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Posted by Bill Vermillion on 10/06/05 19:45
In article <1128472419.427285.41170@f14g2000cwb.googlegroups.com>,
Radium <glucegen1@excite.com> wrote:
>Hi:
>I fantasize about a different type of DVD technology.
Just a short comment.
>Current DVD equipment burns pits into DVD discs. The burn "marks" the
>disc with 1s and 0s. The DVD player then reads the disc. Laser light
>reflected is 1, while laser light going through the disc indicated 0s.
When the 'pits' are made the only thing that is concerned is the
transition from pit to land. These are always considered '1'. The
time elapsed between the change from pit to land is measured and
the time then computers the number of '0's for the data.
We haven't acutally written 1's and 0's on any media since the days
of FM [not MFM] modulated single density floppies that had a time
pulse between every data bit.
And nothing goes 'through' the disk. It's all related to phase
difference in the reflection of the 'pit' or the 'land'.
Bill
--
Bill Vermillion - bv @ wjv . com
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