TM 11-6625-1668-12
Control
Position
Control
Position
CHARACTER LENGTH switch .........
8
ALARM switch..................................
DISABLE
SINGLE switch ................................
(Not used)
BAUD RATE switch..........................
1200
OSC switch .....................................
INT
(a) Connect a patch cord from the DATA 6V OUTPUT jack of the generator to the BRIDGING
INPUT jack of the analyzer.
(c) The analyzer nixie display will indicate 25% l% and the MARK lamp will illuminate to indicate
marking bias.
(d) Change the PERCENT DISTORTION switch on the generator to 20%; the analyzer nixie
display will indicate 20% 1% and the MARK lamp will illuminate to indicate marking bias.
b. Analyzer Modes of Operation. The analyzer is designed to provide four modes of operation; TEST
MODE, DISTORTION, ERROR RATE, and PEAK MON.
(1) Test mode. The analyzer, when operated in conjunction with the generator, will produce a pseudo-
random test pattern. This test pattern is applied to the generator through the rear panel connector and back to
the analyzer for system self-test. The system self-test is performed as part of the maintenance procedures.
This function is accomplished when the analyzer DISPLAY MODE switch is set to TEST MODE and when the
generator MESSAGE SELECT switch is set to EXT. The BAUD RATE switches of both units must be the same
and the interface cable CX-12024/GGM-15(V) must be connected. Refer paragraph 4-8 for a detailed
explanation test mode operation.
(2) Typical operation TEST MODE. The purpose of this operating procedure is to test the analyzer
error code operation. To perform the error test operation a generator (SG-860/GGM-15(V)) is required and
must be connected to the analyzer through the interface cable. The initial control settings of the generator and
analyzer are listed below.
Control
Position
Control
Position
POWER switches (analyzer and
OFF
MARK POLARITY switch (analyzer) .....
.....................
generator).
DISTORTION SELECT switch
NO DIST
RESET switch (analyzer)......................
OFF
(generator).
MESSAGE SELECT switch
EXT
DISPLAY MODE (analyzer) ..................
TEST MODE
(generator).
BAUD RATE switches (analyzer and
120
ERROR DEFINER thumbwheels ..........
49
generator).
NOTE
The position of unmentioned controls will not effect error test operation.
(a) Set the POWER switches (generator and analyzer) to ON.
(b) Depress the RESET switch to MAN and release it. Read approximately 10 errors every 9
seconds and note an overflow indication after 98.
(c) Set the generator DISTORTION SELECT switch to BIAS M and the PERCENT DISTORTION
switches to 25.
(d) Reduce the setting of the ERROR thumbwheel switches to the point where the nixies display a
rapid count.
(e) Read the amount of distortion on any M/S or S/M transition as indicated by the number on the
thumbwheel switches.
(3) DIST (%). The analyzer is used to measure distortion on data or telegraph signals when the
DISPLAY MODE switch is set to DIST (%). Distortion, as measured by the analyzer is defined as the time
displacement of a signal transition from its theoretically correct position. The transition is taken as the half-
current point, for neutral signals and is the zero current crossover point for polar signals. The analyzer is used
to measure bias, end, total, early and late peak distortion. Characteristic, fortuitous, and speed-error distortion
are determined from these measurements. When making an analysis the operator should first determine the
baud rate, type of signal (polar or neutral) current level, and operating mode (start-stop or synchronous). The
amount of bias and end distortion is read directly on the nixie display while the MARK and SPACE lamps
indicate the type. When total-early or late-peak measurements are made the MARK and SPACE lamps are
inoperative. However, an early-peak reading indicates the presence of marking distortion and a late-peak
3-15
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