A possible designation of the states is "−1", "0" and "+1". It thus represents an alternative coding of a digital signal that usually has two states ( binary ), which can be designated with "0" and "1".
A ternary signal can be used to save bandwidth if the signal-to-noise ratio allows. Then the bandwidth is ideally around 67% of the bandwidth that is required for binary transmission. In practice, codes are often used that require more than this minimum bandwidth, but enable clock recovery , error detection or correction by means of channel coding .
A pseudoternary signal is used when three signal states are used, but only one binary signal is mapped onto it. In most cases, a logical "1" is transmitted as "+1", the next logical "1" as "−1".