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https://designers-guide.org/forum/YaBB.pl Measurements >> Phase Noise and Jitter Measurements >> Reference effect on PLL PN https://designers-guide.org/forum/YaBB.pl?num=1541170315 Message started by Farzaneh on Nov 2nd, 2018, 7:51am |
Title: Reference effect on PLL PN Post by Farzaneh on Nov 2nd, 2018, 7:51am Hi, I followed Ken's paper "Predicting the Phase Noise and Jitter of PLL-Based Frequency Synthesizer" to simulate the PN of PLL. I also imported my data to Matlab. The problem is that the PN that I got from Matlab is like my open loop VCO and when I remove or add reference jitter the PN is same. I also tried it for the example at the end of paper, in this case the PN is like PLL PN but when I remove reference jitter, again there is no difference. what the problem is? Farzaneh |
Title: Re: Reference effect on PLL PN Post by Ken Kundert on Nov 2nd, 2018, 9:57pm Is it possible that the other sources of noise are dominating over the noise from the reference. -Ken |
Title: Re: Reference effect on PLL PN Post by Farzaneh on Nov 2nd, 2018, 10:05pm No, because only VCO and reference have noise and my PFD/CP isn't noisy. My blocks are exactly same as example at the end of paper and I only change the values with my values. Farzaneh |
Title: Re: Reference effect on PLL PN Post by Ken Kundert on Nov 3rd, 2018, 11:38pm Why didn't you also turn off the noise in the VCO as well? -Ken |
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