Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Wireline High-Speed TX Pre-emphasis FIR Filter Response.

Status
Not open for further replies.

JohnLai

Junior Member level 3
Joined
Sep 27, 2008
Messages
25
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,481
Hello, Folks,

An online tutorial (Intel SI Fundamentals Short Course - Equalization) shows an TX Pre-emphasis FIR filter has such frequency response:

Picture1.png

The green line in the above figure shows that there is a dip at 6.4GHz for the 6.4Gb/s data transmission. I do not understand why there is such a dip at 6.4GHz since this is exactly what the frequency components are needed for transmitted data. I am also expecting the pre-emphasis should be a high-pass filter like a passive CTLE due to the low-pass characteristics for wireline channels.

Could someone please explain it to me.

Thank you.
 

Hi

that's the sampling frequency or delay time. From FFT of power spectrum, no power for that point.
you can get examples by check RZ and NRZ FFT

Hello, Folks,

An online tutorial (Intel SI Fundamentals Short Course - Equalization) shows an TX Pre-emphasis FIR filter has such frequency response:

View attachment 87276

The green line in the above figure shows that there is a dip at 6.4GHz for the 6.4Gb/s data transmission. I do not understand why there is such a dip at 6.4GHz since this is exactly what the frequency components are needed for transmitted data. I am also expecting the pre-emphasis should be a high-pass filter like a passive CTLE due to the low-pass characteristics for wireline channels.

Could someone please explain it to me.

Thank you.
 
alvays,

Thank you for pointing that out. That makes sense to me.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top