The replies to this comment are missing your point. It's not just the power of the FM signal, it's the amount of extraneous junk outside the FM band that will be a problem. This is a very dirty signal generator.
Band-pass filter: select only a desired band of frequencies
Band-stop filter: eliminate an undesired band of frequencies
Low-pass filter: allow only frequencies below a cutoff frequency to pass
High-pass filter: allow only frequencies above a cutoff frequency to pass
