Natural Log
A logarithmic response: y changes by the same amount each time x is multiplied by the same factor. Use it for sound levels in decibels and other responses proportional to the logarithm of a stimulus.
Parameters
- Change in y when x increases by a factor of e (about 2.718). The change for each doubling of x is A ln 2.
- The x at which y = 0, in the units of x.
Tips
- x/B must be positive: x and B have the same sign, and x cannot be 0.
- Automatic starting values come from a straight line fitted to y against ln x, so they need positive x.
- For a sound intensity level in decibels, A = 10/ln 10 ≈ 4.343 and B is the reference intensity.