FIELD: mobile code-division multiple access communication systems. SUBSTANCE: device has pseudonoise (PN) code sequence generator for shaping PNi and PNq sequences; orthogonal code generator affording change of differential phase keying phase with intervals of at least two code items; and generator shaping extending codes Ci and Cq by mixing up (221, 223, 224) Ci and Cq code sequences with first and second orthogonal codes so that current phase of extending codes PNi and PNq changes in turn state of quadrature phase keying and differential phase keying with respect to preceding phase of extending codes Ci and Cq. EFFECT: reduced maximal-to- medium power ratio without impairing bit error rate characteristic. 27 cl, 22 dwg
