[time-nuts] 60Hz mains clocking in computers
Poul-Henning Kamp
phk at phk.freebsd.dk
Sun Dec 13 16:53:53 UTC 2009
In message <4B251964.5040808 at rubidium.dyndns.org>, Magnus Danielson writes:
>Joe Gwinn wrote:
>> The exception to this was that video generators were (and still
>> are) often locked to the AC line so that hum bars would not drift across
>> the screen.
>
>I have never seen this in any of the devices I've seen. It is certainly
>not what we do in the TV world either. Examples would be good.
This feature disappeared with color television, specifically NTSC, which
tweaked the vertical frequency just a tad lower than 60Hz.
Poul-Henning
PS: But NTSC gave us the 14.31818181.. MHz frequency, as imortalized
by the ghastly colors of the IBM CGA.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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