The function of this Unit is to convert the IF sub-bands of a satellite signal to a common 70MHz/80MHz frequency and make the converted signal available for further processing. Developed to comply with
very strict technical and operational requirements, the IF Converter incorporates advanced design and new-generation technologies in the areas of signal processing (frequency synthesis, mixing and filtering.) and microprocessor control. The Unit is
configured in a 3U 19” standard rack, the circuits are assembled into plug-in modules which can be plugged out for inspection , troubleshooting or replacement without switching the equipment off.
The modules complement includes:
IF Interface Module, this module provides input/output separation, adjustments
on the input signal level through combined attenuations / amplifications, and splitting of the signal into three outputs which are fed to three mixer modules.
Mixer Module, each mixer module extracts the 25 kHz channels from the IF
channel available at the output of the IF Interface Module, which are applied to the mixer circuits for frequency conversion to a 70MHz IF, filtered by high-selectivity filters and made available at the module output.
Synthesizer Module, this module contains three high spectral purity,
programmable PLL synthesizers which generate the injection frequencies used in the mixing processes for channel extraction and frequency conversion.
Operation of the synthesizer module is programmed by the CPU internal to the Unit
through keyboard and display
Microprocessor Module located on the Unit front panel, this module contains:
a CPU card
a keyboard card
a display card
over shielded flat cables.
The module is also provided with interface circuits for CBIT and IBIT.
Power Supply Module, it includes two identical power supply circuits in a
redundant configuration, each with a rated power which exceeds by 50% the nominal power consumption of the Unit. Front panel leds indicate the presence of malfunctions.
A summary of the technical characteristics of the IF Interface Unit developed for an international satellite communications programs is given below:
Input IF central frequencies 62.5507 68.500/77.450MHz
IF conversion frequencies 70MHz for 1 to 4 channels
80MHz for 5 channels
70MHz IF filter bandwidth 23kHz @3dB
80MHz IF filter bandwidth 200kHz @ 1dB
Filter’s group delay 30µ sec
L.O. rejection ≥70dB
Ro.Ma. Enginery - Via Costarica n.6 - 00040 Pomezia Roma -
ITALIA - Tel.: +39069112483-+390691604670 Fax: +390691141867 e-mail: