On Tue, Jun 3, 2014 at 4:12 AM, Tiankun Hu <tiankun...@foxmail.com> wrote:
> 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 > 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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