Operation M7/M7L/M7LT Modular Satellite Modem1-12 M7/M7L/M7LT - Rev. 0.051.5. M7 Capabilities1.5.1. Inter-Facility Interface (IF)The M7 series is offered with two (2) IF variations designed to meet the needs of various earthstations. IF = 50-180MHz (TX/RX) L-Band = TX = 950-2150MHz, RX = 950-2150MHzThe standard M7 modem is equipped with a 50 to 180 MHz transmit and receive IF. This version istypical for use in traditional earth stations with IF to RF up and down converters between the modemsand the High Power Amplifiers (HPA).The M7L equipped with L-Band transmit and receive IF that provides optional 10MHz FrequencyReferences for the BUC and LNB. This modem is ideal for earth stations that are designed with ablock 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 thelow power outdoor RF equipment. This creates the ability to build extremely simple and low cost highperformance remote terminals.1.5.2. Sharp Carrier TechnologyThe M7 provides multiple setting for the modulation carrier roll-off that will allow interoperability withindustry standards and optionally to increase the number of carriers that can be placed in a satellitetransponder. This capability is referred to as “Sharp Carrier Technology”.There are eight (8) filter roll-off options available to set in the modulator menu Off> and demodulator menu . 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 comparisonof 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
