Theef="module.php?name=Lexikon&file=search&eid=1&query=ITU-T">ITU-Tef="module.php?name=Lexikon&file=search&eid=1&query=standard">standard for {nonuniform quantising logarithmic compression}. Theequation for A-law is | A | ------- (m/mp) |m/mp| =< 1/A | 1+ln A y = | | sgn(m) | ------ (1 + ln A|m/mp|) 1/A =< |m/mp| =< 1 | 1+ln A 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 <= x <= 1.) Converting from ef="module.php?name=Lexikon&file=search&eid=1&query=u-LAW">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)
