There's probably no need to deinterlace your footage. If it's an animation from a graphics program (be it AE, Maya, Cinema 4d, whatever), the footage is most likely progressive. I'd guess it has to do with your sequence settings. What codec are you using for your timeline? DV is pretty bad with graphics. If you're dropping your footage into the DV timeline, then it's being rendered into the DV codec. So,if you're using DV, try switching to DVCPRO50 instead. You'll get crisper graphics, but what's going to happen is that you'll have to render out footage that's any other format (like DV) to DVCPRO50. But maybe try it as an experiment to see if that's the issue.