TM 11-6625-3041-12/TO 33A1-8-908-1
2-5. OVERVIEW OF TESTING (cont)
Path
An acceptable path is indicated by a lit green GO BER indicator
Quality
and by a zero, or near-zero, count on the ERRORS display. Inter-
mittent errors are indicated by the count on the ERRORS display,
which increases count by only one or two at infrequent intervals.
A marginal path is indicated by a lit yellow MARGINAL BER indi-
cator and by a low count on the ERRORS display. Burst errors
are indicated by the BER indicators, which may change from
MARGINAL to NO GO to GO, to MARGINAL, etc. They are also indi-
cated by the ERRORS display which may change at a high rate one
moment, and not at all the next, etc.
A defective path is indicated by a lit red NO GO BER indicator
and by a high count on the ERRORS display. Continuous errors
are indicated by a constantly lit NO GO indicator and by the
ERRORS display, which increases count very rapidly.
Typical
Channels
Channel:
in the ATACS and
Paths
TRI-TAC system are
full duplex (they
can talk and listen
or send and receive
at the same time).
Balanced: Most
channel circuitry
uses balanced inputs
and outputs (two wires
with the signal refer-
enced or measured from
one wire or side to the
other).
Group: For trans-
mission over longer
distances, channels
are multiplexed
(combined together,
usually in groups of
4, 6, or 12, to pro-
vide a signal of a
higher rate). From
the other side, the
multiplexed (group)
signal is demulti-
plexed down to the
individual channel rate.
Because the SG-1139 must transmit and receive at the same rate,
it cannot check the input (channel rate) and output (group rate)
of a multiplexer directly. However, if the output of the multi-
plexer is connected to the input of the demultiplexer (looped
back), the combination of mux/demux can be checked.
