>From: Sean Murray[SMTP:SMURRAY@SLIP.NET]
>Sent: Tuesday, July 01, 1997 10:26 AM
>To: 'Signal Integrity'
>I'm a little confused on the subject of shielding (guard traces). I'm
>currently designing a board for a customer, in which the analog & digital
>traces are on seperate layers. Both layers are shielded by their respective
>planes (i.e. Digital by Dgnd; Analog by Agnd). My question is; do the
>analog traces still need to have guard traces to protect against any noise
>that might be coming from other analog traces on that layer? (and likewise
>for Digital). The customer has stated that he wants the traces shielded,
>but when asked why he could not give me a scientific answer. I was under
>the understanding that you only needed to shield the traces if they were
>very high speed and were not utilizing proper ground shielding (planes)
>M&M Specialties, Inc.