Q-Lite Satellite Modem Installation and Operating Handbook
6-42
RS422
The station clock input is provided via the RS422 differential station clock
pins on the rear-panel Async ESC connector.
Table 6-45 Station Clock Source
6.2.11.2 Station Clock Frequency
The actual station clock input frequency value must be input to the modem. Valid
frequency values will vary depending on whether the station clock is being used for
terrestrial clocking only or whether it is additionally used for carrier and/or BUC/LNB
control. The appropriate frequency input range will be automatically displayed.
Range:
1000kHz to 10000kHz; step size: 1kHz
Description:
This must reflect the actual frequency of the station clock input as the
modem does not automatically measure the frequency. It is used by the
modem in programming the terrestrial interface clocking logic.
Table 6-45 Station Clock Frequency (when not locking the high-stabiliy oscillator)
Options:
10MHz, 5MHz, 2MHz, 1MHz
Description:
This must reflect the actual frequency of the station clock input as the
modem does not automatically measure the frequency. It is used by the
modem in programming the terrestrial interface clocking logic.
Table 6-46 Station Clock Frequency (when locking the high-stabiliy oscillator)
6.2.11.3 Locking the High-Stability Oscillator to the Station Clock
This is an On/Off control that determines whether the modem’s internal high-stability
oscillator is slaved to the station clock input. The high-stability oscillator is used in carrier
and BUC/LNB control. It therefore provides a way of extending system clock
synchronization to ancilliary equipment beyond the satellite modems.
6.2.12 Edit->Unit->SAF Screen
The
Edit->Unit->SAF
screen is shown in
Figure 6-18
. The concept of Software Activated
Features (SAF) is explained in
Section 7-4
.