我在网上下载了几个程序，都运行不了，部分地方还看不懂，希望热心的高手门帮忙解决一下，谢谢了！

function qpskd(g,f)

%For more information, visit: www.matpic.com

%Modulation  QPSK

%Example: g is a binay vector; f is the carrier frequency.

%qpskd([1 0 1 1 0 0],2)

%Author. Diego Orlando Barrag醤 Guerrero

%diegokillemall@yahoo.com

%Loja (ECUADOR)

%See also:

%http://www.mathworks.com/matlabc ... 328&objectType=FILE

if nargin > 2

error('Too many input arguments');

elseif nargin==1

f=1;

end

if f<1;

error('Frequency must be bigger than 1');

end

%*-*-*-*-*-*

l=length(g);

r=l/2;

re=ceil(r);

val=re-r;

if val~=0;

error('Please insert a vector divisible for 2');

end

%*-*-*-*-*-*

t=0:2*pi/99:2*pi;

cp=[];sp=[];

mod=[];mod1=[];bit=[];

for n=1:2:length(g);

if g(n)==0 && g(n+1)==1;

die=sqrt(2)/2*ones(1,100);

die1=-sqrt(2)/2*ones(1,100);

se=[zeros(1,50) ones(1,50)];

elseif g(n)==0 && g(n+1)==0;

die=-sqrt(2)/2*ones(1,100);

die1=-sqrt(2)/2*ones(1,100);

se=[zeros(1,50) zeros(1,50)];

elseif g(n)==1 && g(n+1)==0;

die=-sqrt(2)/2*ones(1,100);

die1=sqrt(2)/2*ones(1,100);

se=[ones(1,50) zeros(1,50)];

elseif g(n)==1 && g(n+1)==1;

die=sqrt(2)/2*ones(1,100);

die1=sqrt(2)/2*ones(1,100);

se=[ones(1,50) ones(1,50)];

end

c=cos(f*t);

s=sin(f*t);

cp=[cp die];    %Amplitude cosino

sp=[sp die1];   %Amplitude sino

mod=[mod c];    %cosino carrier (Q)

mod1=[mod1 s];  %sino carrier   (I)

bit=[bit se];

end

bpsk=cp.*mod+sp.*mod1;

subplot(2,1,1);plot(bit,'LineWidth',1.5);grid on;

title('Binary Signal')

axis([0 50*length(g) -1.5 1.5]);

subplot(2,1,2);plot(bpsk,'LineWidth',1.5);grid on;

title('QPSK modulation')

axis([0 50*length(g) -1.5 1.5]);

运行时出现错误

??? Input argument "f" is undefined.

Error in ==> qpskd at 17

if f<1;

运行fsk的时候错误也一样

[本帖最后由 mooni 于 2009-4-1 17:08 编辑]