Re: Life after CDs

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Article #1505

#1505

From: Tony Duell
Date: Sun, 02 Aug 1992 17:12

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The laser pick-up is scanned across the disk in 2 ways:
1) The Philips radial tracking arm - the laser is mounted on a pivoted arm
which is rotated by 'a moving coil meter'. This type scans continuously.
2) The laser is driven by a DC motor and gearbox. Because the disk is not
perfectly central , it is necessary to alow the laser to move slightly on
the disk, and this is done by a second tracking system, again a moving
coil meter. When the disk is played, the second system follows the track,
and when it gets towards the end of its range, the DC motor moves a bit,
and the moving coil continues tracking. Thats why it seems to step
-tony 'PDP11 Hacker' Duell
ard@siva.bris.ac.uk

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References: <27JUL199209444686@erin.caltech.edu> <1992Jul30.112024.14197@

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Newsgroups: sci.electronics,rec.audio,alt.folklore.computers
Path: arc1-ca.pugleaf.net!sparky!uunet!mnemosyne.cs.du.edu!nyx!aduell
From: aduell@nyx.cs.du.edu (Tony Duell)
Subject: Re: Life after CDs
Message-ID: <1992Aug2.171205.1569@mnemosyne.cs.du.edu>
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References: <27JUL199209444686@erin.caltech.edu> <1992Jul30.112024.14197@
Date: Sun, 2 Aug 92 17:12:05 GMT
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