Comtech EF Data CDM-710, Инструкция по установке и эксплуатации

Страница: 162 / 242

CDM-710 Broadcast Satellite Modem Revision 11
CDI-40 ASI Interface Module MN/CDM710.IOM
8–6
8.4 General Specifications
General Specifications
Data Framing Formats
ASI: 188 or 204 byte packets per ETS 300 421.
Test Pattern Tx only, 2047 or 2
23
-1 pattern compatible with typical BER tester
Hot Pluggable No
ASI Specifications
Data Rate
Up to155 Mbps
Tx Clock Rate Acquisition
Programmed data rate ± 100 ppm
ASI Transport The transport rate is 270 Mbps for all data rates
Impedance
75
Ω
Return Loss 13 dB over 5 to 270 MHz
Connectors BNC Female
Electrical Properties Per EN 500083-9
Packet Types Burst or distributed
Signal Types Serial data
Voltage Level Rx Out
800 mV ± 10% into 75 Ω , (J2, J3 of PL/10881-3 or J2 of PL/10881-4).
J3 of PL/10881-4 is higher for 1:1 applications for 800 mV typical after 3 dB combiner
(Figure 8-3).
ASI Data Loop 3 dB
Frequency, Tx Only
•
Wide – 2 Hz
• Narrow – 0.5 Hz
Jitter Tolerance Meets ITU-T G.823 (3/93) and ITU-T G.824 (3/93)
Jitter Transfer
≤
0.5 dB peaking up to cutoff frequency; -20 dB per decade beyond cutoff.
Cable Length, Typical
•
30 meters (100 feet), RG59
• 40 meters (140 feet), Belden 8281
Tx Input Selection Two inputs, with selection to control which is active
Loss Of Tx Input Data Null packets are formed and transmitted. Loss of Tx Input is selectable as a fault or alarm.
Monitor & Control
Controlled Functions
•
Interface I/O Loopback, Digital Loopback
•
Data Rate
• Loss of Data, Mask as Fault or Alarm
• Variable ASI Mode
Monitored Functions
• Loss of Tx Data – The modulator indicates a loss of sync (framed modes) and
transmits Null Packets in the data portion of the frame.
• Tx Clock PLL Program Error
• Data Violations (Tx)
• FIFO Faults
ASI Input Select Input J4 or Input J5
ASI Data Loop BW Selection Wide and Narrow (Tx Input Data)
PCR Jitter (RX Output)
• Less than 100ns after settling
• Settling to < 500ns, 20 seconds
•
Peak PCR jitter < 1000ns typical during settling