Pujun

I need to compress a music file (wav format or mp3 format) to FM radio standard. I've tried the "Auto Grain Control". Although it does compress a sound file, the result is not exactly as what I heard on FM radio. The sound is not smooth at all. I do feel that the sound volume jump up and down frequently. How can I compress a sound file smoothly just like what most FM radio stations do? Thank you for help!