FDM Products Overview

2TM radios

The 2TM xx-xxx analog radio equipment is designed for the transmission of 6-12-24-60-120 telephone channels in the 400-900-1500-2300 MHz bands. All  radio terminals available in Simple (1+0), Hot Stand-by (1+1) or special  custom made configuration.

The equipment features automatic changeover (independent for transmitter and receiver side), redundant power supply, service channel unit allowing engineering conversation with corresponding far terminal and service channel splitting for telegraphy or supervisory signals transmission. Baseband combiner version is also available for space/frequency diversity configurations, improving the time availability of radio system.

RF output level is adjustable, in order to optimize the interference problem in complex node. Provision of metering facilities and visual indications (LED's) allows easy check of the units during routine measurements.

The radio terminal is made up of modules, formed by plug-in units to be inserted into 19" standard shelves. All modules can be easily inserted and withdrawn from the shelf front. Connections between modules are realized by U links placed on the front panel.
RF branching filter is designed for maximum installation flexibility and the mechanical configuration of shelves allows all operations to be carried out from the rack front.
Modular construction, compact packaging and reliable operation are obtained by solid-state technology, making the equipment proposed simple to install and to maintain.

MTU12 multiplex

The MTU12 equipment is a 12 channel multiplex using the frequency division multiplexing technique (FDM) for transmission over analogue radio link.

Double modulation is adopted; the voice band is translated into a premodulation band, by a 128 KHz carrier generated inside the individual channels, and it is filtered by an electromechanical filter which allows to improve electrical performances as frequency response and out of band attenuation.
Subsequently each channel is allocated in the final band by a second modulation process using different carriers generated in every channel modem as a function of the physical allocation in the wired rack.
This modulation technique allows having identical and independent channels, without any active device in common circuit and considerable reducing of the spares for maintenance purpose.

The telephone interface card is very flexible, permitting to built-up the most appropriate channels' configuration in order to match user requirements; moreover other channels can be inserted in the same rack for future implementations of the system.
Channel modem with universal telephone termination plug-in allows to interface any common telephone services as 4 wires plus E&M, local battery, central battery with repeated call, automatic central battery subscriber side, automatic central battery exchange side and direct exchange connection.

Two identical equipment, six 19" RU sub-shelf each, may be simply interconnected for obtaining a resultant 24 channels multiplex equipment.