I want to know that why simulation takes more time to show it's signal constallation when the signal to noise ratio goes higher? I think it's not the issue of server/pc. Is anybody there to say about this ?

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Md Rafiqul Islam 2016-12-25

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关闭： MATLAB Answer Bot 2021-8-20

I am trying to get BER for different SNR(BPSK Modulation in AWGN Channel), suddenly I noticed this things.

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Hari Desanur 2016-12-29

Can you provide some more information such as the version of MATLAB you are using and also some reproduction code?

Md Rafiqul Islam 2017-1-1

QPSK_in_AWGN.mdl

version is R2016b. here I uploaded the file, just run it and change BER then you will see the time variation.

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Hari Desanur 2017-1-5

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The model is set up to run forever - stop time is "inf". The two Error Rate Calculation (ERC) blocks are set up to stop simulation when 1000 errors are collected or 1e6 samples are processed, whichever happens first.

In the default set up (Eb/No = 0), the first ERC block collects 1000 errors in ~6600 samples and stops the simulation. When you increase the Eb/No value, the error rate reduces significantly. Therefore none of the ERC blocks hit 1000 errors even after processing 1e6 samples.

So, in the default case, the simulation stops after processing ~6600 samples, while in the later case the simulation continues until 1e6 samples are processed. Hence, the longer simulation time.