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(1) Bunker-Ramo 133/141 Computer System - This data
processing system consists of a BR 133 computer, a BR 141 con-
troller and an IBM Selectrate Typewriter I/O unit. The
computer utilizes stored logic techniques with 16,384 (15 bit)
word magnetic core memory with a two microsecond read-write
cycle to provide nondestructive memory. The BR 141 controller
provides paper tape punching and photoelectric paper tape
punching (tape duplication) and photoelectric reading capabilities
for entering data into the computer and for preparing data
tapes. The IBM Selectrate Typewriter is used principally
off-line for the preparation and double checking of data tapes.
(2) Scanning/Printing Tables - The scanning and
printing tables are four identical units consisting of a base
assembly, a modular CRT unit for interchangeable scanning
or printing, a multi-element focusing lens assembly, a
Ferranti measuring system, a l2-stage photomultiplier with
integral preamplifier and X-Y carriages with ball-nut lead
screw drive assemblies. Figure 12 shows an artist's sketch,
including a cutaway view of the table.
a. Base Assembly - The base is a built up
assembly 49 x 76 x 50 inches providing a rigid, stable platform
free from influence of external mechanical disturbances.
b. Modular CRT Unit - The CRT housing is
incorporated into the base assembly in a removable package.
It consists of a 5ZP16 CRT as the controlled light source,
and the associated operating elements.
c. Imaging Lens - The imaging lens is a 24
millimeter fixed focus unit adjusted to produce a nominal 20
to 1 reduction with an image to object distance of 21 inches.
d. Measuring System - The measuring system is a
Ferranti, Moire-fringe detecting device. Each measuring system
is comprised of a precision grating and reading element ( a
short grating), a collimated light source and photocell trans-
ducers with preamplifiers. The resolution (least counting
increment) of the system is two microns.
e. Photomultiplier - The photomultiplier tube
is a l2-stage light to electrical signal transducer sensitive
to the band of wave lengths emitted by the 5ZP16 CRT phosphor
(3500 to 4500 angstrom units).
f. Carriages - Two independent carriages
provide motion for positioning the diapositives or photosensitive
film sheets. The antifriction ways, v-grooved, which are signi-
ficant in obtaining good orthophoto quality, are fitted with
gauged 3/4 inch ball bearing trains. The X and Y carriages are
each driven by a gear train through gimbaled ball-nut lead
Screws.
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