A-MAC

  1. Home
  2. Wiki

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

In television electronics, A-MAC is a form of analog video encoding, specifically a type of Multiplexed Analogue Components (MAC) encoding.[1] It carries digital information: sound, and data-teletext on an FM subcarrier at 7 MHz. Since the vision bandwidth of a standard MAC signal is 8.4 MHz, the horizontal resolution on A-MAC has to be reduced to make room for the 7 MHz carrier.[2] A-MAC has not been used in service.[3]

Technical details

[edit]

MAC transmits luminance and chrominance data separately in time rather than separately in frequency (as other analog television formats do, such as composite video).[4]

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.[5]

TV transmission systems

[edit]

References

[edit]
  1. ^ Report 1074-1 - Satellite transmission of multiplexed analogue component (MAC) vision signals (PDF). ITU. 1990. p. 48.
  2. ^ Slater, Jim (31 December 1991). Modern Television Systems. CRC Press. pp. 76–78. ISBN 978-0-273-03122-2. Retrieved 20 June 2025.
  3. ^ Lewis, Geoffrey E. (1992). Communication Services Via Satellite: A Handbook for Design, Installation and Service Engineers. Elsevier Science & Technology Books. p. 238. ISBN 978-0-7506-0437-6. Retrieved 20 June 2025. A-MAC has not been adopted.
  4. ^ Money, Steve A. (1988). Newnes Radio Amateur and Listener's Pocket Book. Pearson Education New Zealand Limited. p. 75. ISBN 978-0-434-91259-9. Retrieved 20 June 2025. In the multiplexed analogue components (MAC) system the luminance and chrominance signals are transmitted separately by using a time multiplexing system.
  5. ^ Schlyter, Paul (12 November 2000). "Multiplexed Analogue Components in 'Analog TV Broadcast Systems'". Archived from the original on 22 February 2025. Retrieved 20 June 2025.


Stub icon

This article about television technology is a stub. You can help Wikipedia by expanding it.