D-MAC

The simultaneous PAL transmission of all TV-picture elements and the multiplexed transmission of the TV picture elements with D2-MAC.
A preview of actual D2-MAC signal. From left to right: digital data, chrominance and luminance with teletext packets between fields.

Among the family of MAC or Multiplexed Analogue Components systems for television broadcasting, D-MAC is a reduced bandwidth variant designed for transmission down cable.[1]

  • The data is duobinary coded with a data burst rate of 20.25 Mbit/s so that 0° as well as ±90° phasors are used.
  • D-MAC has a bandwidth of 8.4 MHz versus 27 MHz for C-MAC.
  • Most cable systems work on EBU 7 MHz channel spacing, so this approach did not work universally.
  • D-MAC's bandwidth problems were later fixed by D2-MAC.
  1. ^ https://www.etsi.org/deliver/etsi_i_ets/300300_300399/300355/01_60/ets_300355e01p.pdf [bare URL PDF]