Rohde & Schwarz SML-B3

This Modulator option provides a high quality Pulse Modulation, featuring an on/off ratio better than 80dB and a rise/fall time shorter than 20ns.

The pulse modulator option allows pulsed signals to be produced independent of an external source, because an internal pulse generator is included.

But surely also external generated pulses can be used for the pulse modulator.

The Rohde & Schwarz, Inc. SMLB3 signal generator is an electronic instrument that generates repeating electronic signals.

It contains an electronic oscillator, a circuit that is capable of creating a repetitive waveform.