The invention relates to a turbo decoder which is provided for decoding a data signal (D) transmitted over a disturbed channel and which comprises a symbol estimator (MAP_DEC). Said estimator comprises a computing means which, by using the knowledge of the fault protection code used on the side of the transmitter, calculates transition metric values, forward and reverse recurrence metric values, and which calculates the output values (LLR) therefrom. The computing means comprise at least one hardware calculating module (RB1/2/3), which is constituted of at least one combinatory logic, for generating at least one type of said values. |