External FM can be applied by connecting an AF source to the rear panel modulation input. With the internal modulation generator option, a modulation generator provides frequency modulation of the source or generates pulse trains that can be applied to a pulse modulator to pulse modulate the source. Pulse trains can be generated as repeating single pulses or as complex multi-pulse patterns. An option for an internal pulse modulator is available, the pulse modulator can be driven with either the optional internal generator or from an external pulse generator
connected to the rear panel input connector.
