| 摘要 |
In a signal processor for processing a multilevel signal, a partial response equalizer is provided having a first predetermined number of reference amplitudes. The equalizer receives the multilevel signal and detects a significant instant of amplitude transition of the multilevel signal with respect to the reference amplitudes and produces a signal representative of the amplitude at the detected significant instant. The amplitude representative signal assumes one of a second predetermined number of amplitudes including spontaneously generated amplitudes, the second predetermined number being greater than the first predetermined number of the reference amplitudes. A maximum likelihood estimator, connected to the equalizer, have transition states and a state transition rule which determines one of the states with respect to decision thresholds greater in number than the first predetermined number and equal to or smaller than the second predetermined number. The estimator receives the amplitude representative signal from the equalizer and perform maximum likelihood estimation on the equalizer output according to the state transition rule.
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