Power Supply Ripple Simulation?

[ROBOT]

I need to do some testing at different frequencies with a waveform generator. Simulating various amounts of system noise.

I need a 5v signal with up to 1V pk sine wave at from 15KHz to 10MHz if possible. The device under test will be drawing no more than 100mA.

I have tried a few ways online on how to modulate noise onto a power supply using FETS and Opamps. However as soon as I increase the frequency beyond 5KHz the peak voltage drops and the amplitude maxs out at 10v while hardly in giving me a 100mV signal.

The circuit I tried was the first one on this link

http://www.electronicproducts.com/Test_and_Measurement/Benchtop_Rack_Mountable/Simulating_electrical_noise_from_power_supplies.aspx

I would appreciate the help. I can spend up to $400 making this work. I have power supplies and function generator Agilent 31220a.

[danadak]

The NE5534has a 13 V/uS slew rate, so this might be part of your
problem.

https://en.wikipedia.org/wiki/Slew_rate

One way of injecting noise would be switch a load using a MOSFET with
a random noise generator driving MOSFET. Very high speed can be achieved
if you meet the MOSFETs gate drive requirements. Or use a bipolar to switch
a load, base drive requirements might be easier for this application. Either case
switching to 10 Mhz quite doable.

Load switching works good in terms of evaluating regulator control loop performance.

Regards, Dana.

[vk6zgo]

If you are trying to superimpose ac on a dc supply,run the dc through one winding of a transformer,& feed your
AC signal into the other.

Back in the day,before we had purpose built "bump" generators,we used to test the clamping in Video Clamp Amplifiers by feeding the video through the secondary of a low voltage (3-5v) soldering iron transformer,with the primary Mains fed as normal.

The winding inductance messed with the video a bit,but it was an effective test of the Clamp Amps.
They all passed with flying colours,by the way!