DTTB Spectrum Mask Base
Based upon DCA Comms. Laboratory subjective testing using the SCM40 method for vision interference levels and a deduction from the LOP method for sound interference levels.
Adjacent channel operation with matching coverage patterns of DTTB and PAL, transmitted from the same area.
DTTB to PAL ratio of -10 dB required for adjacent channel protection of PAL from DTTB.
The DTTB side bands are required to be 45 dB below PAL vision to protect PAL.
The mask is conservative allowing for the introduction of DTTB into a 100 % PAL market.