This document discusses modulation formats including minimum shift keying (MSK) and Gaussian MSK. It provides details on MSK such as it having a modulation index of 0.5, which makes the signals orthogonal and easier to separate at the receiver. MSK provides benefits like constant envelope, good spectral efficiency, and better bit error rate performance compared to frequency shift keying. The document also contains equations for MSK, diagrams of MSK transmission and reception, and information on the power spectral density of MSK and how it compares to Gaussian MSK.