Gardner timing sync loop quetion

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

On Tue, Jun 3, 2014 at 4:12 AM, Tiankun Hu [email protected]
wrote:

My quetion is how to define BL, anyone can tell me how to calculate it
from PPM(ADC’s freq offset)?

Thanks
Tiankun

Take a look at this:

http://www.trondeau.com/blog/2011/8/13/control-loop-gain-values.html

I don’t think it exactly answers your question, but might be helpful.
Also,
we have the gr::blocks::control_loop class that you can inherit from to
make this easier for you to use. See the costas_loop_cc block for an
example of how.

Tom

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