[Discuss-gnuradio] Gardner timing sync loop quetion

[Tiankun Hu]

Hi all,
I am designing a 2 order Gardner timing sync loop(with 1 order PI loop filter) for QAM64.
As Best's PLL book metioned, timing sync loop's parameter can be calculated by using PLL theory.
Now I need calculate the PI loop filter's factor K1(P gain) and K2(I gain). According PLL theory, we can get them from Wn(nature freq) Kd(phase detector gain) Ko(NCO gain).
I can get Kd from open loop simulate, and Ko equals to 1
Wn can get from BL(noise bandwidth).
My quetion is how to define BL, anyone can tell me how to calculate it from PPM(ADC's freq offset)?


Thanks
Tiankun