Comtech EF Data SDM-300A - Manual (Page 365)

SDM-300A Satellite Modem Revision 6
Specifications MN/SDM300A.IOM
19–9
19.4.7 Transmit Frequency (IF)
The range of the output IF spectrum is selected by the operator from 50 to 180 MHz, in 1 Hz
steps.
19.4.8 Frequency Reference
SCT, RX Bit Clock, and IF output are locked to the Frequency Reference.
Frequency Reference Remarks
Internal (Standard Stability over the operating temperature range = ± 10 PPM.
Internal High Stability
(Optional) Stability over the operating temperature range = ± 0.2 PPM.
External Reference Input
(Standard) The External frequency reference connector is located on the back panel. This allows
Frequency Reference to be locked to an external reference frequency standard.
Impedance 75
Ω
Frequency 1, 5, 10 or 20 MHz
Amplitude
≥ +0 dBm < +20 dBm
DC offset Capacitively coupled
Connector BNC
Reference Frequency
Output (Optional) The External frequency reference connector can be used as an output when the
High Stability option is installed. When selected from the front panel, this output
can be used to lock other equipment to the Internal High Stability Reference of
the selected modem. The output is 10 MHz, the level is +10 dBm
± 5 dBm.
19.4.9 Transmit Frequency Change Time
The time between the end of a remote command and the end of the modem reply for
frequency change and synthesizer lock is < 500 mS.
19.4.10 Phase Noise
The phase noise of the TX-IF output carrier is no worse than:
dBc/Hz Distance from Carrier
-66.0 100 Hz
-76.0 1 kHz
-86.0 10 kHz
-96.0 100 kHz
-96.0 1 MHz
Fundamental AC line spurious is –42 dBc or lower.
The sum of all the single sideband spurious, from 0 to 0.75 x symbol rate, is –42 dBc or
lower.