low.m

滤波器的设计以及零极点对应频率响应分析

function Hd = low
%LOW Returns a discrete-time filter object.

%
% M-File generated by MATLAB(R) 7.1 and the Signal Processing Toolbox 6.4.
%
% Generated on: 08-Dec-2008 10:46:34
%

% Equiripple Lowpass filter designed using the FIRPM function.

% All frequency values are in Hz.
Fs = 1000;  % Sampling Frequency

N     = 10;  % Order
Fpass = 40;  % Passband Frequency
Fstop = 50;  % Stopband Frequency
Wpass = 1;   % Passband Weight
Wstop = 1;   % Stopband Weight
dens  = 20;  % Density Factor

% Calculate the coefficients using the FIRPM function.
b  = firpm(N, [0 Fpass Fstop Fs/2]/(Fs/2), [1 1 0 0], [Wpass Wstop], ...
           {dens});
Hd = b;


% [EOF]