Don't worry about the way I measure the spikes.  I do use J-Fet buffered 1.5GHz probes 
with the miniature GND spike pin which is
right next to the probe signal pin.  On my PCB, I placed GND & supply test points 
around the PLD just for such an emergency.

I do know that when measuring any signals here, even stuff in the 10 MHz range, the 
conventional 10x probes suck royally.

Scope snapshot coming in 2 hours...

____________
Brian Guralnick
[EMAIL PROTECTED]
Voice (514) 624-4003
Fax (514) 624-3631


----- Original Message -----
From: "Richard Sumner" <[EMAIL PROTECTED]>
To: "'Protel EDA Forum'" <[EMAIL PROTECTED]>
Sent: Monday, September 09, 2002 2:24 PM
Subject: Re: [PEDA] off topic supply SOS


> Brian,
>
> Measuring spikes on the supply lines is not trivial. Where you put the
> scope probe ground is everything. The best way to measure is with a
> differential probe, placed across the power pins of the chip in question.
> Anything less may not give you the true picture.
>
> Don't misunderstand, this is not a criticism, but a heads up. Be alert when
> making this kind of measurement.
>
> Richard
>
>
>
> Cheesecote Mountain CAMAC,  24 Halley Drive; Pomona, NY 10970
> voice: 845 364 0211, fax: 845 362 6947,  www.cmcamac.com
>
>
> ************************************************************************
> * Tracking #: FD6D883A80FDAD4CBE28A8F34C309861BFE3E3E7
> *
> ************************************************************************

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