RE: [SI-LIST] : Conducted EMC Testing of PLL jitter

Farrokh Mottahedin (Farrokh.Mottahedin@quantum.com)
Wed, 9 Dec 1998 09:41:50 -0800

-Ray

> -----Original Message-----
> From: Farrokh Mottahedin
> Sent: Tuesday, September 29, 1998 1:33 PM
> To: 'Ray Anderson'; si-list@silab.Eng.Sun.COM
> Subject: RE: [SI-LIST] : Conducted EMC Testing of PLL jitter
>
> Ray,
>
> I don't consider myself an expert on this subject but would like to
> bring to your attention a piece of equipment available from HP which can
> be used for this application without direct or transformer coupling. The
> equipment I have in mind is called the 11945A Close-field Probe Set that
> can supply 0.5 watts of power over 9KHz to 1 GHz.
>
> Regards,
>
> Farrokh Mottahedin
> Quantum Corporation
> (408) 324-7934
> farrokh.mottahedin@quantum.com
>
>
> -----Original Message-----
> From: Ray Anderson [SMTP:raymonda@radium.Eng.Sun.COM]
> Sent: Tuesday, September 29, 1998 9:51 AM
> To: si-list@silab.Eng.Sun.COM
> Subject: [SI-LIST] : Conducted EMC Testing of PLL jitter
>
>
> Perhaps some of the EMI/EMC savvy people on the list have
> some comments and/or opinions on how best to couple an interfering
> RF signal into the power planes of a digital board to accomplish
> some EMC testing.
>
>
> Basically I have a system (CPU's, memory, PLL's etc.) that
> runs at a clock rate of several hundred MHz. I need to do
> some tests to evaluate what effect noise on the power planes
> over the range of ~DC to 1GHz has on the PLL jitter.
>
>
> I would like to inject a signal (in the range of ~DC to 1
> GHz)
> into the power planes (up to maybe 200 mv p-p amplitude) to
> see how the PLL handles the noise on it's power feed.
>
>
> I have a broadband (10KHz to 1GHz) amplifier that can
> provide
> an excitation level of up to 20 watts into 50 ohms.
>
>
> We believe the system power distribution system (planes,
> bypass
> caps etc.) looks like a broadband 50 milliohm (or less)
> impedance.
>
>
> The question is: would impedance matching the 50 ohm
> amplifier
> impedance to the sub-ohm plane impedance by means of a
> broadband
> ferrite transmission line transformer be a prudent thing to
> do,
> or is there another accepted way of doing this?
>
>
> Any comments or suggestions on alternate ways of evaluating
> the
> jitter performance of a system PLL in response to power
> supply
> noise over a wide bandwidth would be of interest.
>
> Ray Anderson
>
> Sun Microsystems Inc.
> raymonda@radium.eng.sun.com
>
>
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