Model 533X-11M, variable repetition rate impluse generator (VRRIG) is a calibrated broadband signal source primarily intended for use as a calibrator when performing subsitution type interference measurements. The 533X-11M pulse repetition rate is variable from 50 Hz 5 MHz or it may be triggered by the power line frequency, an external trigger source or manually. The availability of these various operating modes provides versatility not found in other impulse generators. The model 533X- 11M is completely solid state and applications for it include: calibrated broadband signal source; used as a calibrator for subsitition type broadband interface measurements; receiver bandwidth measurement and rapid gain checking of tuners.