Phase shaped binary transmission

The PSBT (Phase Shaped Binary Transmission) is a type of modulation format for digital transmissions.

It is most commonly used in optical systems (WDM and OTDM) because of its increased tolerance to chromatic dispersion and reduced bandwidth occupation, with respect to the typically used NRZ scheme.

It is derived from the duobinary format, and is characterised by a phase-shift of π radians between a transition from binary "0" (space) to "1" (mark), and vice versa.