| 摘要 |
An Equalizer (11) with adaptiv viterbi analyser (VIT1) and channel estimation circuits (CEST1,...CEST16), connected to each a state (1,...16) of the viterbi analyser (VIT1). The equalizer (11) recieves 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 (C1(n),...C16(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 (ei,1...ep,16) of the transition error signals, old part impulse responses (Ci(n-1),...,Cp(n-1)) and transition vectors (Si1,...,Sp16). The estimation circuits (CEST1,...,CEST16) estimates the new part implulse responses (C1(n),...,C16(n)) for the new state (n) with the aid of the old part impulse responses (Ci(n-1),...Cp(n-1), the transition vectors (Si1,...,Sp16) and the transition error signals (ei1,...ep16). The part impulse responses (C1(n),...C16(n)) are utilized for estimation of symbols (S/< ANd >(n-L)). |
