Demapper for a quadrature amplitude modulation - / trellis modulation - decoder and operation based thereon

摘要

A demapper, which in the case of a quadrature amplitude modulation / trellis modulation (qam - tcm) - decoder is applied to more significant bits of a qam - signal according to the qam - signal and at least one low significant bit of the qam - signal to produce, is disclosed. The demapper comprises a slide for the displacement of the qam - signal, in order to produce a shifted signal; a threshold comparison - and mapping unit for outputting at least of a buffered value of most significant bits; a sign bit - decision element for determining a sign value corresponding to the offset signal; a multiplexer for generating a first determination of a higher-order bits and a second determination of a higher-order bits and a processing unit for determining a third determination of a higher-order bits and a fourth determining a most significant bits.