As the other main member of the Bipolar scheme family, the Bipolar Pseudoternary scheme shares the same main idea regarding binary line coding, that is: one of the possible bit values is represented by a null voltage, and the other one by a non-null voltage level that alternates between positive and negative voltage levels.
The only difference between this scheme and the Bipolar AMI one is that the Pseudoternary encoding uses the exact opposite coding logic to the AMI encoding. Such coding logic is shown below.
- Bit 0: voltage alternates between positive and negative (+V and -V).
- Bit 1: voltage is zero (0V).
Just like with its brother scheme, the Pseudoternary scheme can mantain a good level of clock synchronization -although, unlike AMI, this happens when there's a majority of 0s transmitted, because of the transitions that occur when they're encoded-. However, this ability is not as present as in other types of schemes (e.g., Manchester-style coding schemes), for large sequences of 1s can lead to loss of synchronization due to the lack of transitions.
Below is a small set of examples of the Bipolar Pseudoternary scheme.
