fightforever
Newbie level 2
- Joined
- Jul 25, 2009
- Messages
- 2
- Helped
- 0
- Reputation
- 0
- Reaction score
- 0
- Trophy points
- 1,281
- Location
- ChangSha,China
- Activity points
- 1,296
Hello Everyone,Recently I am debugging the DDR3 SDRAM controller, and get some waveforms which probed by TEK 50Gsps Oscilliscope(Fig.1)
In Fig.1(up) Eye Diagram,the orange eye is DQS, green eye is DQ; In Fig.1(down), the yellow line is DQS,the purple line is DQ.
My question is about the DQ signal: why does it go obviously slow when it reaches 926mv(position -0.5ns eye diagram)? why not the waveform like the following picture(fig.2)?
does the power cause this?
the DQ line trace is like the Fig.3
In Fig.1(up) Eye Diagram,the orange eye is DQS, green eye is DQ; In Fig.1(down), the yellow line is DQS,the purple line is DQ.
My question is about the DQ signal: why does it go obviously slow when it reaches 926mv(position -0.5ns eye diagram)? why not the waveform like the following picture(fig.2)?
does the power cause this?
the DQ line trace is like the Fig.3