Pulse generator and source supply connection
If your glitch generator doesn't have to be ground referenced then it can be added in series with the output of a power supply. However, the glitch generator needs to have an internal circuit path to allow the power supply dc current unimpeded. If it does need to be ground referenced then the Power supply might be designed so that it doesn't need to be ground referenced i.e. an isolating DC-DC convertor would do this.