用matlab对象进行数字基带调制解调（M-DPSK）

旧言虐心

1. <font face="Times New Roman">%% 仿真实现基带M-DPSK调制与解调
   
2. %% 利用Matlab modem object
   
3. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   
4. %   h = modem.dpskmod(property1, value1, ...)
   
5. %   h = modem.dpskmod(DPSKdemod_object)
   
6. %   h = modem.dpskmod(DPSKdemod_object, property1,value1, ...)
   
7. %   h = modem.dpskmod
   
8. %   if you have creat an object h for DPSK modulate, then the method
   
9. %   'modulate' can be used to modulate your signal x such as:
   
10. %   y = modulate(h, x)
    
11. %   and demodulation method need to creat an object
    
12. %   h = modem.dpskdemod(property1, value1, ...)
    
13. %   h = modem.dpskdemod(DPSKmod_object)
    
14. %   h = modem.dpskdemod(DPSKmod_object, property1,value1, ...)
    
15. %   h = modem.dpskdemod
    
16. %   if you have creat an object h for DPSK demodulate, then the method
    
17. %   'demodulate' can be used such as
    
18. %   y = demodulate(h, x)
    
19. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    
20. 
    
21. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    
22. clc
    
23. clear all
    
24. close all hidden
    
25. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    
26. 
    
27. M = 4;                   % The order for modulate of DPSK
    
28. nPacket = 5000;           % The signal length
    
29. x = randint(nPacket,1,M); % Signal for modulate
    
30. 
    
31. h = modem.dpskmod('M',M);      % Creat an object of DPSK modulation
    
32. y = modulate(h,x);        % modulate x get y
    
33. scatterplot(y);
    
34. yn = awgn(y,15,'measured'); % Pass the gauss channel with SNR=15dB
    
35. scatterplot(yn);
    
36. reset(h);                     
    
37. h = modem.dpskdemod('M',M);
    
38. z = demodulate(h,yn);
    
39. [num,rt]= symerr(x,z)
    
40. 
    
41. %% Process rectanglar pulse shaping
    
42. Nsamp = 4;               % Oversampling rate
    
43. ypulse = rectpulse(y,Nsamp);
    
44. ynoisy = awgn(ypulse,15,'measured');
    
45. ydownsamp = intdump(ynoisy,Nsamp);
    
46. scatterplot(ydownsamp);
    
47. reset(h);
    
48. h = modem.dpskdemod('M',M);
    
49. z = demodulate(h,ydownsamp);
    
50. [num,rt]= symerr(x,z)</font>

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转自：http://blog.sina.com.cn/s/blog_5def5a660100j3b9.html