function?[smod]=generate_mod_signal（typetotal_timefcfssymbol_rate）
%?total_time?:?length?of?signal?in?seconds
%?fc?:?carrier?frequency
%?fs?:?samplling?frequency
%?symbol_rate?:?symbol?rate
%?type?:?modulation?type
????if?fs?????????disp（‘error‘）;????
????end
????????
????alpha=0.5;
????ts=1/fs;
????T=1/symbol_rate;
????t=ts:ts:total_time;
????
????N=floor（total_time*fs）;
????
????a=0.85;?????????%?modulation?factor
????d=randn（1N）;
????[numden]=butter（50.01）;
????bs=filter（numdend）;
????bs=bs/max（abs（bs））;
????t=ts:ts:total_time;
????
????te=-T+2*ts:2*ts:T;
????g_t=sinc（te/T）.*cos（pi*alpha*te/T）./（1-（4*alpha*te/（2*T））.^2+eps）;
????
????
????switch?type
case?1??%?AM
????s=（1+a*bs）.*cos（2*pi*fc*t）;
????mod=1;
case?2????????%?AM-DSB
????s=bs.*cos（2*pi*fc*t）;
????mod=2;
case?3????????%?AM-LSB
????s=bs.*cos（2*pi*fc*t）+imag（hilbert（bs））.*sin（2*pi*fc*t）;
????mod=3;
case?4??????%?AM-USB
????s=bs.*cos（2*pi*fc*t）-imag（hilbert（bs））.*sin（2*pi*fc*t）;
????mod=4;??
case?5????%?FM
????k=0.2*fc;
????int_bs（1）=0;
????for?i=1:length（t）-1;
????????int_bs（i+1）=int_bs（i）+bs（i）*ts;
????end
????s=cos（2*pi*fc*t+2*pi*k*int_bs）;
????mod=5;
case?6?%?AM-FM-combined
????%?????k=0.02*fc;
????%?????int_bs（1）=0;
????%?????for?i=1:length（t）-1;
????%?????????int_bs（i+1）=int_bs（i）+bs（i）*ts;
????%?????end
????
????temps=amod（bsfcfs‘fm‘0.2*fc）;
????ms=hilbert（temps）.*bs;
????s=real（ms）;
????mod=6;??
case?7???%?2-ASK
????d=randint（1floor（total_time*symbol_rate）2）;
????dmap=modmap（dsymbol_ratefs‘ask‘）;
????g_tr=repmat（g_t1length（d））;
????s=dmap.*g_tr.*cos（2*pi*fc*t）;
????mod=7;
case?8??%?4-ASK
????d=randint（1floor（total_time*symbol_rate）4）;
????dmap=modmap（dsymbol_ratefs‘ask‘）;
????g_tr=repmat（g_t1length（d））;
????s=dmap.*g_tr.*cos（2*pi*fc*t）;
????mod=8;???
case?9??%?16-QAM
????d=randint（1floor（total_time*symbol_rate）16）;
????s_r=dmod（dfcsymbol_ratefs‘qask‘）;
????g_tr=repmat（g_t1length（d））;
????s=g_tr.*s_r;
????mod=9;
case?10?%?2-PSK
????d=randint（1floor（total_time*symbol_rate）2）;
????s_r=dmod（dfcsymbol_ratefs‘psk‘）;
????g_tr=repmat（g_t1length（d））;
????s=g_tr.*s_r;
????mod=10;
case?11%?4-PSK
????d=randint（1floor（total_time*symbol_rate）4）;
????s_r=dmod（dfcsymbol_ratefs‘psk‘）;
????g_tr=repmat（g_t1length（d））;
????s=g_tr.*s_r;
????mod=11;??
case?12?%?8-PSK
????d=randint（1floor（total_time*symbol_rate）8）;
????s_r=dmod（dfcsymbol_ratefs‘psk‘）;
????g_tr=repmat（g_t1length（d））;
????s=g_tr.*s_r;
????mod=12;?
case?13?%?2-FSK
????d=randint（1floor（total_time*symbol_rate）2）;
????s_r=dmod（dfcsymbol_ratefs‘fsk‘）;
????g_tr=repmat（g_t1length（d））;
????s=g_tr.*s_r;
????mod=13;?
case?14?%?4-FSK
????d=randint（1floor（total_time*symbol_rate）4）;
????s_r=dmod（dfcsymbol_ratefs‘fsk‘）;
????g_tr=repmat（g_t1length（d））;
????s=g_tr.*s_r;
????mod=14;?
case?15?%?MFSK
????d=randint（1floor（total_time*symbol_rate）2）;
?

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件???????3116??2006-05-09?09:37??generate_mod_signal.m

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?????????????????3334????????????????????2