# Manchester decoding

Is there any method of decoding a Manchester encoded signal (IEEE 802.3) that is independent of the bit period?

Suppose the data I want to send is $\rm 10110$. The Manchester code of this data will be $\rm 0110010110$ (according to IEEE standard). We can see that in the $\rm 0101$ part, we need to consider the $\rm 0 \rightarrow 1$ transition (to decode a $\rm 1$) and not the $\rm 1 \rightarrow 0$ transition (falsely decoding a $\rm 0$). To do this, we need to know the bit period a priori.

My question is, is there a way to do this without knowing the bit period a priori?

I think what you're really asking is whether you can decode a Manchester-encoded bit stream without being synchronized to a frame boundary. As you noted, a mid-symbol transition from $0$ to $1$ indicates one state (i.e. a transmitted $1$ for instance), while a transition from $1$ to $0$ would indicate the opposite state (a transmitted $0$). You seem to want to decode a Manchester-encoded bit stream without necessarily knowing where the symbol boundaries are.
\begin{align} \text{received 01} &\to \text{1 transmitted} \\ \text{received 01} &\to \text{1 transmitted} \\ \text{received 00} &\to \text{invalid!} \\ \text{received 11} &\to \text{invalid!} \\ \end{align}