Considerations When Designing for the SMPTE 424M Interface
When SMPTE 424M, the standard for a 3 Gbit/sec serial digital interface (SDI) was introduced, much of what was standardized was similar to the HD-SDI interface that is so well established and understood. The assumption of many early adopters of this standard was that the same architectures used to build 3 Gbit/sec equipment could be used for HD-SDI, and then studios could be built with this equipment in order to support the higher definition formats. Unfortunately, when SMPTE 424M was approved, it included a relaxed jitter specification, allowing up to 0.3 unit interval (UI) of alignment jitter rather than the 0.2 UI, which is permitted in SMPTE 292M—the HD-SDI specification. This paper explores the consequences of this relaxed specification on system performance and looks at new architectures for studio equipment that are able to better tolerate the increased jitter. The fact that studio designers may want to look more closely at some performance measurements of 3 Gbit/sec equipment rather than just looking for SMPTE 424M compliance is also discussed.
- Print ISSN
- 1545-0279
- Electronic ISSN
- 2160-2492
- Published
- 2009-05
- Content type
- Original Research
- DOI
- 10.5594/J14943