TM 11-6625-1668-12
(2) Bias and end distortion are generated digitally within the generator and is added to the output signal
in 1% increments up to a maximum of 49% Stop length is controlled by the combined setting of the CODE
LEVEL and CHARACTER LENGTH switches. The CHARACTER LENGTH switches extend the length of a
character from 7 to 16 bits (pare 3-7b(4)). Character release is controlled manually by the operator,
automatically by the generator or externally by an external step pulse.
(3) A crystal controlled time base is provided for operation at 12 speeds in the 37.5 to 9600 baud
range. A spare speed position is also included and requires only the addition of a crystal and the appropriate
timing division strap to operate in the above speed range (para 3-7e(1)). An external oscillator position is
provided for use with an external timing source, the frequency of which, in hertz, is 200 times the desired
operating baud rate. The amplitude of the external timing signal must be 6 volts 1 volt into an input
impedance of 6000 ohms. The generator may be synchronized to a station master clock which produces a
clock signal equal to 2 times the desired baud rate. When the generator is used in this mode, the distortion
circuits are inoperative.
(4) The high level output provides polar keying of up to 150 volts; neutral keying of up to 300 volts at
100 ma. maximum. High level loop power must be supplied from an external power supply. At speeds above
150 baud the high level output circuit assumes a steady mark condition. The low level output provides a MIL
STD-188B 6-volt polar 1-volt data output signal of 0 to 10 ma. The low level output circuits use the internal
power supply. Both high and low level outputs are isolated from logic ground. The generator may be internally
strapped to provide either a positive or negative marking sense (Factory strapped for positive mark). A MIL-
STD-188B 6-volt clock output is available from the front panel at the rate of one cycle per bit. The polarity of
the clock signal is such that the positive going transition occurs in the center of each data bit.
c. Analyzer, Signal Distortion TS-2862/ GGM-15(V). The TS-2862/GGM-15(V), which will hereafter be
referred to as the analyzer, is a completely self-contained solid-state test instrument
(1) This instrument performs three major functions; distortion analysis, distortion monitoring, and error
rate determination with the ability to define errors. The types of distortion measured are marking or spacing
bias, marking or spacing end, total peak, early and late peak, cyclic characteristic and fortuitous distortion. The
instrument is capable of measuring distortion on all transitions of a character or on individually selected
transitions within a character.
(2) Transition selection is made from a front panel control. The ability to measure distortion on
individually selected transitions of a start-stop signal permits measurement of cyclic distortion and speed error
distortion. When measuring synchronous signals, the analyzer synchronizes to M/S transitions and measures
the displacement of all S/M transitions. In the peak monitor mode of operation the nixie readout displays the
number of times the distortion measured exceeds the threshold setting of the ERROR DEFINER thumbwheel
switches. The distortion threshold (ERROR DEFINER thumbwheel switches) select from 0 to 49 % in 1 %
increments. In the error rate mode of operation, a 2047 bit pseudo-random test pattern from another analyzer
is compared with an internally operated pseudo-random pattern. The analyzer automatically synchronizes to
the received pattern on a bit and frame basis and counts the number of errors (as defined by the error definer
thumbwheel switches) in each one thousand or one million bit times; The result is displayed in a digital readout
which provides an overflow indication when the error rate exceeds 99 bits per thousand, or 99 bits per million.
The error definer allows for bit errors to be narrowly defined by comparing the logic state of the input error
signal with the state of an internally generated perfect pseudo-random test message. If the input signal is
distorted or if a bit is not in coincidence with the internal perfect pattern an error is detected. A built-in error test
mode is provided which is implemented when the analyzer is used with its companion Signal Generator SG
860/ GGM-16(V) in order to self-check the error rate and error defining functions of the analyzer.
(3) A crystal controlled time base is provided for operation at 12 speeds within the 37.6 to 9600 baud
range. A spare speed position is also furnished and requires only the addition of a crystal and the proper
strapping to operate the unit at the desired speed range. An external oscillator position is provided for use with
an external timing
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