| Modulation Type | Description | Comments |
| FSK (Incoherent) | Carrier frequency is toggled between 2 values | Heritage modulation, simple, Doppler insensitive, Modulation Index is 0.3 |
| FSK (coherent) | Carrier frequency is changed with continuous phase shift | Requires less S/N for the same BER |
| GMSK (Gaussian Minimum Shift Keying) | Binary data is first Gaussian rounded before Applying to FSK | Similar to FSK except the Spectrum is more contained |
| PSK (Phase Shift Keying) | Carrier phase is changed ±90˚ | Improved BER performance |
| BPSK (Bi-Phase Shift Keying) | Carrier is modulated by a signal that is +1 or −1 | Efficient but Doppler sensitive |
| QPSK (Quadrature Phase Shift Keying) | Carrier phase is changed to one of four phases | Improved spectral efficiency. Two bits per step. Phase changes occur for every two bits of information |
| O-QPSK (Offset QPSK) | One of the two phase changes are delayed by one bit | Improved spectral efficiency. Phase changes occur every bit |