4 modem specifications – Comtech EF Data SDM-100A User Manual

Page 21

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SDM-100A Satellite Modem

Introduction

Rev. 0

1–5

1.4 Modem Specifications

Table 1-1 lists the operating specifications of the modem.

Table 1-1. SDM-100A Specifications

Modem Specifications

Operating Frequency Range

50 to 180 MHz, synthesized in 2.5 kHz steps.

Type of Modulation

Quadrature Phase Shift Keying (QPSK), or
Bi-Phase Shift Keying (BPSK).

Operating Channel Spacing

Less than 0.5 dB degradation operating with 2
adjacent-like channels, each 10 dB higher at 1.3
times the symbol rate, or a minimum of 1.2 times the
specified acquisition range.

Bit Error Rate

See Table 1-2.

Phase Noise

In accordance with IESS-308.

Digital Interface

RS-422/449 on 37-pin D.

(Field Changeable Plug-in modules)

MIL-STD-188 on 37-pin D.

(One interface per module.)

V.35 on 25-pin DIN.

RS-232-C on 25-pin D.

Asynchronous.

ADPCM.

Digital Data Rate

BPSK, 1/2 Rate

9.6 to 64 kbit/s.

QPSK, 1/2 Rate

19.2 to 128 kbit/s.

QPSK, 3/4 Rate

28.8 to 192 kbit/s.

QPSK, 7/8 Rate

33.6 to 224 kbit/s.

Doppler Buffer

Programmable from 64 to 65536 bits, or from 1 to
50 ms total depth.

Buffer Output Clock

Transmit, Receive, Internal, or External.
Transmit and external clocks must be to data rate.

Forward Error Correction

Convolutional Encoding with Soft Decision.
K=7 Viterbi Decoding, or Sequential.

Data Scrambling

Selectable (International Telephone and Telegraph
Consultative Committee) CCITT V.35, or None.

Prime Power

90 to 264 VAC Auto Select, 47 to 63 Hz,
50W Max., Fused at 2A. (48 VDC optional.)

Size

1.75” H x 19.0” W x 20.0” D. Refer to Figure 1-3.

Operating Temperature

0

°

to 50

°

C.

Storage Temperature

-20

°

to +70

°

C.

Humidity

0 to 95

%

noncondensing.

Diagnostic Features

IF Loopback.

RF

Loopback.

Baseband Loopback (Bi-directional, electrical).

Fault

Monitoring.

Bit Error Rate Monitoring.

Remote Control via Serial Port.

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