Creating DC Noise - On Pourpose

[iceblu3710]

Sounds strange I know but all of my DC supplies on my bench output a beautifully clean voltage, less than 0.5V regulation across its entire load range.

I am building and understanding PSU filters but in order to test them I need a way of creating common types of noise such as spikes, dips, random noise, HF noise. I tried plugging in a vaccume to the same circuit as my DC supplies but them clean the noise right up so I want to make my own noise generator.

Anybody done anything like this before? The only idea I could come up with was a uC running a power mosfet to a heavy inductive load and choosing if I want random output or a specific PWM to the motor to introduce some switching noise.

Any Ideas welcome! Thanks!

 

[enjunear]

Since you want to induce time-varying signals onto a DC line, you could run the power supply output through one winding of a small transformer. The other side of the transformer would be used to inject your signals (DC isolated, so you could put any circuit you can dream up on the "injection" side of the xfmr).