🚀 go-pugleaf

In article <3385@ncrcae.Columbia.NCR.COM>, wte@ncrcae.Columbia.NCR.COM (Bill Eason) writes:
> When I asked about the number of lasers tracking (something most ads hype),
> the salesman told me that CD player makers "...found that the number of lasers
> really didn't make any difference in how well the disc was tracked."  By
> the time that sentence got past my ears, it sounded more like "We don't carry
> any models with that feature."  What do netters think?

As far as I know, all CD players have only one laser.  In 3-beam players,
the laser beam is split into 3 beam before reflecting off the disc.  In single-
beam players, the beam is split after reflecting off the disc.  In either
case one signal is used for data and the other two beams are used for 
tracking and focus correction.  Both systems work, but the single beam system
has the advantage of simpler design and fewer parts to get out of alignment.
I don't know of any advantage of a 3-beam system, except "ad hype" 
--
Don Gentner			Electronic mail:
Philips Laboratories		  gentner@philabs.philips.COM
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