I know what's the noise - that is output ripples's ripple - on the peak-peak points.
But What should I do when I measure this?

I thought using the PSRR measurement circuit,
connecting OSC parallel.
But, the PSRR would be measured too.

What is the better circuit for this?

 

hi,
Use an oscilloscope probe, with the scope Y amp channel set for AC input, say 10mV or 50mV.
E