the Bandwidth of a costas PLL using in BPSK demodulation?

[machael]

costas pll

Hi guys!

I'm doing a project: using a DSP to demodulate a digital packet which is modulated by BPSK. Because the phase noise is a little big, so I decide to use coherent demodulation by a digital Costas PLL.

I've found a pretty good tutorial about costas pll named<Carrier Recovery Using a Second Order Costas Loop> by google. And this article provide the method to decide the two parameters in the loop filter of a costas pll.

\[\alpha=2\zeta(\frac{2B_lT_s}{\zeta+\frac{1}{4\zeta}})\]

\[\beta=2(\frac{2B_lT_s}{\zeta+\frac{1}{4\zeta}})^2\]

in which, \[\zeta=0.707\]

However, How to decide the \[B_l\], the bandwidth of the loop filter? is it should be correlated to the bandwidth of the BPSK signal?

Thanks a lot!

 

[scott.zhang]

bpsk demodulation

the Bl is equivalent bandwidth for PLL,equivalent ,choosing Bl<= 0.1Rb,where Rb is data rate.