anaask.m

来自「经典数字信号处理滤波器的源代码 重点是利用巴特沃斯模拟滤波器转而设计其它数字滤」· M 代码 · 共 48 行

function [y,am]=anaask(N,Ncomp,f0);
%ANAASK	Amplitude Shift Keying (ASK) signal.
% 	[Y,AM]=ANAASK(N,NCOMP,F0) returns a complex amplitude
%	modulated signal of normalized frequency F0, with a uniformly
%	distributed random amplitude. 
% 	Such signal is only 'quasi'-analytic.
%	
%	N     : number of points
%	NCOMP : number of points of each component (default: N/5)
% 	F0    : normalized frequency.              (default: 0.25)
% 	Y     : signal
% 	AM    : resulting amplitude modulation     (optional).
%
%	Example :
%	 [signal,am]=anaask(512,64,0.05); clf; figure(gcf);
%  	 subplot(211); plot(real(signal)); subplot(212); plot(am);
%
%	See also ANAFSK, ANABPSK, ANAQPSK.

%	O. Lemoine - October 1995
%	Copyright (c) 1996 by CNRS (France).
%
%	------------------- CONFIDENTIAL PROGRAM -------------------- 
%	This program can not be used without the authorization of its
%	author(s). For any comment or bug report, please send e-mail to 
%	[e-mail] 

if (nargin == 0),
 error('The number of parameters must be at least 1.');
elseif (nargin == 1),
 Ncomp=round(N/5); f0=0.25;
elseif (nargin == 2),
 f0=0.25;
end;

if (N <= 0),
 error('The signal length N must be strictly positive' );
elseif (f0<0)|(f0>0.5),
 error('f0 must be between 0 and 0.5');
end;

MatlabVersion=version; MatlabVersion=str2num(MatlabVersion(1));
if (MatlabVersion==4), rand('uniform'); end;

m=ceil(N/Ncomp); jumps=rand(m,1);
am=kron(jumps,ones(Ncomp,1)); am=am(1:N,1);
y=am.*fmconst(N,f0,1);