error(nargchk(3,7,nargin));								% 該函數定義一段隨機時間信號
	if nargin<4,
		mode = 'add';
			elseif ~strcmp(mode, 'per')&~strcmp(mode, 'add');
			error('invalid mode');
		end
	if nargin>5
		if ~strcmp(option, 'unif')&~strcmp(option, 'norm');
			error('invalid distribution option');
		end
		else
		option='unif';
	end
	if nargin>6
		v=version;
	if v(1) > 4
		rand('state', J);
		randn('state', J);
			else
				rand('seed', J);
				randn('seed', J);
			end
	end
t(1)=0;
	if strcmp(option, 'unif');
	if strcmp(mode, 'per');
		t=[1:N]./F_s+sqrt(6)*SM./F_s*(rand(1,N)-.5);
		t=t-t(1);
			elseif strcmp(mode, 'add');
				for ii=2:N,
					t(ii)=t(ii-1)+1./F_s+sqrt(12)*SM./F_s*(rand-.5);
				end
			end
			elseif strcmp(option, 'norm');
		if strcmp(mode, 'per');
			t=[1:N]./F_s+sqrt(2)*SM./2./F_s*(randn(1,N));
			t=t-t(1);
				elseif strcmp(mode, 'add');
					for ii=2:N,
					t(ii)=t(ii-1)+1./F_s+SM./F_s*(randn);
				end
		end
	end
if nargin>4
	t=t+t0;
end