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3,741 Views
Registered: ‎11-24-2008

Does GTH TX work on RX recovered speed?

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Hello,

 

Can Ultrascale GTH TX work on RX recovered speed? Typically TX work with speed based on external reference clock but I have to

transmitt exactly same received data stream (that can have little difference like several ppm).

 

Thanks

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Moderator
Moderator
5,161 Views
Registered: ‎02-16-2010

Re: Does GTH TX work on RX recovered speed?

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In this type of use case, the recovered clock output from the GT is given as input to the external synthesizer for jitter cleanup. The output of this synthesizer is given as input to GT reference clock.
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Xilinx Employee
Xilinx Employee
3,719 Views
Registered: ‎02-14-2014

Re: Does GTH TX work on RX recovered speed?

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Hello @sergey_checkrygin,

 

Yes this is possible to make GTH TX work on RXOUTCLK (recovered from CDR) . If there are ppm differences between TX and RX reference clocks, then you need to use TX buffer in order to take care of this difference.

Regards,
Ashish
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3,714 Views
Registered: ‎11-24-2008

Re: Does GTH TX work on RX recovered speed?

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Hello Ashish,

 

Thanks for reply.

Could you describe scheme (or provide a reference) for implement it (TX work at RX CDR clock)?

 

BR, Serge

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Moderator
Moderator
5,162 Views
Registered: ‎02-16-2010

Re: Does GTH TX work on RX recovered speed?

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In this type of use case, the recovered clock output from the GT is given as input to the external synthesizer for jitter cleanup. The output of this synthesizer is given as input to GT reference clock.
------------------------------------------------------------------------------
Don't forget to reply, give kudo and accept as solution
------------------------------------------------------------------------------

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3,685 Views
Registered: ‎11-24-2008

Re: Does GTH TX work on RX recovered speed?

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Does use OBUFDS_GTE3(4) - is only one correct way to feed external clock synthesizer/cleaner by MGT RX CDR clock?

What about route out MGT RX CDR via FPGA fabric and general IO?

Moreover, is possible to use MGT RX CDR clock as reference for MGT TX without external synthesizer/jitter_cleaner if CDR clock route out via  OBUFDS_GTE3(4) for OTU2 application?

 

BR, Serge

 

 

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Visitor kgadeyne
Visitor
2,827 Views
Registered: ‎07-13-2011

Re: Does GTH TX work on RX recovered speed?

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If you really have to go without an external jitter cleaner, have you considered using Xilinx PIcXO?

 You'll find a lot of info with that search term on the support site.

 

K.

 

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