Black Screen Problem with DVD Recorders


I just recently purchased a Sony DVD Recorder (Model RDR-GX300). This is my first DVD Recorder purchase. I noticed that on black screens the recorder has a problem picking it up. I can see pixels floating around between black and dark grey. It seems like the recorder is having a problem processing a black screen. I notice this on digital programs from Comcast Digital Cable. On programs that have an analog feed I don’t have this problem. Is this problem normal with DVD Recorders or could there be a problem with my recorder?

Thanks for any advice,