Dear all: Based on the talk about how to couple noise to the PDN of oscillator. I have gotten several solutions: 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 2. By means of 1:N transformer to lessen the dis-match. 3. By means of other IC, creat a noise source with low impedance. 4. By means of opamp, which is of low impedance. 5. Because the low impedance of oscillator PDN is capacitive, there would be a parallel resonance with a inductor(serial with a resistor). Hope this would be helpful. Original question: 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. Best Regards Zhangkun 2008.5.16 ------------------------------------------------------------------ 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