Crosstalk test system

[jjlee]

Hello,

I am trying to figure out a way to build crosstalk test system using the following HW/SW:

- 8- HP8133A: pulse gens (upto 8 driven lines)
- TDS8000 scope
- Labview 7.1
- Test vehicle (MoBo+daughter card)
- cables

Obviously, it would be necessary to "de-skew" and confirm both 1)"pulse timing" and 2)rise-time input to DUT. (before actually measure crosstalk)

The final goals are:
- To test both single-ended and differential channel signal(s)
- To have range of 1 to 8 driven lines
- To save instrument state for pulse and test settings
- To display crosstalk plots on scope or screen capture(?)
- To generate automatic crosstalk (NEXT/FEXT) report (for spreadsheet)

I would appreciate your advice/help, sharing similar experience for pointing me into the right direction.

Best regards,

[Shawn B.]

jjlee,

I have never built a system like the one you described, but I did find that there are instrument drivers for the HP8133A, and the TDS8000 on www.ni.com/idnet. They might at least provide a place for you to start, and if you run into problems along the way others might be able to help with the specific problems you encounter.

Shawn B.
National Instruments

[jjlee]

Thanks Shawn for your response.

I have a little more specific question.
In order to deskew two of the coaxial cable (using one scope channel), what should I use for a reference signal? I think it would be necessary to have a reference(or standard) signal that I can compare with other pulses from generators for deskewing.

The main objective here is to bring all(8) pulses into DUT with same timing, deskewed (including cable) and phase corrected.

Appreciate all your insights....

Best,

[Shawn B.]

jjlee,

I'm not really sure what you would want to use as a reference in this case. It will be difficult to ensure that all 8 signals will be brought into your DUT deskewed especially if you have to take into account the affect of different cable lengths. I'm not really an expert in this area, but maybe some others on the forum may have some suggestions.

Shawn B.
National Instruments

[jjlee]

The only thing that I can think of for deskewing is to make the triggering channel the reference and adjust the time such that all of these edges are aligned with each other and with the trigger point.

Does anyone have any good advice/suggestion?

Thanks,