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Nabila.
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March 10, 2021 at 7:13 am #69043
NabilaParticipantHello everyone
How can I make a simple Tx-fiber-Rx system with QAM modulation? From the existing sample in the optisystem using QAM followed by OFDM, can I use QAM modulation without OFDM? Then, How to measure the BER value? because when I try to make a simple system from QAM samples in https://optiwave.com/resources/applications-resources/optical-system-manchester-and-pam-codingdecodingdigital-modulation-qam/ the BER value is 0
Thank you
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March 10, 2021 at 7:24 am #69047
Ahmad AtiehModeratorDear Nabila,
please check the example (112Gbps SP-16QAM_B2B_subsystem with DSP_Investigating Power level calculation.osd) located at the following link in OptiSystem Example Library. This example is for 16QAM. However, it can be modified for other QAM levels. I hope this helps you.
When the BER is 0, the system performs perfectly. On the other hand, when BER is 1, the system is causing all bits to be erroneous.
C:\Users\USER NAME\Documents\OptiSystem 17.1 Samples\Advanced modulation systems\QAM systems\16 QAMRegards,
Ahmad-
March 10, 2021 at 7:55 am #69048NabilaParticipant
Thank you Mr. Ahmad
i already check the example. However, i want to know what the difference between the ber test set and the BER analyzer? can i change the ber test set to BER analyzer
i already check another advance modulation system example, all of them use ber test set
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March 10, 2021 at 9:41 am #69049Ahmad AtiehModerator
Dear Nabila,
you may check the theory used in each component by referring to the datasheet that can be accessed by right clicking on the component and selecting the component properties, then choosing Help.
The BER Test set is suitable for advanced modulation where you have decoding process at the receiver. The problem when using BER analyzer with decoded signal is the removal of all distortions that the pulses acquire through the transmission in the system.
Regards,
Ahmad -
March 22, 2021 at 10:05 am #69107NabilaParticipant
Hello Mr. Ahmad
Can i change the DSP and decision component in the example (112Gbps SP-16QAM_B2B_subsystem with DSP_Investigating Power level calculation.osd) with m-ary threshold? i try to make simple QAM system without OFDM and DSP component, but the BER results show a value of 0.5 or 0.49, what is the maximum value of BER that is good for a system? from what I know a good BER is 10 ^ -9 but the BER test value doesn’t seem to show the minimum BER value like in the BER analyzer -
March 22, 2021 at 12:54 pm #69108Ahmad AtiehModerator
Hello Nabila,
If I understand you correctly, you wanted to use the PAM receiver of the example (PAM fiber link w Threshold Detector.osd) with QAM system. Please note that the output of the DSP is a normalized output with QAM levels, not voltage as the PAM decision system. you could use the PAM decision if you split the I and Q signal and receive each separately.
Regards,
Ahmad -
March 22, 2021 at 1:41 pm #69110
vanaja 01Participant(Awaiting moderation)
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March 22, 2021 at 2:23 pm #69112NabilaParticipant
Dear, Mr. Ahmad Atieh
can I ask further? I’ve tried to contact you via emailThank you in advance
Regards, nabila
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