TM 11-6625-1668-12
(8) Typical operation PEAK MON. For the purpose of this procedure assume the following input signal
parameters: high level, neutral, 130 volts 60 milliamperes 5 level start stop code, 150 bauds. 30 percent
distortion negative mark. Initial analyzer control settings are listed below.
Control
Position
Control
Position
POWER switch..................................
OFF
ERROR DEFINER thumbwheels ..........
25
MARK POLARITY switch ...................
----
CODE LEVEL switch............................
5
RESET switch ...................................
OFF
INPUT switch .......................................
60N
DISPLAY MODE switch .....................
PEAK MON
BAUD RATE switch..............................
150
NOTE
The position of unmentioned controls will not affect operation in this mode.
(a) Connect the external data signal to the analyzer SERIES INPUT jack.
(b) Set POWER switch to ON and reset the nixie display.
(c) Read hits on the nixie display and note that the nixies display a rapid count. The rapid count
indicates that distortion on the input data signal exceeds the threshold setting of 25 percent. The overflow lamp
will illuminate when the total hit counted exceeds 99.
(d) Increase the setting of thumbwheels in one percent increments until the nixies no longer
display a rapid count. Note that the thumbwheel setting is approximately 30 2 percent.
(e) Reset the nixie display and note that with the threshold set at 30 percent hits are seldom
counted.
c. Distortion Measurements.
(1) AVERAGE BIAS S/M. Bias distortion, as measured by the analyzer is the average displacement of
the S/M transitions from the correct positions. Marking bias is the result of a lengthened mark interval
(transition occurs early, while spacing bias is the result of lengthened space interval; transition occurs late).
Bias distortion is measured when the DISTORTION switch is set to AVERAGE, BIAS, S/M. The amount of bias
is displayed on the nixie readout with marking or spacing bias indicated when the MARK or SPACE lamp
illuminates. A signal containing zero distortion and operating at the same speed as the analyzer will cause the
nixie display to read zero and the MARK and SPACE lamps to blink alternately.
(2) AVERAGE END M/S. End distortion as measured by the analyzer is the average displacement of
the M/S transitions relative to the first M/S transition (start pulse). The distortion is called marking end if the
mark interval of the first intelligence bit is lengthened (transition occurs late) and spacing end if the resulting
space interval is lengthened (transition occurs early). AVERAGE, END M/S. The amount of end distortion is
displayed on the nixie readout with marking or spacing end indicated when the MARK or SPACE lamp
illuminates.
(3) PEAK TOTAL. The total peak distortion as measured by the analyzer is the highest amount of
distortion of any type occurring on the signal during the period of measurement. The distortion may occur on
M/S (mark-to-space) or S/M (space-to-mark) transitions, either early or late. A single transition is sufficient to
give the peak distortion with full accuracy. The reading will be maintained on the nixie display until changed by
a higher reading or reset to zero. The total peak measurement is made when the DISTORTION switch is set to
PEAK TOTAL. The RESET switch is used to reset the nixie display in order to obtain a new reading which is
lower than that maintained on the nixie display. Since the total peak distortion is measured on both M/S and
S/M transitions simultaneously and the definition of marking and spacing distortion changes with the type of
transition the MARK and SPACE lamps are made inoperative.
(4) PEAK EARLY, LATE. When the DISTORTION switch is set to PEAK EARLY the analyzer
measures the maximum distortion of both M/S and S/M transitions occurring earlier than the correct time.
When the DISTORTION switch is set to PEAK LATE the analyzer measures the maximum distortion of both
M/S and S/M transitions occurring later than the correct time. The ability to display separately early and late
peak distortion, enables the operator to measure the maximum amount of random fortuitous distortion
prevalent when transmitting teletype over radio circuits.
d. Transition Selection. The analyzer will measure distortion for any one or all transition times in a start-
stop character. With the TRANSITION switch set to ALL and the DISTORTION switch set to BIAS, S/M the
distortion is measured on all S/M transitions in the character. With the DISTORTION switch set to END, M/S
the distortion is measured on all M/S transitions except for the start bit. When the DISTORTION switch is set
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