2DPSK调制和解调系统的matlab仿真

Roof0102

function y=dpsk2()
fs = 30000;
+ N. a" z4 u  X2 n# Q" k1 jTime_Hold_On = 0.01;
Num_Unit = fs * Time_Hold_On;
High_Level = ones ( 1, Num_Unit );
Low_Level = zeros ( 1, Num_Unit );
w = 300;
" ~' d8 p# w+ z4 ~* `A = 1;
Sign_Set =randi(2,1,8)-1;
: v" x7 c$ a. k2 U+ mLenth_Of_Sign = length ( Sign_Set );
: g, A, H6 m9 O5 f- B# ast = 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 );
6 [3 B; I* K3 j3 K! @. Vt = 0 : 1/fs : Time_Hold_On * Lenth_Of_Sign - 1/fs;
$ x  P  j, S; Dfor I = 1 : Lenth_Of_Sign
& j3 m& B+ W; hif Sign_Set(I) == 1
- A; C$ h+ a% @' gsign_orign( (I-1)*Num_Unit + 1 : I*Num_Unit) = High_Level;
else
sign_orign( (I-1)*Num_Unit + 1 : I*Num_Unit) = Low_Level;
end
+ |' C8 [' v' J5 \end
7 I, l  g/ l: [' Dfor I = 1 : Lenth_Of_Sign
4 M; g; w; l0 i7 V5 l  Qif Sign_Set(I) == 1
7 Z, Z- c6 \! r  Mst( (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 m4 y6 O- K0 D* W; j, Xelse
! J& o( h" u9 tst( (I-1)*Num_Unit + 1 : I*Num_Unit) = A * cos ( 2 * pi * w * t( (I-1)*Num_Unit + 1 : I*Num_Unit ) );
7 _" r8 E( v# d# E6 w0 F+ qend
; B- ^0 m% x; l$ |1 P/ U) kend

figure
subplot ( 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' );
grid
7 [2 U/ d. ~0 f; W9 J1 a& w
subplot ( 2, 1, 2 );
- U9 Z& t: R4 uplot ( t, st );
. D/ y) O: ]) O9 kaxis( [ 0 , Time_Hold_On *( Lenth_Of_Sign + 1), - 3*(A / 2), 3*(A / 2) ] );
  t) N+ t4 c: y8 m% jtitle ( '调制后的信号' );
grid
dt = st .* cos ( 2 * pi * w * t );

figure
subplot(2,1,1)
plot ( t, dt );
axis( [ 0 , Time_Hold_On *( Lenth_Of_Sign + 1), - 3*(A / 2), 3*(A / 2) ] );
title ( '相乘后的波形' );
% F. |& h, g# ]5 k' Egrid
$ Z# T* h' J: v$ V1 A% E+ g' Q) y[N,Wn] = buttord( 2*pi*50, 2*pi*150,3,25,'s'); %临界频率采用角频率表示
' T0 ^' f& k0 W! A* r[b,a]=butter(N,Wn,'s');
! B& R9 E! P  `# q[bz,az]=impinvar(b,a,fs); %映射为数字的

dt = filter(bz,az,dt);
7 v% V1 A2 g- h/ z
subplot(2,1,2)
plot ( t, dt );
axis( [ 0 , Time_Hold_On *( Lenth_Of_Sign + 1), - 3*(A / 2), 3*(A / 2) ] );
title ( '低通滤波后的波形' );
7 S% Y4 u3 p1 N; p& x1 p+ e. R0 Igrid
for I = 1 : Lenth_Of_Sign
5 P$ u8 ^1 Q: Oif dt((2*I-1)*Num_Unit/2) < 0.25
* v# G( W5 n5 tsign_result( (I-1)*Num_Unit + 1 : I*Num_Unit) = High_Level;
$ }- v; N$ R  x$ O! Relse
4 G$ ]8 c/ r" g, ]8 rsign_result( (I-1)*Num_Unit + 1 : I*Num_Unit) = Low_Level;
end
6 K# Y; P  T, c& _3 u+ S! {! O# wend

: k9 p8 i0 ^& k. ]7 hfigure
' Y- R9 `9 L& M: G) f$ o3 z/ Qplot ( t, sign_result );
/ _5 a+ L: U5 P- d. D7 kaxis( [ 0 , Time_Hold_On *( Lenth_Of_Sign + 1), - 3*(A / 2), 3*(A / 2) ] );
title ( '逆码变换后的波形' );
* ^! D' Y+ Y/ w4 M! ?+ W( Tgrid
2 N: ]0 v0 l& K

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
) C  F! n, R: K* z

land

同问，求结果