Defines mobile radio receivers having audio-frequency bandwidths (the receiver does not necessarily have an audio output) generally not exceeding 10 KHz for the reception of voice and other types of signals, using: a) angle (Type G or F; phase of frequency) modulation, or b) double-sideband amplitude (Type A) modulation with full carrier, or c) single-sideband amplitude (Type H, J or R) modulation with full, reduced or suppressed carrier.