[SI-LIST] Another answer for how to couple noise to the PDN of oscillator
- From: "Buchs, Kevin" <buchs.kevin@xxxxxxxx>
- To: "Zhangkun" <zhang_kun@xxxxxxxxxx>
- Date: Tue, 20 May 2008 15:16:03 -0500
Zhangkun,
One more idea I might add is one we have used to build a sort of balun
impedance transformer from a pair of coax cross-wired. Getting some 25
ohm coax is the part that costs a bit, but otherwise it is a cheap,
reusable approach. This idea originated with Jonathan Fasig in our
group and we have successfully employed it to inject noise into a
low-impedance PDN from 50 ohm sine sources and pass-through noise
generators operating in the 200-400 MHz range. We were able to test for
PLL sensitivities to PDN noise. =20
A reference to check is Transmission Line Transformers by Jerry Sevick,
SciTech Publishing, 2001. =20
Kevin Buchs Mayo Clinic 200 1st St. SW Rochester, MN 55901
buchs.kevin@xxxxxxxx 507-538-5459 http://www.mayo.edu/sppdg
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On Behalf Of Zhangkun
Sent: Friday, May 16, 2008 3:15 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Answer for how to couple noise to the PDN of
oscillator----Thank you all for the help and the discussion
Dear all:
=20
Based on the talk about how to couple noise to the PDN of oscillator. I
have gotten several solutions:
=20
1. Do not consider the dis-match
1) Connect the signal to the PDN directly
2) Measure the coupled noise on the PDN
3) Calculate the ratio between the noise and the jitter
=20
2. By means of 1:N transformer to lessen the dis-match.
=20
3. By means of other IC, creat a noise source with low impedance.
=20
4. By means of opamp, which is of low impedance.
=20
5. Because the low impedance of oscillator PDN is capacitive, there
would be a parallel resonance with a inductor(serial with a resistor).
=20
Hope this would be helpful. Thank you for the discussion.
=20
=20
Original question:
=20
Now we are studying the effect of power noise on jitter. We meet a
problem, how to couple noise to the PDN. For example, we want to couple
noise of 25MHz into the PDN of oscillator. However there is impedance
dismatch. The impedance of signal source is about 50ohm and that of PDN
is about 0.1ohm.
The energy would be reflected.
=20
Best Regards
=20
Zhangkun
2008.5.16
=20
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at: =20
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
=20
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
- » [SI-LIST] Another answer for how to couple noise to the PDN of oscillator
