Pulse and Spectrum Manipulation in the Minimum (Frequency) Shift Keying (MSK) Format

The minimum (frequency) shift keying (MSK) format is generalized to enable further improvements in the spectrum while retaining the well-known constant envelope property and the excellent communications efficiency of MSK. A specific alternative to MSK is presented, and the spectrum is compared with that of MSK. The theoretical limitations on possible further spectrum improvements are discussed.