# How to encode binary sequence if the number of bits are odd to e.g. 4-PAM? (Beginner)

I'm new to signal constellation and trying to understand how M-PAM works. If there is a binary sequence that has on odd number of bits and I want to send a 4-PAM signal, there will be one bit left after encoding a symbol by two bits ($$k=2$$). For example: the sequence $$1001001$$ will be encoded as $$10\rightarrow3$$, $$01\rightarrow-1$$, $$00\rightarrow-3$$ and the last bit will be by itself. How do I encode the last bit? What about 16-PAM? Will I need to express the sequence in more bits?

• start to group bits from lsb and the problem will go. in general, the problems like this are solved with communication protocol – V.V.T Sep 11 '20 at 10:00