In an example embodiment, a signal processor is disclosed that is configured to decode a clock-first, change-on-zero differential Manchester encoded data stream. The data stream has no local clock, and both combinatorial and sequential logic is used to decode the stream into a clocked data signal and an optional error signal. Decoding comprises a parser that separates the input data stream into an intermediate data signal, an intermediate clock signal, and a conditioning signal. A data and error generator receives the three signals and outputs a clocked data signal and a clocked error signal.