- This topic has 6 replies, 4 voices, and was last updated 8 years, 11 months ago by
Ashu verma.
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July 8, 2015 at 11:10 am #22254
Fauza Khair
ParticipantDear All,
Please give me explanation about PRBS generator. We can set bit rate, order and number leading and trailing zeros in simulation.. How much (dBm) the power output of PRBS ? can we set the power output on PRBS ? or PRBS not have spesification the power amplitude ?
Thank
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July 8, 2015 at 11:18 am #22255
Alessandro Festa
ParticipantHi, that component is just a bit generator…so I don’t think that talking of dBm power for its output makes sense.
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July 8, 2015 at 11:42 am #22258
Fauza Khair
ParticipantThank Mr Alessandro Festa.. So, PRBS only generates the bit sequences, the value is true (1) or false (0), isn’t it ?
When the output PRBS is connected to QAM Sequence generator and then both of QAM Sequence outputs are connected to OFDM, we can measurement the electrical power in output of OFDM.. I have some difference power value if i use 4 QAM and 16 QAM. Please give me explanation, where the power in step could be present ? from QAM or OFDM ?
Thank you before,
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July 8, 2015 at 11:56 am #22259
Alessandro Festa
ParticipantYes, PRBS only generates 1 and 0.
It is better if you attach your design to comment the issue you are seeing. -
July 8, 2015 at 12:17 pm #22260
Fauza Khair
ParticipantThank you Mr Alessandro Festa..
Please try if bits per symbol = 2 or 4 bits.Regard,
Fauza
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July 8, 2015 at 3:39 pm #22270
gaganpreet Kaur
ParticipantAs per my knowledge by default system is set to 2 symbols per bit u can try and change the values scripted in ‘order’ and bit rate of PRBS
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July 10, 2015 at 10:19 am #22324
Ashu verma
ParticipantHello,Fauza khair
Alessandro said correct that PRBS is used to transmit random sequence of 0 & 1 and there is no power associated with PRBS. Now according to your second question about using 4QAM and 16QAM , that power change associated in OFDM system. According to my knowledge , 4QAM and 16QAM referred to 2 Bits/symbol and 4 Bits/ symbol respectively. 16QAM is different to 4QAM in the way that it is more bandwidth efficient and capable to transmit more data. However, using 16QAM increases noise level in OFDM system. I don’t think by using 4QAM or 16QAM there will be any change in power associate to it.
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