Comtec CDM-840 - Modulator; Transmit

CDM-840 Remote Router MN-CDM840
Introduction Revision 3
1–11
1.4.3 Modulator
Parameter
Specifications
Operating Frequency
950 to 2150 MHz L-Band, 100 Hz frequency resolution
Frequency Reference
±0.06 ppm (±6 x 10-8), 0 to 50°C (32 to 122°F)
Scrambling
Comtech, disabled
Spectral Inversion
Normal or Inverted
Transmit Filtering
Per IESS-308/-309 spectral mask
Transmit Filter Rolloff (Alpha)
20%, 25%, 35%
Output Power
0 to -40 dBm, in 0.1 dB steps
Power Accuracy
±1.0 dB over frequency, data rate, modulation type and temperature range of 0 to 50°C
Transmit On/Off Ratio
-60 dBc minimum
Harmonics and Spurious
Better than -60 dBc/4 kHz (typically < -65 dBc/4KHz)
Measured from Fo ±300 MHz
Output Phase Noise
<1º rms double sided, 100 Hz to 1MHz (minimum of 6 dB better overall than the Intelsat
IESS-308/309 requirement)
dB/Hz
Frequency
-66.0
-76.0
-86.0
-96.0
100 Hz
1 kHz
10 kHz
100 kHz
Fundamental AC line spurious is -42 dBc or lower. The sum of all other single sideband
spurious, from 0 to 0.75 x symbol rate, is -48 dBc or lower
Connector / Impedance
Type ‘N’ female, 50Ω
Return Loss
20 dB, minimum
External Tx Carrier Off
By TTL ‘low’ signal
Test Modes
CW, 1/0 pattern, 2^23-1 and 2047 patterns
1.4.3.1 Transmit
Return (Remote to Hub) Parameter
Specifications
Transmit Power
0 to -40 dBm
Data Rate
16 kbps to 15.35 Mbps, in 1 bps step (CCM mode) (Modulation and FEC dependent)
Symbol Rate
16 ksps – 4.5 Msps
FEC Mode
VersaFEC Encoder (ACM and CCM modes)
Modulation and Code Rates
• BPSK 0.488 (16.00 kbps – 2.19 Mbps)
• QPSK 0.533 (17.07 kbps – 4.80 Mbps)
• QPSK 0.631 (20.19 kbps – 5.67 Mbps)
• QPSK 0.706 (22.577 kbps – 6.34 Mbps)
• QPSK 0.803 (25.69 kbps – 7.22 Mbps)
• 8-QAM 0.642 (30.83 kbps – 8.67 Mbps)
• 8-QAM 0.711 (34.14 kbps – 9.60 Mbps)
• 8-QAM 0.780 (37.44 kbps – 10.53 Mbps)
• 16-QAM 0.731 (46.80 kbps – 13.26 Mbps)
• 16-QAM 0.780 (49.92 kbps – 14.04 Mbps)
• 16-QAM 0.829 (53.04 kbps – 14.91 Mbps)
•
16-QAM 0.853 (54.60 kbps – 15.35 Mbps)
Encapsulation
Ultra-low overhead Streamline Encapsulation