how to simulate the PSRR in transition simulation ?

[twonsr]

hi :

I have a trouble to simulate the PSRR about my voltage regulator.
I want to know my circuit's stability with vdd fluctuation , so I let my vdd to be a sin wave as sin( 10 15m 10k 0 0 0 )
10 is the vdd , 15m is the amlitude and 10k is the frequency.
And then I give a ".TRAN" instruction to get the output's fluctuation.

But I find if I add accurate=1 in options , the result will change very much.
Why ?

If my simuation method is wrong , please help me and give me some suggestion.
Thank you very much.

 

[rambus_ddr]

I use a AC source in power supply and see the output ac magnitude.

 

[twonsr]

I knew that AC simulation.

But if the vdd includes some sin wave , we will see it is decayed in our output.That is why we need a higher psrr to get a stable output, right ?

 

[layes2]

add a ac signal 1V at the power and measure the output use .ac
you can get PSRR from it