Multiplexed Analogue Components (MAC) is a satellite television transmission standard, originally proposed for use on a Europe-wide terrestrial HDTV system, although it was never used terrestrially. 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 was transmitted digitally rather than as an FM subcarrier.

A number of variants existed - A-MAC, B-MAC, C-MAC, D-MAC (used by British Satellite Broadcasting), D2-MAC (used to this day in Scandinavia and at the beginning of the 1990s for German and French satellite television) and HD-MAC, an early high-definition television standard allowing for 2048x1152 resolution. The MAC standard included a standard scrambling system, EuroCrypt, a precursor to the standard DVB-CSA encryption system

D-MAC satellite broadcasts provided the first broadcast sourced widescreen television in Europe, and HD-MAC provided the first HDTV broadcasts, in 1992.

Although the MAC technique is capable of superior video quality, (similar to the improvement of component video over composite in a DVD player), its major drawback was that this quality was only ever realized when the video signals being transmitted remained in component form from source to transmitter. If at any stage the video had to be handled in composite form, the necessary encoding/decoding processes would severely degrade the picture quality.

Since the vast majority of TV stations and similar installations were only wired for composite video, the fitting of a MAC transmitter at the end of the chain had the effect of degrading the transmitted image quality, rather than improving it.

For this and other reasons, MAC systems never really caught on with broadcasters, and were finally made obsolete by the radically new digital systems introduced in the mid- 1990s

External link

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

MAC-Verfahren | Satellite television