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Compatibility, Description of the modulator, Overview – Comtech EF Data SNM-1001L User Manual

Page 29: Functional description, 5 compatibility, 6 description of the modulator 1.6.1 overview, 2 functional description

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SNM-1001L Satellite Modem

Revision 1

Introduction

MN/SNM1001L.IOM

1–5

1.5 Compatibility

The SNM-1001L is functionally compatible with many Comtech EF Data modems.
When properly configured, the unit will interoperate with the following Comtech EF
Data modems:

• CDM-550/550T (Turbo only)

• SDM-650B

• CDM-600 (Open Network and Turbo only)

• SDM-6000

• SDM-100/100A

• SDM-8000

• SDM-300/300A

• SDM-150A

• SNM-1010

1.6

Description of the Modulator

1.6.1 Overview

The modulator provides PSK modulated carriers within the 950 to 1750 MHz range. The
types of modulation that encode the transmitted baseband data from the interface PCB
are:

• BPSK
• QPSK
• Offset QPSK
• 8-PSK

1.6.2 Functional

Description

The modulator is composed of eight basic subsections. These subsections are divided into
the baseband processing section and the RF section of the modulator. The modulator
controls all programmable functions on this module. Fault information from the
modulator is sent to the M&C. Refer to Chapter 9 for a list of reported faults. The major
modulator subsections are:

• Scrambler/Differential Encoder
• Convolutional Encoder
• Programmable Vector Rotation
• I/Q Nyquist Filters
• Modulator
• RF Synthesizer
• Output Amplifier
• Output Level Control