Abstract: The system for transmission and reception of QAM signals for use in telecommunication networks for any data rates at SNR (signal to noise ratio) of below 0 dB comprises two devices. The first device may be used for transmission Units (1)-(4) transform input bit information sequence (17) with the clock frequency ft (18) into two parallel m-level sequences with the clock frequency ft/2k forming the first and second channels, where k=log2(m). Unit (5) forming additional signals Cos ? ? t ? t 4 ? k , A · Sin ? ? t ? t 4 ? k , where ?t=2?ft. Units (6), (7) multiply m-level sequences of the first and second channels with signal Cos ? ? t ? t 4 ? k for removal phase ambiguity at reception end, and units (8), (9) adding with signal A · Sin ? ? t ? t 4 ? k ? t , defining level of the additional pilot-signal in output spectrum.

Abstract: The system for transmission and reception of QAM signals for use in telecommunication networks for any data rates at SNR (signal to noise ratio) of below 0 dB comprises two devices. The first device may be used for transmission Units (1)-(4) transform input bit information sequence (17) with the clock frequency ft (18) into two parallel m-level sequences with the clock frequency ft/2k forming the first and second channels, where k=log2(m). Unit (5) forming additional signals Cos ? ? t ? t 4 ? k , A · Sin ? ? t ? t 4 ? k , where ?t=2?ft. Units (6), (7) multiply m-level sequences of the first and second channels with signal Cos ? ? t ? t 4 ? k for removal phase ambiguity at reception end, and units (8), (9) adding with signal A · Sin ? ? t ? t 4 ? k ? t , defining level of the additional pilot-signal in output spectrum. Filters (10), (11) forming baseband QAM signal spectrum and units (12)-(16) shift of spectrum at intermediate or carrier frequency.