QPSK modulation, sequence lenght, samples per bit
Hello
I’m making ROF with qpsk modulation. I need 2 Mb/s and 1800 MHz so I set bit rate to 2 Mb/s symbol rate to 1 Mb/s but I don’t know how to set sequence length and samples per bit. I have been trying bunch of different sets but I have never reached 1800 MHz. My carrier is always below 300 MHz. Could you give me advice how to properly set those parameters ? I have attached my project.
Best regards
Responses (9):
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Hello
I’m making ROF with qpsk modulation. I need 2 Mb/s and 1800 MHz so I set bit rate to 2 Mb/s symbol rate to 1 Mb/s but I don’t know how to set sequence length and samples per bit. I have been trying bunch of different sets but I have never reached 1800 MHz. My carrier is always below 300 MHz. Could you give me advice how to properly set those parameters ? I have attached my project.
Best regards
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Hi Maciej, what do you mean by “I have never reached 1800MHz”?
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Hello
The highest frequency that I can get is about 300 MHz.
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After setting bitrate and simbol rate, go to “Simulation Window” and choose “Set sample rate”. Now you can change the sample rate to >1800MHz.
Does this answer your question?
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Yes, thanks 🙂 but I have one more problem. I have been trying measure BER but my BER analyser doesn’t work. Could you help me in that problem ?
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I will have a look at your file once in office…what do you mean exactly by “does not work”?
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I think that my BER is too good. I have attached my project.
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You are arriving at the receiver with high power and high OSNR…why would you expect a worse BER? I ran the simulation and it gives 1E-66
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Yes but I set optical fiber length to 160 km. I got very bad graph of constellation and very good BER (about 10^-30).
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This is my graph showing dependency between length and BER.
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