ATSC M/H Sub-Frame [EtherGuide Glossary]
An ATSC M/H Sub-Frame is a conceptual element that is comprised of 4 8-VSB data frames and which encompasses 193577585.4 nanoseconds, which is usually rounded up to 193.6 milliseconds. There are 5 M/H Sub-Frames in each ATSC M/H Frame. Each M/H subframe encompasses exactly 16 ATSC M/H slots.
The diagram below illustrates the relationships between an ATSC M/H Sub-Frame, 8-VSB data frames and ATSC M/H slots.
Each ATSC M/H Sub-Frame contains the equivalent of 2,496 MPEG-2 packets (3,753,984 bits), and if ATSC M/H data is present in the Sub-Frame, contains at least 608 packets (914,432 bits) carrying main (MPEG-2) packets. In any ATSC M/H subframe where M/H data is present, as many as the equivalent of 1,888 MPEG-2 packets (2,839,552 bits) carrying ATSC M/H data may be present, depending on arrangement.