< standard > The ITU-T standard for nonuniform quantising logarithmic compression .
The equation for A-law is
| A | ------- (m/mp) |m/mp| = Values of u=100 and 255, A=87.6, mp is the Peak message value, m is the current quantised message value. (The formulae get simpler if you substitute x for m/mp and sgn(x) for sgn(m); then -1 Converting from u-LAW to A-LAW introduces quantising errors . u-law is used in North America and Japan, and A-law is used in Europe and the rest of the world and international routes.
[The Audio File Formats FAQ]
(1995-02-21)