S/PDIF
S/PDIF (Sony/Philips Digital Interface)[1][2] is a type of digital audio interface used in consumer audio equipment to output audio over relatively short distances. The signal is transmitted over either a coaxial cable using RCA or BNC connectors, or a fiber-optic cable using TOSLINK connectors. S/PDIF interconnects components in home theaters and other digital high-fidelity systems.
S/PDIF is based on the AES3 interconnect standard.[3] S/PDIF can carry two channels of uncompressed PCM audio or compressed 5.1 surround sound (such as DTS audio codec or Dolby Digital codec); it cannot support lossless surround formats that require greater bandwidth.[4]
S/PDIF is a data link layer protocol as well as a set of physical layer specifications for carrying digital audio signals over either optical or electrical cable. The name stands for Sony/Philips Digital Interconnect Format but is also known as Sony/Philips Digital Interface. Sony and Philips were the primary designers of S/PDIF. S/PDIF is standardized in IEC 60958 as IEC 60958 type II (IEC 958 before 1998).[5]
Applications[edit]
A common use is to carry two channels of uncompressed digital audio from a CD player to an amplifying receiver.
The S/PDIF interface is also used to carry compressed digital audio for surround sound as defined by the IEC 61937 standard. This mode is used to connect the output of a Blu-ray, DVD player or computer, via optical or coax, to a home theatre amplifying receiver that supports Dolby Digital or DTS decoding.
Limitations[edit]
The receiver does not control the data rate, so it must avoid bit slip by synchronizing its reception with the source clock. Many S/PDIF implementations cannot fully decouple the final signal from influence of the source or the interconnect. Specifically, the process of clock recovery used to synchronize reception may produce jitter.[13][14][15] If the DAC does not have a stable clock reference then noise will be introduced into the resulting analog signal. However, receivers can implement various strategies that limit this influence.[15][16]