Tektronix TG8000 User Manual

GPS7 GPS Synchronization and Timecode module
This antenna in
formation is not intended to cover all aspects of the antenna system
design. Important topics that were not covered include items like lightening
protection and drip loops. For information about the cable plant design in your
system, contact the appropriate person or group in your organization, or contract
with a qualified installer.
Figures of M erit (FOM)
These numbers are a compendium of the GPS/GLONASS signal quality and the
processes that occur as the instrument progresses through the states needed to lock
on to the GPS/GLONASS signal. The FOM provides a simple scale to evaluate
the state of the G PS/GLONASS lock.
The FOM drives the external r eference indicator (LED) on the front panel of the
mainframe. When in internal mode, the external LED is off. When in external
mode and the FOM is ≥ 6, the LED is steady green. When the FOM is < 6, the
LED is flashing green.
The FOM provides the scale by which you can set the signal warning threshold.
(See page 3-151, GPS7 module GPO submenu.)
You can see the description of the FOM in the GPS7 STATUS menu. The
following table lists the figures of merit and their descriptions.
Table 3-19: Figures of merit for signal quality
Figure
of merit
(FOM) Indicator Description
0 No signal This means that no usable satellite signals are
detected. This is normal for a short time after
the signal is applied, but if it lasts more than a
minute or so, then it usually means one of the
following: that there is a problem in the antenna
or cable, the antenna is blocked from direct line
of sight to the satellites, or the power is not
getting to the antenna.
1 Low signal This means that some signal is detected, but
that the signal quality is too low for extraction
of useful timing or position information. This is
a normal situation for a short duration, but if it
persists, the causes are likely to be similar to
those for FOM state 0.
2 Acquire satellites This means that the instrument is receiving data
from the satellites and is determining which
signals to use.
3 Bad position This means that the instrument detects that
the stored position is different from the current
position. In this case, the instrument will
automatically go to FOM state 4 and reacquire
the position.
TG8000 Multiformat Test Signal Generator User Manual 3–105

Tektronix TG8000 Specifications

General

Brand	Tektronix
Model	TG8000
Category	Portable Generator
Language	English