Ripple Rejection Test
There are many ways to test the ripple rejection. This example is just one of them, but it does not require expensive test equipment for testing filters, regulators, etc. The setup is shown below.
The idea is simple. A dual-channel PSU is set to two different voltages, and a switchover device switches between them, creating a ripple at the output. It is easy to set up and modify the amplitude and offset of the ripple. The frequency and duty cycle depend on the control signal. And the PSUs and the DUT can be loaded properly.
The figure below shows a simplified switching circuit.
Despite its limitations, the circuit gives satisfactory solutions for many applications. One important thing is that V2 must be higher than V1 for the proper operation. The switching signal turns on and off the MOSFET connecting V2 according to the signal to the diode switching circuit, thus adding an AC component to the power at the output.