Modulator Phase Error; Transmit If Test Modes; Encoding; Bpsk Encoding - Comtech EF Data SDM-300A Installation And Operation Manual

Specifications
C.2.16

Modulator Phase Error

The modulator will have less than 2° of phase error
C.2.17

Transmit IF Test Modes

The operator can select the following TX IF test modes. Spurious emissions in the
following test modes will be ≤ -30 dBc.
CW
Offset
Dual sideband
C.2.18 Modulator Spectrum Rotation
The operator can select Normal or Inverted spectrum of the of the Modulator Output.
C.2.19

Encoding

C.2.19.1

BPSK Encoding

The modulator converts transmitted baseband data into a modified BPSK carrier
2.4 kbit/s to 1.25 Mbit/s (1/2 rate) . Using vector analysis of the constellation pattern,
BPSK represents one symbol with the carrier phase either at 0° or 180°. The 1/2 rate
encoding at the convolutional encoder two symbols output for every bit input.
C.2.19.2

QPSK Encoding

The modulator converts transmitted baseband data into a modulated QPSK carrier at the
following parameters:
C–10
Outputs a single carrier at the defined frequency
Dual sideband signal with lower sideband and carrier
suppressed ≤ -35 dBc (≤ -30 dBc for 8PSK only)
Suppressed carrier ≤ -35 dBc (≤ -30 dBc for 8PSK only)
Code Rate
1/2
4.8 kbit/s to 2.5 Mbit/s
7.2 kbit/s to 3.75 Mbit/s
8.4 kbit/s to 4.375 Mbit/s
Symbols/Bit Bits/Hz
2 0.5
1/2 rate
3/4 rate
7/8 rate
SDM-300A Satellite Modem
Rev. 4