Dynamics of analog decoders for different message representation domains

We study analog decoders in an abstract level and show that their dynamic equations can change with message representation domain. This result, which is in contrast with the behavior of conventional discrete-time iterative decoders, is derived based on continuity requirement for messages that are passed between processing nodes in analog decoders. In this letter, this requirement is met by assigning low-pass filters between processing nodes that remain unchanged for different message representation domains.