Main purpose of developed modem is providing communication in rough conditions of a power transmission line.

Communication system based on Discrete Multi Tone technology, that allows an adaptive modulation scheme for a frequency grid of more than 2000 carriers.

The photo shows a modem with an 600V interface adaptor.

The modem is designed for use in high voltage(over 600V) wired power transmission channels. Modem uses an adaptive modulation scheme for each DMT subcarrier. The subcarrier frequncy step is 366Hz. Modems allow you to organize point-to-point or point-to-multipoint network topologies. The operating frequency range of the system is 100kHz - 1200kHz.

Significant features are: FEC turbo-codes; Adaptive selection of the frequency range used and individual tuning of modulations for subcarriers; Possibility to exclude individual subcarriers from the operational range (interfering or forbidden frequencies are not used by the transmitter); Small step of the DMT frequency grid, that allows to precisely cut out corrupted frequencies.

These advantages allow the most effective use of the communication channel.

The transmitter design based on MAX44211 chip, which provides high linearity and the ability to operate loads from 10 Ohm.

Receiver AGC control ranges up to 93dB and completely covers the actual requirements for gain control of the RX path.

The modems have two independent pairs of TX and RX channels, which allows you to make 100% reservation.

Data rate is adaptively adjustable in the range from 10kbit/s to 1Mbit/s (using bandwidths up to 1MHz). The system has ability to expand bandwidth up to 8 MHz and increase data rate proportionally.

The permissible intersymbol interference(due to the imperfection of the channel) is 400μs (in case of maximum length of the DMT cyclic prefix).