Operating instructions

User Interfaces DMD20/DMD20 LBST Universal Satellite Modem
4-16 TM103 – Rev. 2.8
IF (menu)
FREQUENCY (MHz) {50 – 90 MHz, 100 – 180 MHz, or 950 - 2050 MHz}
{950 – 2050 MHz} for LBST}
Allows the user to enter the Modulator IF Frequency in 1
Hz increments.
DWNLNK FREQ (MHz) Displays the input frequency into the LNB from the
satellite, also referred known as Satellite downlink
frequency. The user must enter the LNB LO and OSC
SIDEBAND of the LNB before using this menu. The
DOWNLINK FREQUENCY is a calculated measurement
of both the LNB LO and OSC SIDE BAND. Once the
menus are entered correctly, the user can control the
downlink Frequency from this menu.
SPECTRUM {NORMAL INVERTED}
Allows the user to invert the direction of rotation for PSK
Modulation. Normal meets the IESS Specification.
LBST: Spectral inversion may be required if the LNB LO
is higher in frequency than the LNB input frequency from
the satellite. When LNB LO is higher in frequency than
the LNB input frequency, this creates a spectral
inversion and the IF Spectrum must be inverted to
compensate for the inversion.
MODULATION {QPSK, BPSK, OQPSK, 8PSK, 16QAM}
Allows the user to select the demodulation type.
SPECTRAL MASK {Intelsat 0.35, DVB 0.35, DVB 0.25, DVB 0.20}
Allows the user to set the spectral shape of Tx Data
Filter.
SWEEP RANGE (kHz) {±0 to 255 kHz}
Allows the user to set the acquisition range for the
demodulator
SWEEP DELAY (Sec) {0.0 – 6553.5 sec}
Allows the user to set the reacquisition delay time in
1/10
th
second increments.
REACQ RANGE (Hz) {0 – 65535 Hz}
Allows the user to set the reacquisition sweep in 1 Hz
increments.
ADJ CARRIER PWR {Normal, Suppressed}
Allows the user to indicate adjacent carrier as Normal or
Suppressed (High Power). Unit will increase or decrease
post decimination gain appropriately.
FAST ACQUISITION {DISABLED, ENABLED}
Allows the user to disable or enable the Rx fast
acquisition capability.