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APPENDIX E:
Field Alignment Procedure
1: GENERAL
The
following section describes how to align and calibrate OPTIMOD-TV in the
field.
It is included primarily for purposes of reference as routine alignment is
neither
necessary
nor
desireable
due
to
the
high
stability
of
the
circuitry.
WARNING!
IF
CALIBRATION
IS
NECESSARY,
WE
STRONGLY
RECOMMEND
THAT THE CARD IN QUESTION BE RETURNED TO THE FACTORY
FOR
CALIBRATION
BY
OUR
EXPERIENCED
TECHNICIANS,
WHO
HAVE
ACCESS TO SPECIAL TEST FIXTURES AND A SUPPLY OF
EXACT- REPLACEMENT SPARE PARTS. ONLY IN AN EMERGENCY
SITUATION
SHOULD
AN
ATTFMPT
BC
MADF
TO
ALIGN
AND
CALIBRATE OPTIMOD-TV IN THE FIELD.
The factory aligns each card independently to a standard, so that cards will be
completely
interchangeable.
However,
the
user
does
not
have
access
to
the
special
test fixtures necessary to complete independent alignment of the cards.
The user thus must use his own OPTIMOD-TV chassis as a test fixture, and align
the entire unit as a system.
This section is organized on a card- by- card basis. Cards should be calibrated in
the same order as their order in the signal path, from input to output. This will
occur
naturally
if
the
instructions
in
this
section
are
followed
in
order
from
beginning to end. If a card later in the signal path is aligned while an earlier
card
is
misaligned,
the
later
card
may
not
be
correctly
aligned,
even
if
the
instructions for that card are followed conscientiously.
Before
commencing
alignment,
remove
OPTIMOD-TV
from
its
normal
rack
mounting location and place it on the test bench away from RF
fields. Jumper
the
chassis
and
circuit
grounds
together
on
the
rear- panel
barrier
strip.
2: REQUIRED TEST
The
following
test
equipment ( or
close
equivalents)
is
required.
It
is
assumed
EQUIPMENT AND
that
the technician is thoroughly familiar with the operation of this equipment.
MATERIALS
a) Digital Voltmeter, accurate to + 0.1%
b) Oscilloscope, DC- coupled, dual- trace, triggered- sweep,
vertical bandwidth
c) Ultra- Low
Distortion
Sinewave
Oscillator/THD
Test
Technology 1700B or 1710B)
d)
Low
Frequency
Spectrum
Analyzer
with
Tracking
5L4N plug-in with 5111 Bistable Storage Mainframe)
e)
A 137K 1% resistor
f)
A 243K 1% resistor
g) Six 6" alligator- to- alligator jumper leads
h)
A luF + 20% film capacitor ( voltage unimportant)
with 5mHz or better
Set/AC
VTVM ( Sound
Generator ( Tektronix
E-1
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