Compatible CED VideoDisc Players - RCA SJT-400
RCA SJT-400 - Service Manual (76 pages)
RCA SJT-400 - Service Manual Addendum (2 pages)
CED VideoDisc Information - CED stands for Capacitance Electronic
Disc, which refers to the method used to encode the video and audio information
on the disc surface. Capacitance can be defined as the ability of two adjacent
conductors to store electric charge, and in the CED system these adjacent
conductors are the carbon-loaded disc and the thin titanium electrode deposited
on the diamond stylus. The mathematical formula for capacitance contains several
variables, but with the CED system these variables are all constant except
one... the distance between the electrode and the surface of the disc
immediately under it. Within the grooves on the disc surface are microscopic
peaks and valleys, several times smaller than the diamond stylus, which rides
smoothly on the crests of several adjacent peaks. But the electrode is much
smaller than the stylus, so the distance between the electrode and disc surface
is constantly changing as peaks and valleys pass underneath. This varying
distance produces a varying capacitance, from which the audio/video signals are
eventually decoded by the player's signal processing circuitry. For more
information on this CED VideoDisc player, check out
Tom
Howe's CED FAQ on his
CED
Magic website.
