about FSK data question....

super

Dear all :
. J! _. O- H( S$ I( k9 n              In fsk close loop direct Frequency modulation ,
          1.  data rate is higher than loop BW  or lower than loop BW ?
          2.  And what's the relation between data rate and Loop BW ?
% I) W$ c/ V% q$ J7 z
           Because modulation from VCO , it's a high pass function for VCO vs PLL.
           If modulation frequency > BW , it will be supress by VCO vs PLL transfer function.
           It will be trace and fix it.  So modulation function is fail.
             Is this concept is right ?
                  
2 e$ T( b) g4 h5 E% o                    Thanks .

simenkid

1.data rate可以高於loop bandwidth, 也不可以.端看用什麼architecture
, a7 I- h; M+ b& z1 [2.假使單純在multi-modulus或是由reference端做調制, data-rate高於loop bandwidth則勢必產生失真

0 {2 H5 K1 O! M" \- Z7 w直接由PLL Synthesizer調制提升FSK, FM, GMSK等固定波包調制之data rate
可選擇如pre-emphasis或two-point modulation(同時兼顧inband與outband,理論上無頻寬限制)的方式