Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!oliveb!amiga!cbmvax!andy
From: andy@cbmvax.UUCP (Andy Finkel)
Newsgroups: comp.sys.amiga.tech
Subject: Re: TICK and J300
Message-ID: <6879@cbmvax.UUCP>
Date: 15 May 89 23:47:48 GMT
References: <3319@hplabsz.HPL.HP.COM> <6854@cbmvax.UUCP> <286@xdos.UUCP>
Reply-To: andy@cbmvax.UUCP (Andy Finkel)
Distribution: na
Organization: Commodore Technology, West Chester, PA
Lines: 28

In article <286@xdos.UUCP> doug@xdos.UUCP (Doug Merritt) writes:
>In article <6854@cbmvax.UUCP> andy@cbmvax.UUCP (Andy Finkel) writes:
>>Normally, the A2000 takes its 1/60sec  (or 1/50) ticks from the power
>>lines, which should be fairly accurate.  When you switch the jumper
>>to the "A500" position your A2000 then takes its ticks from the
>>video. Which is not quite as accurate.
>
>Unless there is something more going on than what you stated, this
>is inaccurate. Power line frequencies drift quite a bit, although
>the utilities usually take some care to make the drift average out to
>approximately zero over a period of time.

Exactly.  The power companies (at least the ones around here)
swear up and down that they average the power line frequency
so your clocks don't get wildly inaccurate.

When we derive the tick from the video, we are treating an
almost 1/60 sec signal as a 1/60 sec signal...which produces
a minor inaccuracy.
-- 
andy finkel		{uunet|rutgers|amiga}!cbmvax!andy
Commodore-Amiga, Inc.

  "Do or Do Not.  There is no Try." - Yoda, explaining the loop constructs
				     in JCL (Jedi Control Language).

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