Multilevel decoder-decision circuit for high bitrate ETDM transmission

An alternative to the classical binary format for ETDM transmission at high bitrate (over 20 Gb/s), the multilevel approach, is investigated. In this presentation, we deal with the reception end and compare different architectures for a multilevel decoder-decision circuit. Two designs are analysed in more details. A first realisation is presented, using an in-house InP/InGaAs 56 GHz DHBT technology; a comparison is done with a binary decision circuit processed at the same time. First conclusions about the multilevel format are presented.