Medium-to-long explanation follows this executive summary:

Has anyone noticed any noise issues related to Dell laptop
power supplies?

Full story:

I'm working with meidum precision analog signals-
16 bit (hopefully).  We were noticing intermittent noise in
the output, which was usually present.  The acquistion
system is connected to the computer via vanilla serial
(no USB adapter, just a port on the laptop).  Finally, the
noise can be eliminated by unplugging the supply from
the laptop.  Unplugging the supply from the wall doesn't
help, only unplugging the supply from the laptop.

The long-term solution is optical isolation, but I'm curious
as to whether this is something others have encountered.

We haven't tried connecting it to other PCs yet, as we
don't have any on hand for testing.  I did notice a similar
problem with my newer model Inspiron- terrible noise
when I connect to my stereo for listening to music.

Mike H.

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist