Question in WBX daughterboard

Hello G.s
i need some help regarding WBX tuning frequency .
while checking C files in UHD , i’m still confused about the LO "local
oscillator " exists in C functions concerning the tuning frequency of
the WBX board
what’s exactly meant by the local oscillator frequency and what’s the
value of it in wbx db ? and in case of any frequency , how it’s divided
on both daughterboard and NCO in the FPGA ?
and what’s the IF frequency of WBX “or the range of IF frequencies if
it’s variable”
and in case of operating at GSM 1800 , it’s bandwidth is 75MHZ and the
dedicated filter for the WBX is only 25MHZ “knowing that i’m using a WBX
board for receiving and scanning GSM 1800 band” , so how to receive this
wide band although the available filter is only 25MHZ “while keeping the
data stream in on as i’m using FFT megacore to scan the whole band” ?

thanks in advance !