FIELD: digital data transmission. SUBSTANCE: method that can be used to implement multichannel modems with multiple-frequency parallel orthogonal composite signals involves shaping of N-channel relatively orthogonal harmonic signals, their relative phase modulation, filtering of multimode signal, and radiation of the latter to receiving device; each of relatively orthogonal N-channel harmonic signals is sampled to shape N parallel trains of count pulses, N parallel trains of count pulses of relatively orthogonal harmonic channel signals are transformed by sequential switching into single multimode train of count pulses, multimode train count pulses are amplified and applied to filter input; in using one- or two-fold relative phase modulation of relatively orthogonal harmonic channel signals count pulses are shaped when sampling relatively orthogonal N-channel harmonic signals in which instant values of harmonic channel signals equal 
of their amplitude U0. EFFECT: reduced requirement to dynamic range of multimode signal gain and improved energy efficiency of its transmission. 2 cl, 1 dwg
