The 1920x1080/60i HDTV format
May 1, 2003 12:00 PM
The picture scanning characteristics
 Table 1. Picture scanning characteristics of the 1920x1080/60i format are listed above. |
Table 1 shows that the 1920x1080/60i format has a nominal frame rate of 30Hz or 30/1.001Hz (NTSC-friendly). Each frame consists of two interlaced fields with an interlace ratio of 2:1, resulting in a field rate of 60Hz, or 60/1.001Hz for NTSC-friendly applications.
There are a total of 1125 lines per frame. In an analog system this would imply 562.5 lines in each field. However, because a digital interface has to be supported, only whole numbers of lines in each field are allowed. This permits the unambiguous identification of the lines by the digital timing reference sequences (TRS). As a consequence, the interlace versions define integer, and hence unequal, numbers of lines in each of the two fields comprising a frame. Field 1 has 563 lines and Field 2 has 562 lines. The horizontal scanning frequency is 33750Hz. It is interesting to note that this format uses analog sync signals that differ from those used by SDTV formats. The analog sync signals are not digitized, so they are rarely, if ever, encountered in practice. The reader is referred to the relevant SMPTE or ITU standard for details.
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