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From: dca@edison.UUCP (David C. Albrecht)
Newsgroups: net.audio
Subject: Re: photon stylus from the past
Message-ID: <471@edison.UUCP>
Date: Tue, 23-Apr-85 13:14:37 EST
Article-I.D.: edison.471
Posted: Tue Apr 23 13:14:37 1985
Date-Received: Fri, 26-Apr-85 08:59:26 EST
References: <797@mhuxt.UUCP>
Organization: General Electric Company, Charlottesville, VA
Lines: 16

> For what its worth a fellow in my group at Murray Hill mentioned that he and
> another fellow built a "light beam" stylus in the late 50s to make a gee-whiz
> demo for a single tube 8 bit ADC (it had an internal shadow mask!) they were
> working on. He reports that the thing produced crediable sound. Tracking was
> via a non-functioning stylus as they didn't have time to build a photo-tracker.
> 
From time to time I have wondered on the practicality of using laser beams
to track a traditional record rather than a contact method stylus.  Not
knowing that much about lasers or an electronic wizard it never got beyond
pure speculation.  If it was possible to get enough reflection off the
record to accurately reproduce the cut signal maybe it would also be
possible to do a reasonable job of integrating the signal to eliminate
large excursions caused by pits, scratches, and dust.

David Albrecht
General Electric