| 摘要 |
An equalizer (11) with adaptive viterbi analyser (VIT1) and channel estimation circuits (CEST1,...CEST16), connected to each a state (1,...16) of the viterbi analyser (VIT1). The equalizer (11) receives a signal (y(n)), which has been filtered and sampled at decided timepoints (n) and which during its transmission has been subjected to time dispersion. For each state (1-16) the estimation circuits (CEST1,...,CEST16) estimates each a part impulse response (C (n),...C (n)) for the channel. The estimation is iterative and comprises the steps: the viterbi analyser calculates transition error signals between an old and a new state with the aid of a preceding part impulse response. The viterbi analyser (VIT1) selects the best ones (e i,1...ep, 16) of the transition error signals, old part impulse resposes (C i(N-1),...,C p(n-1)) and transition vectors (S i1,...,S p16 ). The estimation circuits (CEST1,...,CEST16) estimates the new part impulse responses (C1(n),...,C16(n)) for the new state (n) with the aid of the old part impulse responses (C i(n-1),...C p (n-1)), the transition vectors (S i1,...,S p16) and the transition error signals (e i1,...e p16). The part impulse responses (C1(n).,,,C16(n)) are utilized for estimation of symbols ((n-L)).
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