# Define the positive and negative of PSRR [closed]

How to define the positive and negative value of PSRR? How to differentiate them ? How does it change with frequency ? What is the advantages of high or low value of PSRR ? How does it affect the output signal i op-amp?

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 "the positive and negative value of PSRR" Huh? This question makes little sense and needs to be closed. – Olin Lathrop Oct 11 '12 at 13:07 Answer: PSRR = 20 log10 ( power supply variation / output ripple variation ) => positive dB PSRR = 20 log10 ( output ripple variation / power supply variation ) => negative dB – nee Oct 12 '12 at 7:13 @nee - it doesn't make much sense to calculate two separate positive/and negative values for CMRR, you only need one or the other as they both express the same ratio. All swapping the division round does is make the dB the same value but negative. For example 20 * log10(10/1) = 20dB and 20 * log10(1/10) = -20dB – Oli Glaser Oct 12 '12 at 9:54

## closed as not a real question by Olin Lathrop, Brian Carlton, Dave Tweed, stevenvh, Oli GlaserOct 12 '12 at 5:49

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, see the FAQ.