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 e2 (I am not making this up!) or about 7.4 and corresponds to approximately 8.7dB. -1 Np is about 0.135 (1/e2). A decibel is 10 log(a/b)