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The basic standard

The Grand Alliance standard differs from all existing TV standards in three major ways. First, it is all digital standard - to be broadcast with a packet transmission. Second, it supports multiple formats. Third, it is designed to be primarily compatible with computers rather than existing NTSC televisions.

Summarizing the various formats:


active lines    active          aspect ratio                   frame rate in    
                horizontal                                     Hz*              
720             1280            16/9           progressive     24, 30 or 60     
1080            1920            16/9           interlaced      60               
1080            1920            16/9           progressive     24, 30

* Spectrum reports that "all the formats are supported with NTSC frame rates, 59.94Hz, 23.97 Hz, and 29.97 Hz."

Dave Marshall