Radyne DMDVB20 LBST, Installation And Operation Manual

Page: 46 / 113

User Interfaces DMDVB20 LBST Satellite Modem
4-10 TM138 – Rev. 1.0
4.3.3 Demodulator Menu Options and Parameters
NETWORK SPEC The Network Spec Command sets a number of
parameters within the modem to meet a specification.
The purpose is to eliminate keystrokes and potential
compatibility problems.
Data rates not covered by a given mode will not be
allowed. If the mode of operation is selected after the
data rate has been entered, then the data rate must be
compatible with the desired mode of operation or the
Network Spec will not be allowed. The following
parameters cannot be changed while the unit is in the
given mode of operation:
DVB-S2-CCM: Per EN 302 307
Data Rates: All Rates
Framing Type: DVB-S2
Scrambler Type: DVB-S2
Spectrum Mask: DVB 0.20, 0.25, 0.35
IF (menu)
FREQUENCY (MHz) {950 – 2150 MHz}
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, AUTO}
Allows the user to invert the direction of rotation for PSK
Modulation. Normal meets the IESS Specification.
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, 8PSK, 16APSK}
Allows the user to select the demodulation type.
SPECTRAL MASK {DVB 0.35, DVB 0.25, DVB 0.20}
Allows the user to set the spectral shape of Rx Data
Filter.