47 CFR 95.371: Emission types.

In general, Personal Radio Services stations may transmit any emission type that is appropriate for the permissible uses of the specific service, provided that it does not exceed the authorized bandwidth for that service and is in full compliance with the modulation limits (if any) and unwanted emission limits for the specific service.

(a) Exceptions. In some of the Personal Radio Services, stations may transmit only certain specific emission types. Any such limits are set forth in the emission types rule in the subpart governing that service. See e.g., §§ 95.971 and 95.2971.

(b) Emission type designators. Emission type designators are defined in § 2.201 of this chapter. Designators for emissions commonly used in the Personal Radio Services are as follows:

Description Designator

Voice, AM A3E

Voice, SSB J3E

Voice, FM F3E

Voice, PM G3E

Data, FSK F1D

Data, AFSK F2D

Data, PSK G1D

Test, no modulation N0N