Abstract: Estimation of symbols related to each other by a parity relationship previously created by an encoder, is effected by a function having several components effecting a calculation of probabilities corresponding to a state of the encoder. The probabilities are of a first type, resulting from the observation of the effects of the previous states of the encoder on the current state, of a second type, resulting from the observation of the effects of the subsequent states of the encoder on the current state, and of a third type, representing the belonging of a symbol to a predetermined part of an encoding alphabet. A specific multiplexer is controlled by a state machine and cooperates with a calculator so that not only the probabilities of the first and second types but also the probabilities of the third type are obtained by one and the same circuit.

Abstract: According to one aspect of the invention, estimation of symbols related to each other by a parity relationship previously created by an encoder, is effected by a function having several components effecting a calculation of probabilities corresponding to a state of the encoder. The probabilities are of a first type, resulting from the observation of the effects of the previous states of the encoder on the current state, of a second type, resulting from the observation of the effects of the subsequent states of the encoder on the current state, and of a third type, representing the belonging of a symbol to a predetermined part of an encoding alphabet. A specific multiplexer is controlled by a state machine and cooperates with a calculator so that not only the probabilities of the first and second types but also the probabilities of the third type are obtained by one and the same circuit.