Description - GE 4PE350A3 Instructions Manual

EBI-6351
General
COLOR CAMERA
DESCRIPTION
The General Electric Color Camera, Model
4PC19D3, consists of fully transistorized
printed circuit boards that are secured in
place by captive screws. The control panels
are readily accessible for setup, operation,
and maintenance. A controlled optical system
of selectable filters and lenses facilitates
the pickup of live color television signals
for transmission.
Access to the boards, Plumbicons, view-
finder tube, and related circuitry, and me-
chanical components is made by lowering
the back panel, and both side panels. The
physical location of the boards and tubes
is shown in Figs. 1 through 5.
A fan is used for cooling and to exhaust
any excessive heat that may be present in
the Camera chamber.
Red indicating lights on the top front, in
the lens shroud, and rear operating panel
cue actors and operating personnel that the
Camera is on the air.
Signal Flow
Refer to Fig. 6.
A ten -to -one zoom lens is mounted on
the Camera head front panel through which
the
light from the scene to be televised
enters
the Camera. A motor -driven iris
governed by a servo amplifier regulates the
amount of light entering the lens, and a
manual gear drive focuses the lens.
The light enters
the Camera, passing
through one of eight optical filters mounted
in a detented wheel which permits a rapid
and accurate change of the filters to ac-
commodate different light conditions.
The light image is split into two segments
by the 30/70 neutral splitting prism, so that
30 percent of the light is transmitted to the lu-
minance channel and 70 percent is reflected
to the red, blue, and green channels. The lu-
minance channel is direct -imaging, whereas
the chrominance channels are color -split in
a 1:3/4 reduced -image relay system.
The first relay lens, directly in back of
the first mirror, is one focal length from
8
the image plane, which is the object to be
relayed.
Because the object is one focal
length away, the image for the first relay
lens is at infinity or parallel light.
The luminance light image is passed di-
rectly through the neutral splitting prism,
then to
the luminance Plumbicon pickup
tube, located on the right-hand side of the
Camera. The dichroic mirror and trim-
ming filters associated with the chrominance
channels, located on the left-hand side of the
Camera, shape the spectral response of the
reflected and transmitted light.
The light encounters the blue reflecting
dichroic, which allows passage of the red
and green light but reflects the blue com-
ponent upward. The blue light is reflected
to a first surface mirror, which, in turn,
reflects the blue light image into the as-
sociated second relay lens. The blue light
is shaped by a blue trimming filter mounted
in front of the second relay lens. The blue
light is then focused on the face of the blue
Plumbicon pickup tube.
After passage of the red and green light
through the blue reflecting dichroic, these
two light components encounter a neutral
splitting mirror which reflects 20 percent
of
the light downward to a first surface
mirror. The light is reflected by this mir-
ror to
its
related second relay lens. The
red component is removed, and the green
is finally shaped by a green trimming filter
mounted in back of the second relay lens.
The green light is then focused on the face
of the green Plumbicon pickup tube. The
80 -percent light component which passed
through the neutral
splitting mirror en-
counters its second relay lens. The green
component is removed, and the red com-
ponent is shaped by a red trimming filter
mounted in front of its second relay lens.
The red light is then focused on the face
of the red Plumbicon pickup tube.
Each of the four Plumbicon tubes has
its target lead feeding the resultant video
signal into its associated preamplifier, where
the amplitude is raised in level to approxi-
mately 0.25 volt.
The video output of each of the four pre-
amplifiers is fed to a corresponding inter-