TM 11-6625-3041-12/TO 33A1-8-908-1
OVERVIEW OF TESTING (cont)
2-5.
MASTER : Master tim-
Timing
ing is the normal
mode and is used for
transmission paths
in which the timing
is asynchronous (not
synchronized) and
for which the 10
ppm accuracy of the
SG-1139 internal
sufficient.
STA CLK: Station clock timing is used when the accuracy of the
master oscillator is not sufficient for the path under test
(such as with the AN/TRC-170(V) which requires 0.1 ppm). This
mode can also be used to check the station clock.
LOOPED: Looped timing is used in synchronous (synchronized)
systems, such as TRI-TAC, in which the data source must be
slaved to system timing. (Individual TRI-TAC equipments, di-
vorced from the system, must use the master mode.)
2-18