45-/112-tone OFDM

45- & 112-tone OFDM are two groups of waveforms of a proprietary full duplex HF communication system. They are used on links with some Russian diplomatic missions, as well as domestic links between transmission centers.

The system doesn't support automatic channel scanning. Instead, each link has a pre-defined set of up to 4 duplex channels, which the master station tries for a few minutes each, in order from the highest to the lowest.

Waveforms

The system transmits on the upper sideband. Each group is associated with a distinct link establishment system (the bursts).

45-tone

• 45 carriers, 33.33 Bd, 62.5 Hz, BPSK
• 45 carriers, 40 Bd, 62.5 Hz, BPSK
• 45 carriers, 40 Bd, 62.5 Hz, QPSK
• 60 carriers, 35.56 Bd, 44.44 Hz, 8PSK

112-tone

• 112 carriers, 22.22 Bd, 25.64 Hz, BPSK
• 112 carriers, 22.22 Bd, 25.64 Hz, QPSK
• 112 carriers, 22.22 Bd, 25.64 Hz, 8PSK