Comtech EF Data DMDVR20 LBST Rev 1.1 User Manual
Page 43
User Interfaces
DMDVR20 LBST Satellite Modem
4-6
TM136 – Rev. 1.1
CARR DLY(SEC)
{0-255}
Allows the user to select the time delay after power-up
before the Tx Carrier may be enabled. This allows time
for the BUC to stabilize.
SPECTRUM {NORMAL, INVERTED}
Allows the user to invert the direction of rotation for
QPSK Modulation. Normal meets the IESS
Specification.
Spectral inversion may be required if the BUC LO is
higher in frequency than the BUC output frequency.
When BUC LO is higher than the BUC output frequency,
this creates a spectral inversion and the IF Spectrum
must be again inverted to compensate.
MODULATION {QPSK,
BPSK, OQPSK, 8PSK, 16QAM}
Allows the user to select the modulation type.
SPECTRAL MASK
{Intelsat 0.35, DSS SAT 0.35, DSS SAT 0.25, DSS
SAT 0.20}
Allows the user to set the spectral shape of Tx Data
Filter.
COMPENSATION
{0.0 – 1.0}
Allows you to offset output power by up to 1 dBm. This
is intended as a correction for user cabinet connectors.
DATA (menu)
DATA RATE (bps)
{Refer to Technical Specs for Data Rates}
Allows the user to set the Data Rate in bps steps via the
Front Panel Arrows or Keypad.
SYMB RATE (sps)
Allows the user to view the Symbol Rate.
INNER FEC
Viterbi
{1/2, 3/4, 7/8, None}
Optional FEC Rates:
Sequential
{1/2, 3/4, 7/8}
Trellis
8PSK
{2/3}
Turbo
{1/2,
3/4,
7/8}
Comstream
Seq {3/4}
Allows the user to select the Tx Code Rate and Type
DIFF CODING
{ENABLED, DISABLE}
Allows the user to enable or disable the Differential
Encoder. Having the encoder enabled ensures proper
phase lock. May not be adjustable in some modes.
SCRAMBLER SEL
{NONE, V.35-IESS, V.35 CITT, V.35 EF, IBS
w/Optional Framing and optional Reed-Solomon,
Reed-Solomon Scrambler w/Optional Framing,
CCITT, V.35FC, V.35EF_RS, TPC SCRAMBLER
(Turbo Codec)}
Allows the user to select the descrambler type.