06-29-2016 12:31 AM
I generate differential signals out of a ML605 board from Virtex-6 GTX TX through FMC (got a little expansion board
to get SMA connectors).
Signal are ok on the scope.
I would like to feed a 50 ohms single-ended board with this differential signal.
Can you tell me if the following is ok and without "problems like getting the port toasted" :
I planned to
- first put "DC blocks" (capacitances) on-cable on both side of the differential
- then connect one side to the 50-ohms destination board input
- connect the other side to the ground of the destination board using a passthrough 50ohm SMA with a ground
output ( via a little chain).
I know that I may lose power but I can live with this ( signal will be amplify on the next stage ).
Thanks for your help.
06-29-2016 02:20 AM
06-29-2016 04:58 AM
This is for a kind of fast prototyping. If possible, I need to get a quick solution "pluggable" on SMA without
going in board design and fabrication ( these steps may be part of a future evolution of the project ).
The GTX produce 2Gbps signal.
I saw that there are some baluns that seems to support that speed with enough bandwidth to not distort
too much the signal. But they are quite expensive just for a prototype...
I also tried a little demo board for a differential ampli in single-ended on output , but the design of the board was
not appropriate for our needs.
Do you think that the solution I proposed with "DC blocks" and 50 ohms impedance on the "unused" side of
the differential output may damage the FPGA GTX port ?
Thanks again for your help.
07-03-2016 02:16 PM
Yes, that's the idea...
which single ended converters will work and how ?
I have a 2Gbps signal getting out through SMA ( got a FMC expansion card with SMA connectors for this purpose).
It work when I look at the scope.
What config will be the best to get high output directly in single-mode (if possible) and to adapt the output impedance ?
or if I get it differential (as I actually do ) how can I adapt it? Which single ended converters will fit well
this speedy signal?
Are there some design samples of outputs from Virtex-6 GTX that goes to something else than same or similar serdes ?