Conversion formula for converting amplitude ratio $($AR$)$ into decibels is

Decibel $=20$ log$10($AR$)$

Decibel $=20$ loge $($AR$)$

Decibel $=20$ log$10($AR$)0\mathrm{.}5$

Decibel $=20$ loge $($AR$)0\mathrm{.}5$