Where to sample the output in BPSK demodulator using Matlab?

[anadrol]

iam having this problem in the desgin of bpsk demodulator , i tried both correlator and matched filter approachs and the output of them the same, the problem is i don't know where to sample the output. when i tried to sample it at symbol periods it gives me sometimes BER>=0.5,
please need ur help


please change the extension of the file to .m
thx in advance

 

[Mohamed El-Shimy]

matlab help output code

Hello,

I think to reduce the BER, you have to begin sampling your received signal at its maximum value. This will give the maximum SNR.

 

[anadrol]

bpsk sample synchronisation matlab code

can u explain more
i used the snr to be 12 db
what should i change
and tell me what u think of the output of the correlator

thx

Best regards
Yours Faithfuly
Ameer Mohamed

 

[Aya2002]

matched filter matlab tutorial

Hi Ameer Mohamed,
i can not see your upload, can you copy your code and past it here so i can see it, may be i can help you.

Regards
see my web site
Montadar Abas Taher

 

[ouardi]

matlab code correlator

it is easy if you use equivalent scheme in base band

it means, the channel will include : the transciver filter + the modulator + ..+ the real channel+ .. + the demodulator + the reciever filter + the matched filter .

for see the infect of noise for example, we apply the superposition principal. It means , we assume the all others blocs are perfect : modulation , synchronisation , ....

its very easy, you must generate random information 0 and 1
make the mapping 0----- -1
1------- +1
if the channel is ideal (not selective), the signal at the output of channel is the same, else , its the signal + the ISI InterSymbo Interference

add the gaussian noise

make decision, if the signal<0 --------- 0
signal > 0 ----------1

compute the BER

compare to error probability of the BPSK 1/2(erfc((E/N0)^0.5))


see more (Digital communication) PROAKIS

good luck

 

[ux]

mohamed el-shimy

iam having this problem in the desgin of bpsk demodulator , i tried both correlator and matched filter approachs and the output of them the same, the problem is i don't know where to sample the output. when i tried to sample it at symbol periods it gives me sometimes BER>=0.5,
please need ur help

Look at the useful simulink models attached in this topic: