2DPSK调制和解调系统的matlab仿真

Roof0102

function y=dpsk2()
- b. h0 f/ r3 h6 X: E) Lfs = 30000;
Time_Hold_On = 0.01;
# H( W5 T8 S5 s" L7 ~" q9 iNum_Unit = fs * Time_Hold_On;
High_Level = ones ( 1, Num_Unit );
Low_Level = zeros ( 1, Num_Unit );
w = 300;
& v9 \# ~' ]& G. o. F; p2 e5 Y1 MA = 1;
Sign_Set =randi(2,1,8)-1;
" G1 w/ ~2 ]4 o" f6 B0 ^. h! m8 tLenth_Of_Sign = length ( Sign_Set );
st = zeros ( 1, Num_Unit * Lenth_Of_Sign );
sign_orign = zeros ( 1, Num_Unit * Lenth_Of_Sign );
sign_result = zeros ( 1, Num_Unit * Lenth_Of_Sign );
2 d" T" X" K3 A0 e: P: D7 k9 ut = 0 : 1/fs : Time_Hold_On * Lenth_Of_Sign - 1/fs;
for I = 1 : Lenth_Of_Sign
+ D' P/ f9 l2 i, Uif Sign_Set(I) == 1
; d0 S6 X% g8 c+ r0 f" rsign_orign( (I-1)*Num_Unit + 1 : I*Num_Unit) = High_Level;
5 B% z: k2 C; j1 o( V. q: u! p( Velse
. `  ]" Y' u. d, Lsign_orign( (I-1)*Num_Unit + 1 : I*Num_Unit) = Low_Level;
# k0 Y2 X1 L2 |' C) `) v9 |end
# k. \2 ?7 h$ o) p( ^, `end
% p* b# @5 B: ]  j; a$ i; bfor I = 1 : Lenth_Of_Sign
if Sign_Set(I) == 1
9 ?3 E8 a) a" Q  v' t3 ist( (I-1)*Num_Unit + 1 : I*Num_Unit) = A * cos ( 2 * pi * w * t( (I-1)*Num_Unit + 1 : I*Num_Unit ) + ( pi / 2 ) );
5 U: o9 ~& I+ b4 S: Delse
st( (I-1)*Num_Unit + 1 : I*Num_Unit) = A * cos ( 2 * pi * w * t( (I-1)*Num_Unit + 1 : I*Num_Unit ) );
end
end

. @  ^; c4 G& Xfigure
; R# k' p% Y; L6 V1 G; w- B4 Lsubplot ( 2, 1, 1 )
plot(t, sign_orign);
axis( [ 0 , Time_Hold_On *( Lenth_Of_Sign + 1), - (A / 2), A + (A / 2) ] );
title ( '原始信号' );
2 y& d) o3 y, U2 ~  wgrid
( [3 n9 _2 \8 x, d
subplot ( 2, 1, 2 );
plot ( t, st );
axis( [ 0 , Time_Hold_On *( Lenth_Of_Sign + 1), - 3*(A / 2), 3*(A / 2) ] );
0 a+ Z% T( M7 {) t1 j; P" c  G+ ktitle ( '调制后的信号' );
grid
dt = st .* cos ( 2 * pi * w * t );
, J$ E7 L& R$ [/ W& ]# {. y
$ b" y0 t9 P  k3 `figure
subplot(2,1,1)
" L+ y. [$ g& f$ i4 zplot ( t, dt );
% t5 v9 o3 x  laxis( [ 0 , Time_Hold_On *( Lenth_Of_Sign + 1), - 3*(A / 2), 3*(A / 2) ] );
title ( '相乘后的波形' );
grid
[N,Wn] = buttord( 2*pi*50, 2*pi*150,3,25,'s'); %临界频率采用角频率表示
[b,a]=butter(N,Wn,'s');
[bz,az]=impinvar(b,a,fs); %映射为数字的

; V' |' u+ _* N+ ddt = filter(bz,az,dt);
$ i# r$ P' n  }$ `
subplot(2,1,2)
plot ( t, dt );
& [5 E2 l' G+ X0 X6 ~4 R- x3 m9 iaxis( [ 0 , Time_Hold_On *( Lenth_Of_Sign + 1), - 3*(A / 2), 3*(A / 2) ] );
; Q: d* k- ]# l: Q3 ^title ( '低通滤波后的波形' );
1 x4 f! L' u+ S( p) L0 d# T' ]grid
for I = 1 : Lenth_Of_Sign
if dt((2*I-1)*Num_Unit/2) < 0.25
sign_result( (I-1)*Num_Unit + 1 : I*Num_Unit) = High_Level;
0 K/ |8 N/ ~: F" v3 Q1 X/ w( @else
+ v$ u7 E' Z8 [8 o) S& psign_result( (I-1)*Num_Unit + 1 : I*Num_Unit) = Low_Level;
end
end
1 M9 t' E% z! ^" Z- [9 H
1 s+ b( ?8 c8 a* Z0 e' Rfigure
plot ( t, sign_result );
axis( [ 0 , Time_Hold_On *( Lenth_Of_Sign + 1), - 3*(A / 2), 3*(A / 2) ] );
. T5 |" d( \$ E$ B6 o3 K, v$ @9 ?8 vtitle ( '逆码变换后的波形' );
grid
# I) z3 M! J* T& E# }4 v

Blah

也就是可以直接对调制信号进行解调，理想信道下接收端信号与发送端信号完全相同

Jame33

再看看其他人是怎么说的
8 F, g4 ^& Z7 G( [. f- Z4 x

land

同问，求结果