function [x]=rspsp(damping,eqw,T)
%
% function [x]=rspsp(damping,eqw,T)
% Purpose: To calculate response spectrum of EQW
%    damping  阻尼比
%    eqw      地震波，地面加速度時程. 應具有兩列[t,u]
%             當 eqw 是向量時，則認為eqw(1)是時間間隔
%    T        向量，周期
%    x        計算結(jié)果，共三列，分別為位移，速度，加速度反應譜
% Note:    What we calulate are called Pseudo-velocity response 
%          spectrum and Pseudo-acceleration response spectrum.
% Author:  hjdwg@0451.com  98-11-25 15:57   
%

if nargin ~= 3 ,error('Nargin ~=3');end
[s1,s2]=size(eqw);
if s2>2,error('Illegal eqw format');end
if s2==2,
    u=eqw(:,2);
    t=eqw(:,1);
end
if s2==1,
    t=eqw(1)*(0:s1-2);
    u=eqw(2:s1,1);
end
x=zeros([length(T),3]);
w=2*pi./T;
for i=1:length(w)
SYS=tf(1,[1,2*damping*w(i),w(i)*w(i)]);
x(i,1)=max(abs(lsim(SYS,u,t)));
end
x(:,2)=x(:,1)*2*pi./T(:);
x(:,3)=x(:,2)*2*pi./T(:);
return