lfq521914
Newbie level 2
hello,
I am confused about the defination of the transfer funtion for a loop filter in PLL.
In the book "PLL Performance, Simulation, and Design" which was written by Dean,it is said that "the loop transfer function will be defined as the change in voltage at the tuning port of the VCO devided by the current at the charge pump.
In the cause of a second order loop filter,it is simply the impedance."But for a third order loop filter ,it is not the case according the defination mentioned above.
My question is ,how can I get the equation of the transfer function for a third order loop filter?Your help will be great appreciated.Thanks![/quote]
I am confused about the defination of the transfer funtion for a loop filter in PLL.
In the book "PLL Performance, Simulation, and Design" which was written by Dean,it is said that "the loop transfer function will be defined as the change in voltage at the tuning port of the VCO devided by the current at the charge pump.
In the cause of a second order loop filter,it is simply the impedance."But for a third order loop filter ,it is not the case according the defination mentioned above.
My question is ,how can I get the equation of the transfer function for a third order loop filter?Your help will be great appreciated.Thanks![/quote]