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Visitor jeromefievet
Visitor
2,914 Views
Registered: ‎02-02-2010

Viterbi decoder issue

Hi,

I have a problem with Logicore IP Viterbi Decoder

I used to use an ngo file generated more than ten years ago with ISE.
I have updated my project. Now, the IP is generated with same parameters but using Logicore IP Viterbi Decoder v9.0 under Vivado 2014.4.

The Viterbi Decoder component is inserted at the output of a 30 MBits demodulator, all running with a 100 MHz system clock.

I have two cases (old one vs new one):

  • Using the previous ngo generated IP, my bit error rate is null.
  • Updated version using Vivado works wrong with a residual bit error rate at 10-7…

I have inserted an ILA inside my design. I trigger when an error occurs at the output of the Viterbi decoder.

I export data inputs that created that error from the hardware to a Modelsim simulation of the same IP. The decoder output is correct.

 

I have no timing violations in reports.

 

Does anyone have an idea to help me debug this problem?

 

Thank you for you help

 

Jérôme

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