i am trying to design a decimator for sigma delta converter . my decimation factor is 48. from material i found i decided on a CIC filter for first stage (decimation of 24) and a CIC filter as second(decimation of 2).

sampling freq =3840 KHZ
Fin = fin = 0-80khz
stop band attenuation = 100 dB

About the SINK filter according to Hogenauer's paper wordlength is:
N*log(R*M)+Bin -1=3*ln(24)+2-1=10 bits
N(number of section)=3;R(decimation factor)=12;M(differentiel delay)=1;Bin(Binary input 0 or 1)=2
after simulation i obtain this:

What can i do ?

Thanks for help