SI unit for the

ratio of two

numbers expressed using a

natural logarithm formula:

For two scalar values *a* and *b*, the value of Np is ln(^{a}/_{b})_{/2}

1 Np is equal to a ratio of e^{2} (I am not making this up!) or about 7.4 and corresponds to approximately 8.7dB. -1 Np is about 0.135 (1/_{e}2). A decibel is 10 log(^{a}/_{b})