used in South Africa by Multichoice, Australia by Optus. Used in the US by Primestar and American Forces Radio and Television Service. Used in parts of Asia until 2005 when it was replaced by digital compression. C-MAC required a bandwidth of about 22 MHz, making it problematic for broadcasting. It could carry eight high quality (15 kHz bandwidth) sound channels. It has a wide-screen backwardly compatible variant called E-MAC. D-MAC was a UK standard (used by British Satellite Broadcasting) for satellite broadcasts, needing a bandwidth of approximately 10.5 MHz. It could carry eight high quality (15 kHz bandwidth) sound channels Used in Norway by NRK, transmitting 3 radio channels and 1 TV channel at one D-MAC channel. D2-MAC further reduces the bandwidth to 7.8 MHz allowing usage on cable and satellite broadcast. It could carry four high quality (15 kHz bandwidth) sound channels or eight lower quality audio channels. Adopted by Germany and France, it was used on satellite broadcasts (TV-Sat 2, TDF 1 and TDF 2). The system was used until July 2006 in Scandinavia and until the mid-1990s for German and French sound channels. Some cable systems may still be using D2-MAC in Europe and Asia. HD-MAC, an early high-definition television standard allowing for 2048x1152 resolution. Studio (non-broadcast) MAC variants S-MAC (Studio MAC): Used mostly in North America. Processing NTSC component signals yields better results (a higher quality image) than manipulating NTSC directly – thus the need to create S-MAC. It is not possible to mix standard MAC signals in the studio environment because the (R-Y) and (B-Y) components are carried on alternate lines. S-MAC's SECAM like approach to bandwidth reduction is technical annoyance, but most studio users are not affected by it. In S-MAC the luminance is compressed by 2:1 and the two chrominance signals by 4:1 so that all three may occupy the same line. S-MAC's vision bandwidth is 11 MHz, only ~2.8x that of NTSC's vision bandwidth of 4.2 MHz. S-MAC can be carried on a single circuit and converted losslessly to and from C-MAC at any stage. S-MAC is well suited for SNG applications (AKA: news gathering trucks). Technical overview MAC transmits luminance and chrominance data separately in time rather than separately in frequency (as other analog television formats do, such as composite video). This allows for full separation of the components. The signals are also time-compressed (with ratios of 3:2 for luminance and