Hi, ferrite bead for low frequency application (below 20MHz) available on the market, do not have high impedance (few tens of Ohm) and therefore do not have advantages over other components normally used as filters (R-L-C).
hi,
you can just use a R-C filter,better work than ferrite. With the formula f=1/(2*3.14*R*C). one high pass & one low pass R-C circuit will help you to get your range of 1-20Mhz
the deign is there in the attachment
Also, realize that they will not reject RF as well or steeply as an actual lowpass filter. It does have the advantage that it will do so in a lossy way, without reflecting the energy.