set baseband filter bandwidth

Hello, I use your library and all work perfect, but I don't understand how to change baseband filter bandwidth?
For example, in hackrf_transfer I can change baseband with option -b and choose one of the next values 1.75/2.5/3.5/5/5.5/6/7/8/9/10/12/14/15/20/24/28MH 
http://manpages.ubuntu.com/manpages/xenial/man1/hackrf_transfer.1.html