Re: Software Defined Radio on Xilinx Virtex 4


My translation of your original post was not off target, after all.

So here is my original answer:

It seems like you have the conversion of the analog sine wave to digital
(AD), and conversion back again (DA) working in both VHDL, and hardware,
yet you say you can not see anything on the oscilloscope? Just because
you hear something in the headphones may be cross-talk (just a
coincidence caused by a secondary path - parasitic coupling).

First, did you simulate the design? Does the simulation test bench work?

Second, are you able to input, and output static (unchanging) DC
voltages? This would be my first test, before I tried AC (sine waves).

If this is an issue with clocking (sampling), the DC will work, and then
the AC will have issues with frequency response (just guessing).

If the DC does not work, then I would use a logic analyzer (if it is
Xilinx, Chipscope(tm) is soft IP that may be part of your design, and
allows you to probe your digital signals inside the FPGA and see if they
are what you expect in the DC case).

Have fun,