Summary Of Specifications; Modulator - Comtech EF Data CDM-Qx Installation And Operation Manual

CDM-Qx/QxL Multi-Channel Satellite Modem with DoubleTalk™ Carrier-in-Carrier®
Introduction
1.5

Summary of Specifications

1.5.1

Modulator

Note: Features not in the initial product release are identified in parentheses.
Modulation See Table A-5
Symbol rate range Up to 10 Msps (lower end is modulation and FEC rate dependant). Refer to Figure A-1.
Data rate range See Table A-5
Operating modes
Transparent, closed network, DoubleTalk™ Carrier-in-Carrier®
FEC
See Table A-5
Transmit filtering Per INTELSAT IESS-308 (0.35) or 0.20 (for use with closer adjacent channel spacing)
Scrambling V.35 or synchronous
Output frequency 50 to 90, 100 - 180 MHz, 100 Hz resolution (70/140 MHz IF)
950 to 1950 MHz, 100 Hz resolution (L-Band)
Stability ± 1 ppm, 0 to 50
Stability ± 0.06 ppm, 0 to 50
Stability ± 0.06 ppm, 0 to 50
External Reference 1, 2, 5, 10, or 20 MHz @ 0 dBm to +20 dBm. Internal reference phase locks to external
reference.
Harmonics Greater than -55 dBc/4 kHz (typically <-60 dBC/4kHz) – measured from 25 to 400 MHz
(70/140MHz IF)
and spurious
Greater than -55 dBc/4 kHz (typically <-60 dBC/4kHz) – measured from 500 to 2500 MHz
(L-Band)
Spurious measured relative to an unmodulated (CW) carrier
Transmit On/Off 55 dB minimum
Ratio
Output phase noise < 0.48
(minimum of 10 dB better overall than the INTELSAT IESS-308/309 requirement)
Output power -5 to -25 dBm, 0.1 dB steps (70/140MHz IF)
-5 to -45 dBm, 0.1 dB steps (L-Band).
Refer to Automatic Uplink Power Control section.
Power accuracy ±1.0 dB over frequency, temperature, and number of modulators installed in the chassis
Output Connector Type BNC Female (70/140MHz IF)
Type N Female (L-Band)
≥ 19 dB (70/140MHz IF)
Output Return Loss
≥ 10 dB (L-Band)
Clocking Options Internal, ±1ppm or 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 do
not need to be identical
External Clock at transmit data rate.
External TX By TTL 'low' signal or external contact closure - hardware function automatically over-rides
processor
Carrier Off
o o
C (32
o
C (32
o
C (32
0
rms double sided, 100 Hz to 1MHz
1–14
o
to 122 F) (standard low-stability internal reference)
o o
to 122 F) (Optional high-stability internal reference)
o o
to 122 F) (standard reference for L-Band)
Revision 7
MN/CDMQx.IOM