Query in AD9371 Evaluation Board  VCXO selection doc

With reference to https://ez.analog.com/docs/DOC-16454


From the AD9528 data sheet: 

M1 = 3,4,5

Also it appears from the diagrams Figs 27 & 30 that the x 2 multiplier is in series with the 5 bit divider. it appears (Table 50) that this can be enabled with any value of R1 divider, If this is true then additional dividers possible are:

0.5, 1.5, ... 15.5 

Finally, regarding the requirement 

Maximum frequency after the RF VCO divider (M1) is limited to 1000MHz

I don't find any such limitation in the data sheet. I do see (Table 8)

Output Frequency 1000MHz or 1250MHz otuputs 1 and 2 only

However output is after channel divider. is it possible that the channel divider will work with input < 1250MHz 


Please verify