Hao, Your reply did not answer my questions. This does not resolve my issue. Perhaps I should have said that NO current answer in this forum meet my needs. I KNOW how to do the calculations, I NEED an explanation of the parameters P Q R and "N"…
John,
With a phase detector frequency of 200 MHz and a fractional denominator of 20 you can get spurs at 200MHz/20 = 10 MHz and also sub-fractional spurs at 200 MHz/20/2 = 5 MHz. You will find that if you switch to the first order modulator, the spurs…
Eric,
I have no closed form solution for the seed calculation, but PLLatinum sim does it by calculating the spurs based on the seed and picking the best one.
A worked example using seed impact on fractional spurs is in my online manual at ti.com/tool…
Hi Yusuke,
Please refer to chapter 16 of Dean's PLL book: http://www.ti.com/tool/PLL_BOOK
To start with, you need to check if the spur is inside or outside of the loop. To do so, reduce the loop bandwidth by reducing the charge pump gain. Observe if…
Hello Satoshi-san,
Please refer to chapter 46 of www.ti.com/.../PLL_BOOK
Specifically page 442 (448 by PDF) shows the circuit.
Section 6.11 on Page 18 of the LMK03001 datasheet describes the digital lock detect.
I recommend using the digital lock detect…
Toshihiro-san,
This sounds like the integer boundary spur. It is modeled by the PLLatinum Sim tool and this tool can give insights into spurs. It is not a simple topic, but spurs are discussed in my PLL book at ti.com/tool/pll_book.
A few things I…
Kawai,
The gamma optimization parameter is discussed in great depth in my online PLL book "PLL Performance, SImulation, and Design" at ti.com\tool\pll_book.
The clock architect is good for part selection and frequency planning, but the…
Hello Satoshi-san,
#1) I've seen noise/vibration from fans cause spurs in the 10 Hz to 200 Hz range. I never did confirm if it was the loop filter capacitors or some other mechanism, but this is an example of where mechanical noise could impact your…
Ilya,
1) Attached is a plot from which the jitter was derived. To calcul;ate jitter, integrate the area and call this A. Don't forget to multiply by 2 for both sides. Then the jitter is sqrt(A)/(2*pi*f), where f is the frequency. This is also discussed…