EndRun Sonoma N12, Руководство пользователя

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S o n o m a U s e r M a n u a l 60
C H A P T E R S E V E N
61 S o n o m a U s e r M a n u a l
H T T P S I N T E R F A C E
WNLSF, DN These fields show the GPS week number and day number of week at the end of
which the future leap second will take effect. This could be in the past if a leap
second insertion has recently taken place. Leap second events occur every few
years on either June 30 or December 31.
A0, A1, These fields show the parameters for calculating the small residual offset
WNt, tot between the GPS master clock ensemble and UTC-USNO. This is typically
less than 10 nanoseconds.
Current This is the current value of the GPS-UTC offset, which includes leap seconds
(GPS-UTC) plus the small residual offset explained above. Time and date of most recently
received satellite transmission containing this data is also shown.
Configuration
Clock Calibration Clock calibration is used to advance or retard the clock in order to correct for
GPS Receiver delay and any propagation delay due to GPS antenna cable.
It may also be used to compensate for the inherent time offsets that may exist
with external hardware such as distribution amplifiers, etc. Calibration range is
±500,000 nanoseconds.
Receiver: Oscillator Page
This page shows system oscillator control information such as:
Oscillator Status
Oscillator Type This field shows the system oscillator type that is installed in the Sonoma. It
will be either TCXO (standard), OCXO (option) or Rubidium (option).
DAC
The system oscillator control DAC value indicates the frequency control setting.
The system automatically sets this value to remove frequency errors. Values
may range from 0 to 1,048,575. Values close to the minimum or maximum will
set the DAC fault flag.
Measured This field shows the last measured time offset of the GPS Subsystem relative to
Time Error GPS while locked, in second.
Time Deviation This field shows the time deviation (TDEV) of the offset measurements in
seconds. The tau associated with this measurement is one second, which is the
update interval of the position fixes received from the GPS Receiver.
Oscillator This field shows the regression-computed system oscillator ageing rate per day
Ageing Rate (several-hours delay before the first measurements are displayed).
Control Loop TAU This field shows the system oscillator control loop averaging time constant, in
seconds. It’s value is automatically adjusted to maintain optimum offset and
stability.