Precoding for a non-linear codec

[Subject] The prior coding for attaining a rate higher than 33.6k bps in the direction of a digital modem from an analog modem and a decoding system are submitted. [Solution means] プリコーダ 10 also contains the feedback filter 12. The feedback filter 12 generates the feedback signal 16 as a function of the mapping Constellation signal 18, and the discrete modulo adding machine 14, The mapping Constellation signal 18 is generated as a function of the input signal 20 to プリコーダ 10 as a function of the feedback signal 16. A discrete modulo adding machine is the [selection figure] figure 1 using the index to the Constellation level chosen about プリコーダ 10 so that the amplitude of the mapping Constellation signal 18 may be restricted.