FIELD: variable-speed data transmission. SUBSTANCE: transmitter incorporating in-phase circuit and quadrature circuit for transmitting composite signal with extended spectrum for at least two physical channels has facility coupled with mentioned in-phase circuit for data extension using first extension code from code tree and facility coupled with mentioned quadrature circuit for data extension using second extension code chosen from code tree; first and second extension codes have different number of elements and are chosen from code tree so as to ensure that first and second extended physical channels generated by them are relatively orthogonal. EFFECT: provision for equalizing power between transmitter circuits. 22 cl, 4 dwg
