liletian wrote on May 9th, 2009, 7:12pm: when I mentioned it, it means the RC filter's pole location. 1/(1+w/w0).
First question, you are really using a RC filter (one R and one C)? If that is true, what kind of phase comparison circuit are you using?
liletian wrote on May 9th, 2009, 7:12pm:I guess you guys definition is "The loop bandwidth is defined as the
integrated magnitude of the PLL frequency transfer function over
the entire frequency spectrum." please let me know.
Yes, I think we are all talking about pll bandwidth, not the loop filter bandwidth.
liletian wrote on May 9th, 2009, 7:12pm:Also, how can you see my PLL's loop bandwidth is less than 500MHz.
I did not check you spectrum, but first of all, if you vco is free running, no information can be seen from your meansurment. And loop bandwidth of 500MHz is very big, and if that is true, what is your comparison frequency? If you can tell your loop filter R and C values, PFD/PD structure, kvco, maybe I can help you to figure out what might be wrong.
cheers
rfmems