ABSTRACT
The SDI link carries uncompressed SD video at 270-Mb/s line rates. Interestingly, the SDI link can synchronously carry a digitally sampled 625/25 line structure signal (used in the PAL system) or the 525/29.97003 line structure signal (used in NTSC systems) at the same line rate of 270 Mb/s. How is this possible as the two TV systems have apparently unrelated sampling rates? History records that the 525 and 625 analog systems were developed independently of each other. However, the two digital systems have a common sampling rate of 270 Mb/s. Let us see why.
