Comtech-ef-data SDM-2020 Instrukcja Użytkownika Pobierz pdf (Strona 167)

11–1

Chapter 11. G.703 Interface

This section describes the plug-in G.703 Data Interface used with the SDM-2020

Demodulator.

11.1 G.703 Data Interface (PL/6168-1)

The G.703 interface provides connection to the standard plesiochronous digital hierarchy

(PDH). With this interface the modulator or demodulator operates at a fixed rate of 6.312,

8.448, 32.064, 34.368, 44.736, or 51.840 Mbps. An auxiliary connector provides open

collector fault lines for reporting a failure to external equipment like a redundancy

switch. The G.703 signals connect to the module’s BNC female connectors, and the

signals supported are SD, RD and EXT (external) Clock.

This data interface also contains a receive buffer that provides 0 (bypass) to 32 ms in 2

ms steps. The input clock to the receive buffer is always from the satellite, but the output

of the buffer is selected from the satellite clock, EXT Clock or a clock derived from SD.

A separate auxiliary connector provides modulator and demodulator fault status for

connection to a redundancy switch or other equipment.

IMPORTANT

This module is used in either the SDM-2020 Modulator or Demodulator.

11.1.1 Applicable Documents

Applicable documents, as referenced herein, include:

• ITU-T G.703, Physical/Electrical Characteristics Of Hierarchical Digital

Interfaces

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