AM means Amplitude modulation, FM means Frequency modulation. Lets see some of the main similarities between AM and FM Modulation here on this page.
Similarities between AM and FM Modulation
1. Both are the ways for broadcasting radio signals.
2. You could select what carrier or channel you would like on AM and FM.
3. Both have their own carrier and wave frequency.
Similarity between AM and FM Modulation
Similarities between FM Modulation and AM