D-MAC

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The simultaneous PAL transmission of all TV-picture elements and the multiplexed transmission of the TV picture elements with D2-MAC.

Simulated MAC signal. From left to right: digital data, chrominance and luminance

D-MAC is a reduced bandwidth variant designed for transmission down cable.

• The data is duo-binary coded with a data burst rate of 20.25Mb/s so that 0° as well as ±90° phasors are used.
• D-MAC has a bandwidth of 8.4MHz versus 27MHz for C-MAC.
• Most cable systems work on EBU] 7MHz channel spacing, so this approach did not work universially.
• D-MAC's bandwidth problems were later fixed by D2-MAC.

[edit] D2-MAC: A fix for D-MAC

D-MAC consumed too much bandwidth for many applications, so D2-MAC was devised for European cable TV systems.

[edit] MAC FAQ

MAC transmits luminance and chrominance data separately in time rather than separately in frequency (as other analog television formats do, such as composite video).

Audio and Scrambling (selective access)

• Audio, in a format similar to NICAM was transmitted digitally rather than as an FM subcarrier.
• The MAC standard included a standard scrambling system, EuroCrypt, a precursor to the standard DVB-CSA encryption system.

[edit] See Also

Weblinks

• Multiplexed Analogue Components in "Analog TV Broadcast Systems" by Paul Schlyter

TV transmission systems

• Analog_high-definition_television_systems
• PAL, what MAC technolgy tried to replace
• SECAM, what MAC technolgy tried to replace
• A-MAC
• B-MAC
• C-MAC
• D-MAC
• E-MAC
• S-MAC
• D2-MAC
• HD-MAC, an early high-definition television standard allowing for 2048x1152 resolution.
• DVB-S, MAC technolgy was replaced by this standard
• DVB-T, MAC technolgy was replaced by this standard

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