I saw sb. use eqution to calculate Delta fvco=200K*(M*K/(M-K)), 200k is the channel spacing for GSM, what is M, K? how to choose the M,Kvalue? where I can find the detail explaination for this equtuion? then how to choose R conter value? if the cystal freq. is 19.2MHz, then R=19.2/deltafvco, right?