Generate runt pulse.

[perfect_disturbance]

I was reading the users guide for  the Rigol DG 4000 series function generators and trying to figure out how Dave generates the periodic runt pluses he uses to test refresh rate in some of his oscilloscope review videos.  Does anyone here know how to do that?

[AndyC_772]

Generate two streams of pulses with a microcontroller or CPLD, which are usually the same but occasionally differ. Join the two outputs together with a pair of resistors, and probe the point where they join.

[jpb]

There are various scope testing boards that will do this - e.g. Rigols DS6000:

http://www.batronix.com/pdf/Rigol/UserGuide/DS6000DemoBoard_UserGuide_EN.pdf

otherwise arbs with a sequencing capability can do this easily (e.g. Agilent 33500 series or ones with a variable clock such as the Tabor WW5061).

[perfect_disturbance]

I thought he was doing this with a Rigol DG4000 series but apparently that's not the case.  I guess I'll have to build my own .