Operation
M7/M7L/M7LT Modular Satellite Modem
1-12
M7/M7L/M7LT - Rev. 0.05
1.5.
M7 Capabilities
1.5.1.
Inter-Facility Interface (IF)
The M7 series is offered with two (2) IF variations designed to meet the needs of various earth
stations.
IF = 50-180MHz (TX/RX)
L-Band = TX = 950-2150MHz, RX = 950-2150MHz
The standard M7 modem is equipped with a 50 to 180 MHz transmit and receive IF. This version is
typical for use in traditional earth stations with IF to RF up and down converters between the modems
and the High Power Amplifiers (HPA).
The M7L equipped with L-Band transmit and receive IF that provides optional 10MHz Frequency
References for the BUC and LNB. This modem is ideal for earth stations that are designed with a
block Up and Down conversion making it ideal for low cost earth stations.
The M7LT is an extension of the M7L that provides the LNB and BUC power supplies to power the
low power outdoor RF equipment. This creates the ability to build extremely simple and low cost high
performance remote terminals.
1.5.2.
Sharp Carrier Technology
The M7 provides multiple setting for the modulation carrier roll-off that will allow interoperability with
industry standards and optionally to increase the number of carriers that can be placed in a satellite
transponder. Thi
s capability is referred to as “Sharp Carrier Technology”.
There are eight (8) filter roll-off options available to set in the modulator menu
<Mod: IF - Filter Roll-
Off>
and demodulator menu
<Demod: IF - Filter Roll-Off>
. These optional filter “Alpha” values
“0.40”, “0.35”, “0.30”, “0.25”, “0.20”, “0.15”, “0.10”, 0.08” and “0.05”. Figure 1-9 shows an comparison
of two (2) spectrum plots one which is 0.35 Alpha (red) and the other 0.08 Alpha (green).
Figure 1-9
– Spectrum Analyzer Plot of 0.35 verses 0.08 Roll-off factors
