion of the ripples on the top left of the plot.