Difference between revisions of "50 Hz dot clock rates"

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Latest revision as of 18:30, 22 March 2021

Main article: Dot clock rates

This table gives dot clock rate and pixel aspect ratio for several picture generators with the same 15.6 kHz by 50 Hz scan rate as PAL B/G. It assumes a 4:3 frame 52.068 microseconds wide by 288 scanlines tall.

Most picture generators' frequencies and pixel aspect ratios are much messier than the NTSC dot clock rates because of the large prime factor 64489[1] inherent in the definition of the PAL chroma subcarrier frequency from which many picture generators derive their dot clock.

Frequency Exact frequency PAR Exact PAR Devices
5.3203425 MHz 2128137/400000 Hz 1.387:1 2950000:2128137 PAL NES, Dendy-style famiclones, and Super NES: 6 pixels per 5 subcarrier cycles (per nesdev:Cycle reference chart)
7.375 MHz 59/8 MHz 1:1 1:1 Square progressive pixels at 4:3[2]
13.5 MHz 27/2 MHz 1.093:1 (i) 59:54 (i) Rec. 601 non-square pixels
14.75 MHz 59/4 MHz 1:1 (i) 1:1 (i) Square interlaced pixels at 4:3[2]


  1. "Colour Subcarrier - an overview". From Charles Poynton, ed. Digital Video and HD: Algorithms and Interfaces (2nd ed.) Morgan Kaufmann, 2012.
  2. 2.0 2.1 Chris Pirazzi. "Programmer's Guide to Video Systems". Lurkertech. Accessed 2015-11-17.