Someone sent me the image below, and I think I'm confused as well.
Is the second formula (modulation) correct? What does it mean? From the symbol, I think it represents capacity, but it doesn't make much sense to me.
1. Shannon capacity: $ C = B \log_{2}(1+\text{SNR}) \text{ bps} $
2. Modulation: $ C = B \log_{2}(M) \log_{2}(1+\text{SNR}) $