Why TXFFE?

[@andywestwood2972]

I have been looking for a way to help my colleagues understand FFE/DFE and how they operate. Your tutorials are excellent, clear with very helpful visuals and examples of real device issues. Thank you for this entire series, sir.

[@circuitimage]

Hi Andy, You're very welcome. Nice to meet you. I'm glad that's helpful. 😊

[@jianggu-ml3kx]

I am a pll designer for ten years, and I want to learn serdes design. Your description is very clear and easy to understand. Very helpful. Thanks

[@circuitimage]

Hi Jiang, nice to meet you and I'm glad that helped you. 😀

[@rushikeshnavghare3373]

Very detailed and on point explanation. Thank you.

[@suryanarayanpanda3610]

Great.....can you please explain a bit more on how you choose the coefficient values of Pre and Post cursor taps. And 2nd doubt is can we see any case where you keep both the coefficient to be positive and in that case if the transition parts will have higher swing or lower ?

[@circuitimage]

Hi Surya, Thank you so much for the good questions. I have comments below. Great.....can you please explain a bit more on how you choose the coefficient values of Pre and Post cursor taps. [CC] I did the a single-pulse response to figure out the coefficients of Pre and Post cursor, respectively. And 2nd doubt is can we see any case where you keep both the coefficient to be positive and in that case if the transition parts will have higher swing or lower ? [CC] Yes, that's possible. We only focus on the data parts, but the transition parts could have a higher swing or lower due to the reflection. Thanks, CC

[@ronidadon1]

Great video! Can you explain how you calculate the "zero forcing" TXFFE coefficients for a given channel response based on the received waveform

[@circuitimage]

Hi Roni, Nice to meet you and thanks for the good questions. To get the coefficients of all the precursor or the post-cursor ISI, we could just send a pulse response to a lossy channel and calculate the ratio between the main cursor (peak) w.r.t. the pre-cursor or the post-cursor amplitude.

[@shaikjohnshaida4009]

Nice explanation. Can you please tell any text book ? we can refer regarding high speed SERDES blocks

[@circuitimage]

Hi Shaik, you can refer Prof. Razavi's book: www.amazon.com/Design-Integrated-Circuits-Optical-Communications/dp/0072822589

[@madhooz]

Your videos are really helpful in understanding the signal flow in both frequency and time domain....

[@circuitimage]

Thanks for the feedback. Let me know if you need more in other images. :)

[@user-ot9ew9tp1c]

有聽到一種說法是TX FFE增益會小於1，因此只能叫de-emphasis不能叫pre-emphasis，不知道這樣是否正確，還是這兩種說法只是代表高頻和低頻的相對比較，並沒有強調增益的部分。

[@circuitimage]

Hi Johnny, 感謝你提出的好問題。您的理解是正確的。整體最大擺幅固定；因此，我們可以減少低頻擺幅，但將高頻擺幅保持在整體最大擺幅內!

[@parkerm6514]

I am a new postgraduate that recently step on the path of learning SerDes. This video series will truly help a lot.🎉🎉

[@circuitimage]

Hi Parker, nice to mee you. I'm glad that helps. Feel free to let me know what else you'd like to learn. :)

[@rezvanmohammadrezaee6121]

Thanks for a great video! It really helped me understand all the effects that FFE equalization can have on the channel response.

[@circuitimage]

You're very welcome!

[@ssayank]

Great Videos. Concepts of FFE are explained very clearly.

[@circuitimage]

Thanks for the feedback.

[@yifengguo-t9u]

Why is it said that a coefficient greater than or less than 0 means there is no requirement?

[@shadyEA60]

Thanks for the good video. is there a difference between pre-emphasis and de-emphasis terms?

[@circuitimage]

Hi Shadi, Good question. Thanks! The short answer is no, which is just different term people called it. Thanks, CC

[@ashwinikumarib2596]

Thankyou so much for these series. Very helpful

[@circuitimage]

Hi Ashwini, nice to meet you and I'm glad I can help you. Please let me know if you have additional questions or feedback. :)😃

[@abhiruplahiri1]

Really like the images to present the core ideas. Cheers.

[@circuitimage]

Thanks for the feedback.

[@ZanZ-qi6wz]

Thanks for the Great Video, It helps me understand better.

[@circuitimage]

Hi Zan, You're very welcome and I'm glad it helps you understand better. 😀

[@xiaoyangwang1625]

Thanks a lot for this helpful video! One question, can you give some explanation of the pre-cursor and post-cursor? My understanding is that they are showing how much the distortion is before and after the symbol, the smaller the better, not sure is this is correct. Thanks.

[@circuitimage]

Hi Eren, nice to meet you and thank you for the feedback. You are correct. The pre-cursor and post-cursor are the distortions before and after the symbol, respectively. To have smaller distortions, the smaller the better. :)

[@xiaoyangwang1625]

@@circuitimage Got it, thanks for the clarification!

[@circuitimage]

@@xiaoyangwang1625 You're very welcome and I'm glad that helps. 😃

[@hgl9590]

什么样的应用场景会存在long-run pattern? long-run pattern 指的是Tx 在一段时间内只发送0或1吗

[@circuitimage]

Hi HG, Nice to mee you and thank you for the good feedback. The TX could send 0 or 1 with 50% probablity if there's no encoding. If yes, that would depend on the coding methodology. FYI: kzbin.info/www/bejne/qIXClap3qrJ7h6ssi=DDLeUKTDzNP9UcAw Thanks, CC

[@changhsiao2132]

Great explanations, Thanks!

[@circuitimage]

Circuit Image 2 days ago Thanks for the feedback and I'm glad you like it. :)

[@diwakarramamurthy6428]

Thanks . Great Video and Explanation

[@circuitimage]

Thanks for the feedback and I'm glad you like it.