[SI-LIST] Re: Accounting random jitter

  • From: "Pratt, Gary" <gary_pratt@xxxxxxxxxx>
  • To: <ray.anderson@xxxxxxxxxx>, <james.plesa@xxxxxxx>, <scott@xxxxxxxxxxxxx>, <edpc108@xxxxxxxxx>
  • Date: Tue, 23 Aug 2005 15:32:29 -0400

Mentor's Eldo can use all the normal linear noise analysis device
specifications (flicker, thermal, junction, etc) in a transient analysis
as described by this excerpt from the Eldo manual:

Transient noise simulation can be applied to all types of circuit
without restriction. To perform
transient noise analysis, physical noise of electrical devices is
emulated by time dependent
current sources. The frequency characteristics of these sources are
referred to the noise models
of the noisy components. The method used is simple, fast and does not
disturb the simulated
behavior of the circuit because the noise signals introduced are
continuous and fully
deterministic.

However last I'd heard, this was unique to Eldo with the other SPICE
derivatives behaving as Ray described. =20

One could also incorporate any type of desired time-domain noise effect
in IBIS 4.1 AMS models. =20


Gary



-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On Behalf Of Ray Anderson
Sent: Tuesday, August 23, 2005 1:34 PM
To: james.plesa@xxxxxxx; scott@xxxxxxxxxxxxx; edpc108@xxxxxxxxx
Cc: si-list@xxxxxxxxxxxxx; Ray Anderson
Subject: [SI-LIST] Re: Accounting random jitter

I always thought the .noise function in spice merely determined the
total RMS noise contribution of the various circuit components
(resistive and active) whose noise performance could either be
calculated or was specified. It isn't obvious to me that this function
can be used to inject jitter into a time domain simulation.

Can spice's Monte Carlo statistical capabilities be applied to the zero
crossings of a voltage source? I've always thought that it could only
statistically vary component values.

On the other hand one could probably generate a random noise voltage and
sum it with a reference voltage in a comparator to cause random jitter
on the output of the comparator. Alternatively, the random noise source
could be used to modulate a behavioral VCO clock source. This basically
emulates some techniques that can be applied to physical test equipment
in the lab.


-Ray


-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On Behalf Of Plesa, James T.
Sent: Tuesday, August 23, 2005 11:00 AM
To: scott@xxxxxxxxxxxxx; edpc108@xxxxxxxxx
Cc: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: Accounting random jitter

Most or all SPICE simulators that I have used have included .NOISE
analysis and Monte-Carlo analysis, either of which would seem suited to
introducing eye-diagram jitter.=3D3D20

Jim Plesa
Northrop Grumman Corp.=3D3D20

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On Behalf Of Scott McMorrow
Sent: Tuesday, August 23, 2005 12:45 PM
To: edpc108@xxxxxxxxx
Cc: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: Accounting random jitter

Jayaprakash

Unfortunately, no.  SPICE is a deterministic simulator and does not
simulate stochasic (random) processes.  You will need something like
Agilent ADS, Ansoft Designer, StatEye, or roll-your-own Matlab code to
integrate random noise into your simulations.=3D3D20

regards,

Scott

Scott McMorrow
Teraspeed Consulting Group LLC
121 North River Drive
Narragansett, RI 02882
(401) 284-1827 Business
(401) 284-1840 Fax

http://www.teraspeed.com

Teraspeed(r) is the registered service mark of Teraspeed Consulting
Group LLC



Jayaprakash wrote:

>Hi,
>
>  Is there a std. way to include/account random jitter effects in =3D
a=3D3D20
>typical eye diagram simulation in SPICE?
>
>  Thanks and regards,
>     Jayaprakash.=3D3D20
>
>
>       =3D3D09

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