I am experienced design engineer. This is one of my favorite interview questions related to high speed design - "why not DFE -only"? Just one line but you need to know lot of things to answer that.
@circuitimage
6 ай бұрын
Hi Sai, Thank you so much for your feedback. I agree with your favorite interview questions related to high-speed design - "why not DFE -only" :)
@ericcartman5396
Жыл бұрын
Great job! Thanks for taking time and effort to share your knowledge.
@circuitimage
Жыл бұрын
Hi Spaceboy, Nice to meet you. You're very welcome. Thank you for the feedback and I'm glad you liked it. 😀
@alterguy4327
2 жыл бұрын
You are doing god's work brother. Respect from India
@circuitimage
2 жыл бұрын
Thanks for the feedback and I'm glad to hear it from India.
@NaveenKumar-wt2kx
2 жыл бұрын
Hi, Excellent videos. Please post more videos Rx detection, resistor calibration, slicer calibration, CDR loops and IQ calibration
@circuitimage
2 жыл бұрын
Thanks for the feedback. I'll share those excellent topics you suggested.
@abhiruplahiri1
2 жыл бұрын
Very well explained and nice images as usual. Cheers.
@circuitimage
2 жыл бұрын
Thanks for the feedback.
@hrachya_khachatryan
Жыл бұрын
Hi, another very useful video :) One question. At 11:21 you provide loop delay formula. I understood that TFB comes for H1 (or H2), TSUM is the summer settling time, TCK_Q is the slicer decision time (looking to first tap, which is the critical one). Basically TCK_Q is determined from the clock edge to the slicer output reaching let's say 90% . However I don't understand what TSetup is, which you mention is sampler's setup time. As far as I know the clock and data are 90 degrees shifted with respect to each other. Is it possible that clock doesn't arrive exactly at 90 degrees shift and this creates additional delay which you denote as TSetup ? Thanks
@circuitimage
Жыл бұрын
Hi Hrachya, Thank you for the excellent question. Ideally, w/ the BB or MM CDR, that would be that clock should arrive exactly at 90 degrees. But, if the eye is not symmetric (on average), the BBPD (CDR) would make a shift slightly earlier or later. Similarly or more vulnerable in a MM (Baud-rate) CDR, the pulse response may cause the clock doesn't arrive exactly at 90 degrees shift. I hope those examples can provide insight into those subtleties.
@hrachya_khachatryan
Жыл бұрын
@@circuitimage Thanks a lot for useful info. So, in conclusion the TSetup term in the delay formula is because the clock possibly can arrive not exactly 90 degrees phase shifted ?
@circuitimage
Жыл бұрын
@@hrachya_khachatryan You're very welcome. That's correct.
@weiliwu7741
Жыл бұрын
Thanks for your video, I have one question about error propagation in DFE, even burst error. For this disadvantage, we usually use THP precoding in PAM-4 mode. But why we seldom use this technique in NRZ mode? Is this related to DFE?
@circuitimage
Жыл бұрын
Hi Weili, Nice to meet you and thanks for your excellent questions. You're correct. The PAM-4 has a much less margin (in eye width & eye height) than the NRZ; therefore, the precoding is necessary to mitigate the burst error, which is not very sensitive to NRZ in a DFE usage. You can refer to my other "why PAM4 & NRZ videos" to get more images of both signaling differences. 😉
Hi Johnny, 非常感謝您的良好回饋。是的我同意。即使殘餘 ISI 不同,自適應 DFE 也應該能夠校準到正確的係數並正確消除。所以,我沒有強調這個微妙之處。
@srinivaskalwad
Жыл бұрын
Very well explained the topics and good attention seeking images.
@circuitimage
Жыл бұрын
@Srinivas Kalwad Glad you liked it!
@sunkarasaigoutham
2 жыл бұрын
Great videos but a quick question, why is error propogation not a big deal?
@circuitimage
2 жыл бұрын
Thanks for the good question. The BER target is very small, e.g., < 1e-12 or 1e-15. Therefore, it's unlikely to be stuck from the error propagation if the DFE works in the beginning with a BER under the target.
@NaveenKumar-wt2kx
2 жыл бұрын
Thanks for the great videos, can you please share all these slides with me?
@circuitimage
Жыл бұрын
@Naveen Kumar Merry Christmas and Happy New Year! Thanks for the feedback and I'll provide an option for you.
@NaveenKumar-wt2kx
Жыл бұрын
@Circuit Image Thank you so much. Merry Christmas and Happy New Year, you too.
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