Comtech EF Data CDM-625 Installation And Operation Manual page 37

CDM-625 Advanced Satellite Modem
Introduction
Clocking options
External TX
Carrier Off
BUC Reference
(10 MHz):
Phase Noise
BUC Supply Voltage
BUC Current Monitor
Tx Carrier ON Delay
BUC Monitoring
0.0 0.1 0.2
0
-5
Comtech EF Data
CDM-625 Transmit
Power Spectral
-10
Density, referred to
symbol rate
-15
-20
-25
-30
-35
-40
-45
-50
Spectral
density, dB
-55
Internal, ±0.06 ppm (SCT)
External, locking over a ±100 ppm range (TT)
Loop timing (Rx satellite clock) - supports asymmetric operation - Rx and Tx data rates need not be identical
External Clock
G.703 Clock Extension mode – internal ST clock can be slaved to an external T1 or E1 G.703 signal, and a
G.703 timing signal re-constituted at the distant end of the link, regardless of the actual link data rate
By TTL 'low' signal or external contact closure - hardware function automatically over-rides processor
On center conductor of L-Band output connector; 10.0 MHz ± 0.06 ppm (internal reference selected)
0.0 dBm, ± 3 dB; programmable ON/OFF
Source: either Internal Modem Reference or External Reference (10 MHz)
dB/Hz Frequency Offset
-105 10 Hz
-125 100 Hz
-138 1 kHz
-148 10 kHz
-150 100 kHz
Standard unit has no BUC supply.
Optional BUC Supply
•
24VDC, 4.17 Amps maximum, 100W
•
48VDC, 3.125 Amps maximum, 150W @ 50
•
Supplied through Tx IF center conductor and selectable ON/OFF via M&C control.
Min/Max programmable current alarm thresholds.
Selectable feature power on to allow internal ovenized reference to stabilize before turning on Tx carrier.
Intelligent algorithm minimizes delay time based on internal temperature at power-up.
Power level, temperature, power class, PLL lock.
Uses ND Satcom/Global VSAT Forum specification for FSK control and monitoring.
0.3 0.4 0.5 0.6
Intelsat
IESS
308/309
Limit
MN-0000036 (Ref MN/CDM625.IOM)
o
C (180 watts @ 30
0.7 0.8 0.9 1.0
CDM-625
Modulator
typically < -50 dB, and
guaranteed to be
< -45 dB at offsets
> 0.75 Rs
1–11
o
C)
1.1 1.2 1.3 1.4
Symbol Rate, Rs
Intelsat
IESS
308/309
Limit
Revision 1
1.5