[SI-LIST] Re: transient and non-transient signals in Jitter analysis

  • From: "Jeon, Tae-Kwang" <Tae-Kwang.Jeon@xxxxxxx>
  • To: "Saoer Sinaga" <saoer.sinaga@xxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
  • Date: Tue, 27 May 2008 19:24:22 -0600

Saoer,

For jitter analysis, I guess you don't have to deal with non-transition
signal for a given waveform unless there is amplitude-to-phase
modulation. If you are able to dump your waveform from your tools, you
might want to try this pseudo code in order to extract the transition
part of your data.

(If you are familiar with Python, it should be easier for you to go
though the code)

=3D=3D=3D=3D
cross_zero(data, threshold):
    ### returns an array of crossing times.
    ### data is assumed to include [time, voltage] pairs in array
    ### threshold represents the crossing threshold

    crosses =3D []        # empty array
    t1,v1 =3D data[0]     # the first entry of the data array
    v1 =3D v1-threshold
    for t2,v2 in data[1:]:  # get the [time, voltage] pair out of
                            # the array starting from the second entry
        v2 =3D v2- threshold;
        # We have found a falling edge=20
        if (v1 > 0 and v2 <=3D0):
            ## collect interpolation data
            ## interpolation is done for time based on v1 and v2
            crosses.append((t2*v1-t1*v2)/(v1-v2))
        # We have found a rising edge=20
        if (v1 < 0 and v2>=3D0):
            crosses.append((t2*v1-t1*v2)/(v1-v2))
        t1 =3D t2; v1 =3D v2;
    return crosses
=3D=3D=3D=3D

Hope this helps,
TK

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On Behalf Of Saoer Sinaga
Sent: Wednesday, May 21, 2008 4:42 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] transient and non-transient signals in Jitter
analysis

Dear all,
In Jitter analysis, you need to separate transient signals and
non-transient
signals from serial signals.
What do transient and non-transient signals actually mean here?
Does the transient signal mean the signal that always changes
(1010101....)
? and what about the non-transient signal ?

How can I separate those two types of signals in simulation tools e.g.
Cadence?

thanks,
Saoer


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