Re: [SI-LIST] : Measuring Ground Noise

Dima Smolyansky ([email protected])
Tue, 23 Jun 1998 18:58:03 -0700

Agreed on all points. What follows, however, is that you can measure
localized noise on your ground plane - you just need to figure out what
your reference point will be.

Thanks,

-Dima Smolyansky

----------
> From: Larry Smith <[email protected]>
> To: [email protected]; [email protected]
> Subject: Re: [SI-LIST] : Measuring Ground Noise
> Date: Tuesday, June 23, 1998 8:14 AM
>
>
>
> > Can anybody suggest a good way of measuring Noise on GND around
> > devices?
> >
> > Thanks,
> > Mark Nass
>
> Measure Gnd noise with respect to Vdd... At signal integrity
> frequencies, there is no such thing as an ideal reference point. All
> signals and noises are differential (something with respect to
> something else). A high bandwidth single ended probe with short (1/4
> inch, if possible) leads for both Vdd and ground will work well. You
> can measure Vdd WRT Gnd as well as any signal WRT ground. This is
> excactly what a device located at that position will see and respond
> to.
>
> regards,
> Larry D Smith
> Sun Microsystems
>
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