f_filtnorm.asv

DSP程序 Matlab是一套用于科学工程计算的可视化高性能语言与软件环境。它集数值分析、矩阵运算、信号处理和图形显示于一体

function d = f_filtnorm (b,a,p);

%F_FILTNORM: Return L_p norm of filter H(z) = b(z)/a(z)
%
% Usage: d = f_filtnorm (b,a,p)
%
% Inputs: b = vector of length m+1 containing coefficients of 
%             numerator polynomial.
%         a = vector of length n+1 containing coefficients of 
%             denominator polynomial.
%         p = integer specifying norm type.  Use p = Inf for
%             the infinity norm
%
% Outputs: d = the L_p norm, ||h||_p
%

% Initialize

r = 500;

% Find impulse response

h = f_impul

n = length(a) - 1;
m = length(b) - 1;
N = floor((n+1)/2);
if  (m > n) | (abs(polyval(a,0)) < eps)
   fprintf ('\nFunction f_parallel requires that H(z) not have any poles at z = 0.\n')
   R_0 = 0;
   B = 0;
   A = 1;
   f_wait
   return
end

% Add pole at z = 0

if (m < n)
    b = [f_torow(b),zeros(n-m)];
    m = n;
end

% Sort poles and residues

[R,p,K] = residue (b,a);
[p,J] = sort(p);
R = R(J);
R = R ./ p;
R_0 = K - sum(R);

% Compute second-order blocks

k = 1;
for i = 1 : N
   if (mod(n,2) == 0) | (i < N)
      B(i,1:3) = [R(k)+R(k+1), -(R(k)*p(k+1)+R(k+1)*p(k)), 0];
      A(i,1:3) = [1, -(p(k)+p(k+1)), p(k)*p(k+1)];
      k = k + 2;
   else
      B(N,1:3) = [R(k), 0, 0];
      A(N,1:3) = [1, -p(k), 0];
      k = k + 1;
   end
end
%---------------------------------------------------------------------------------