GE 4PE350A3 Instructions Manual page 281

TUBE TYPES XQ10201,X01020R,X01020G,X431020B
FOOTNOTES
1)
For focusing/deflecting coil assembly, see "Accessories".
2)
For proper orientation -of the image on the photo -conductive layer the vertical scan should be essentially
parallel to the plane passing through the tube axis and the mark on the tube base.
3) As measured under following conditions:
Tubes are exposed to 0. 45 ft. C. illumination of black body color temperature of 2850° K. The appropriate
filter is inserted in the light path (XQ1020R, G, B). The signal current obtained in nano -amperes denotes
the color sensitivity expressed in terms of micro -amperes per lumen of white light before the filter.
4)
5)
6)
7)
8)
9)
10)
11)
12)
13)
Filters Used:
XQ102OR Schott
0G2 (Thickness
3mm)
XQ1020G Schott
VG9
(Thickness
1mm)
XQ1020B Schott
BG12 (Thickness 3mm)
Gamma is, to a certain extent, dependent on the wavelength of the illumination applied. The use of Gamma -
stretching circuitry is recommended.
The capacitance of the target to all electrodes, which effectively is the output impedance, increases when
the tube is inserted into the deflecting/focusing assembly.
Underscanning of the specified target area of 0. 5 in. x 0. 67 in. or failure of scanning, should be avoided
since this may cause damage to the photoconductive target.
With no blanking voltage on Grid No.
1.
At cathode voltage = 0 volts
A minimum of 1 minute warm-up time for the heater is to be observed before drawing cathode current.
For short intervals, during storage and idle periods of the camera, the tube -face shall be covered with the
plastic hood which is provided.
The signal electrode voltage shall be adjusted to 45 volts. To compete with excessive highlights in the
scene to be televized, the signal electrode voltage may be reduced to a minimum of 25 volts.
This will
however result in some reduction in performance, especially in respect to sensitivity.
The beam current shall be adjusted for correct stabilization of a highlight signal current of twice the
amount as indicated in the table below.
Focus Line Frame
Current Current
Current
mA
mA pp mA pp
Black/White Coil Assembly AT1132
Grid No. 3 Voltage = 50-100 V
Grid No. 4 - Grid No. 3 = 50-100 V
25
235
35
Color Coil Assemblies AT1112
AT1113
Grid No. 3 Voltage = 600 V
Grid No. 4 - Grid No. 3 = 50-100 V
100 235
35
14)
15)
approx.
values
The optimum voltage difference between grid No. 4 and grid No. 3 is depending on the type of focusing/
deflecting coil unit used.
For types AT1112, AT1113, AT1132 a voltage difference of 50 to 100 Volt is recommended.
Faceplate illumination level for the XQ1020 and XQ1020L typically needed to produce 0. 3 µ A signal current
will be approx. 0.4 ft. C. The signal currents stated for the color tubes XQ1020R, G, B respectively will
be obtained with an incident light -level (2850° K) on the filters of approx. 1. 0 ft. C. The figures stated for
modulation depth are based on the use of the filters described in note 3, for filter BG12 however a thickness
of lmm is chosen.
illumination on the photo -conductive layer, Bph, in the case of a black/white camera is related to scene
-
illumination, Bsc, by the formula:
Bph = Bsc
R. T.
4F2 (m + 1)2
in which R represents the scene -reflexivity (average or the object under consideration, whichever is
relevant), T the lens transmission factor, F the lens aperture and m the linear magnification from scene
to target.
A similar formula may be derived for the illumination level on the photoconductive layers of the respective
R, G, and B tubes in which the effects of the various components of the complete optical system have been
taken into account.
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