Util) Ref (Reference) - Comtech EF Data CDM-570L Installation And Operation Manual

CDM-570L Satellite Modem with IP Module

6.18.3 (UTIL) REF (Reference)

(UTIL, REF) ADJUST
If Adjust is selected, the following sub-menu is displayed:
Fine adjustment of the Internal 10 MHz reference oscillator is possible through this
menu. Use the ▲ ▼ arrow keys to edit the value. Note that in order to facilitate
adjustment, the value is updated as the digits are incremented – the user does not need to
press the ENTER key. The range of values is from –999 to +999.
Note: The numbers displayed here do not correspond to an exact frequency increment. A
(UTIL, REF) WARM-UP DELAY
If Warm-up delay is selected, the following sub-menu is displayed:
Select Disable or Enable using the ◄ ► arrow keys, then press ENTER.
If the user selects Disable, the CDM-570L will power-up and go into normal operational
service without any delay. Because the CDM-570L uses a high-stability oven-controlled
10 MHz reference oscillator (OCXO) there is a finite time required for the oven to reach
operating temperature. Consequently, there will be a frequency error (as great as 2 x 10
when the modem first powers up, and it may take up to 2 minutes before the frequency
has settled to its correct value. This will affect the Tx synthesizer (and hence the Tx
output frequency) the Rx synthesizers, and the generation of the Internal Tx baseband
Internal Freq Ref:Adjust
Warm-up delay (◄ ►,ENTER)
Select Adjust or Warm-up delay using the ◄ ► arrow keys, then press
ENTER.
Internal 10 MHz Freq Ref
Fine Adjust:+017(◄ ►,▲ ▼)
user should perform this fine adjustment while using an external
frequency counter, connected to either:
a) the internal 10 MHz reference, if the user has internal access to the
equipment, or
b) the Tx Output, set for CW, 0 dBm output level, and an exact center
frequency (1000 MHz, for example).
Warm-up delay:
Enable
Disable
(◄ ►,ENTER)
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