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DS280DF810: DS280DF810- PRBS generator and FIR question

user6324245
Prodigy 80 points
Part Number: DS280DF810

Hello sir,

I have two question need your help.

1. 

Did DS280DF810 can be generate prbs without rx input signal?

I cannot find any info on datasheet and programmer;s guide

2. 

In the FIR filter, the datasheet and the programmer ’s guide describe that "(+) main-cursor, (-) pre-cursor, and (-) post-cursor will create a high-pass filter effect. When the sign of the pre- or post-cursor is the same as thesign of the main-cursor, this creates a low-pass filter response" .

Do you have additional information or documents may explain this?

Thanks and  Best Regards

  • 0
    TI__Mastermind 19235 points
    1. The DS280DF810 requires input signal for CDR to lock to in order to be able to generate PRBS pattern
    2. Refer to section 2 of the TI 25G Tx link optimization application note, per link below

    Regards,

    Rodrigo Natal

    HSSC Applications Engineer

  • 0 in reply to Rodrigo Natal
    Prodigy 80 points

    Hi Rodrigo,

    Thanks for your reply.

    But I still can't understand the FIR on high/low pass filter. in addition, I did not find similar information on the Internet. can you give me more description in this topical?

    Thanks and Best Regards

  • 0 in reply to user6324245
    TI__Mastermind 19235 points

    Equalization via FIR effectively applies de-emphasis via digital method.  The rising and falling edges of the waveform contain the high-frequency component of the signal while the low-frequency component resides in the non-transitions (or main cursor.) The FIR block acts as a high-pass filter when it boosts the high-frequency component by de-emphasizing the non-transition amplitude relative to amplitude right after the edge transition. The FIR block acts as a low pass filter when attenuating the high-frequency amplitude relative to the non-transition amplitude.

    I would suggest to read on FIR based equalization as well as analog de-emphasis. There is plenty of literature out there on these topics, from textbooks to papers and presentations prepared for high-speed communication industry committees and technical groups. 

  • 0 in reply to Rodrigo Natal
    Prodigy 80 points

    Hi Rodrigo,

    Many thank.

    Thanks and Best Regards