A-MAC

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

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

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

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

Analog high-definition television systems
PAL, what MAC technology tried to replace
SECAM, what MAC technology 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 technology was replaced by this standard
DVB-T, MAC technology was replaced by this standard

References

Report 1074-1 - Satellite transmission of multiplexed analogue component (MAC) vision signals (PDF). ITU. 1990. p. 48.
Slater, Jim (31 December 1991). Modern Television Systems. CRC Press. pp. 76–78. ISBN 978-0-273-03122-2. Retrieved 20 June 2025.
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.
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.
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.

[1] Report 1074-1 - Satellite transmission of multiplexed analogue component (MAC) vision signals (PDF). ITU. 1990. p. 48.

[Slater-1991-2] Slater, Jim (31 December 1991). Modern Television Systems. CRC Press. pp. 76–78. ISBN 978-0-273-03122-2. Retrieved 20 June 2025.

[Lewis-1992-3] 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.

[Money-1988-4] 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.

[Schlyter-2000-5] 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.

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