Related to the above requirement, there should be no changes to the DTV Channel Allotment Table. Any changes to the table would require regulatory action, which would be a lengthy process, extending the period of uncertainty well beyond what is acceptable. The system must support portable applications. Support of mobile applications is desirable. The system must allow for a range of cost of receivers, including low cost receivers.
Hierarchical modulation is highly desirable.
This implementation should be transparent to the user to assure ease of reception. These thresholds should require successful demodulation, decoding and display in certain minimum reception environments described in terms of sensitivity, selectivity, noise immunity and operation in high level static and dynamic multipath. Broadcasters feel these voluntary thresholds would help the consumer manufacturers design and build DTV receivers to complete the RF delivery system from transmitter to display. The ATSC RF Task Force process should be concluded ASAP, but some of the suggested 'requirements' require regulatory action. Under existing law, DTV broadcasters must transmit 8-VSB signals with the defined ATSC framing structure.