| 摘要 |
The invention relates to a digital transmission system comprising a receiver, in which system a trellis-based estimation method (3) with a number of states reduced as a result of feedback (5) of at least one feedback value ( xi ) forms estimates (+E,cir a+EE ) for a received signal (r) by means of an estimated impulse response (+E,cir h+EE ) of a transmission system (1), a feedback value ( xi ) being determined from at least one estimate (+E,cir a+EE ). With reduced-state estimation methods for the digital transmission, the problem consists of the additional noise components caused by the feedback of preliminary false symbol decisions. To achieve optimum estimates (+E,cir a+EE ) for the received signal (r) despite a reduced number of states due to feedback, the receiver forms the feedback value ( xi ) from at least one intermediate value (+E,cir a+EE SDF). In digital transmission systems, the transmit symbols (a) and the estimates (+E,cir a+EE ) have the values -1 or 1 in the receiver. In the receiver according to the invention, intermediate values (+E,cir a+EE SDF) having a value in the range from -1 to 1 can be fed back, so that a better feedback value ( xi ) and thus better estimates (+E,cir a+EE ) for the received signal (r) may be achieved.
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