# RMS and PP noise in LTSpice noise analysis.

#### Yesman0019

##### New Member
I'd like to know the definition equations of RMS and PP noise in LTSpice noise analysis.
I asked this question to LTSpice User Group, but they told that they could not explain.
I think RMS is something like standard deviation of noise in frequency domain and PP is 99%-sigma.
But, what I found by a simulation, PP was much lager than 99%-sigma of RMS noise by LTSpice.
I attached a part of my measurement in LTSpice noise analysis.
And the definition of RMS I saw on the net.

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