Tektronix SPG8000 Technical Reference page 173

SPG8000 Technical Reference
GPS lock status: Displays the status of the GPS lock function:
Boot indicates that the function is still in special modes needed to get
started.
Coarse indicates that the function is still tracking significant changes in
the timing.
Fine indicates that the function has stabilized to the point that the loop
only needs to make small changes.
CALIBRATION. Displays the tuning control word for the calibrated frequency
of the mainframe oscillator and how far the instrument is deviating from the
calibrated frequency to achieve a lock to the internal reference.
The first part of the CALIBRATION readout indicates the fractional amount of
deviation from the calibrated frequency. For example, a readout of "0.59e-6"
indicates a fractional correction of 0.59 parts per million. When a calibration of
the instrument oscillator is performed, the CALIBRATION readout values will
typically change. Over the life of the oscillator oven, the expected frequency drift
is ±2.5 e-6, so this number should always be in this range. If the fractional number
is not within this range, then the instrument may have been miscalibrated, or the
oscillator oven may have drifted out of specification since the last calibration. In
this case, you should consider calibrating the internal frequency of the instrument
using the CALIBRATE OVEN menu item in the SYSTEM button menu. (See
page 135.)
PLL STATUS MAIN. Displays the following information about the internal clocks
used to drive the video outputs. Use the left (◄) or right (►) arrow button to view
all of the clock information.
PLL STATUS MAIN: Displays the frequency in MHz and the lock status for
each of the internal clocks used to drive the video outputs. All of the clocks
should show a status of locked (LK) during normal instrument operation.
PLL STATUS SDI: Displays the following information about the clocks used
to generate SDI signals (Option SDI only).
Flex0: Indicates the state of the flexible clock generator for output channel
1 (SDI 1A and SDI 1B connectors). This readout should show Lock
(locked). An Unlk (unlocked) reading might indicate a problem with the
Option SDI board or with the instrument.
Flex1: Indicates the state of the flexible clock generator for output channel
2 (SDI 2A and SDI 2B connectors). This readout should show Lock
(locked). An Unlk (unlocked) reading might indicate a problem with the
Option SDI board or with the instrument.
SYSTEM button menu
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