问如何使用matlab系统函数cfirpm设计设定的频率响应滤波器？

clc
clear
S = load('演示曲线—全频.txt');
n = 128;
t=0:1:n-1;
f=t./n;

w = S;
b = cfirpm(n,f,@fresp,w,'even');
b = b(1:n/2);
fvtool(b);

function [dh,dw]=fresp(n,f,gf,w)

x1 = w(:,1); %频率 hz
x2 = w(:,2); %幅度值 db
x3 = w(:,3); %相位 度

% x1=[0;x1];
% x2=[0;x2];
% x3=[0;x3];

FS = 48000; %采样频率

x1_f = x1./(FS/2);
x2_a = power(10, x2 ./ 20);

x2_p = unwrap(x3);

a3 = interp1(x1_f,x2_a,gf,'spline'); % 幅度插值
p3 = interp1(x1_f,x2_p,gf,'spline'); % 相位插值

a3(1) = 0; 
p3 = p3*pi/180;

subplot(2,1,1);
plot(gf,a3); 
subplot(2,1,2);
plot(gf,p3); 

dh = 2*a3.* exp(-1i*p3);
dw=ones(length(gf),1);  

end