MODULATION SYSTEM AND METHOD TO BE USED IN SPREAD SPECTRUM COMMUNICATION SYSTEMS

The invention relates to a modulation system and method to be used in spread spectrum communication system. According to the invention, the modulation system comprises means (604) for generating an orthogonal sequence signal corresponding to a binary orthogonal sequence selected from a multitude of said sequences and which are meant to receive an input signal and to transform the sequential portions of said input signal into some sequences of the multitude of orthogonal sequences, based on a value of said portion of the input signal, the modulation system also comprising some means (614, 616) for generating a "PN" pseudonoise signal corresponding to a predetermined "PN" binary sequence, and also some means (610, 612) for obtaining the orthogonal sequence signal with "PN" signal and obtention of a resulting signal. According to the invention, the modulation method comprises mainly as stages: a) generating an orthogonal sequence signal corresponding to a sequence selected from a multitude of binary orthogonal sequences by receiving an input signal and transforming the sequential portions thereof into orthogonal sequences selected from the multitude of orthogonal sequences on the basis of a value of the portion of said input signal ; b) generating a "PN" pseudonoise signal corresponding to a predetermined "PN" binary sequence and c) combining the orthogonal sequence signal with the "PN" signal for furnishing a resulting signal. Invenţia se referă la un sistem şi la o metodă de modulare, pentru utilizare în sisteme de comunicaţii cu spectru extins. Sistemul de modulare, conform invenţiei, cuprinde mijloace (604) pentru generarea unui semnal de secvenţă ortogonală, ce corespund unei secvenţe binare ortogonale, selectată dintr-o multitudine de astfel de secvenţe, şi care sunt destinate recepţionării unui semnal de intrare şi transformării porţiunilor secvenţiale ale acestui semnal de intrare, în nişte secvenţe din multitudinea de secvenţe ortogonale, pe baza unei valori a respectivei porţiuni a semnalului de intrare, sistemul de modulare cuprinzând şi mijloace (614 şi 616) pentru generarea unui semnal de pseudozgomot "PN", ce corespunde unei secvenţe binare "PN", predeterminată, precum şi mijloace (610 şi 612) pentru obţinerea semnalului de secvenţă ortogonală cu semnalul "PN" şi obţinerea unui semnal rezultant. Metoda de modulare, conform invenţiei, cuprinde în principal ca etape: a) generarea unui semnal de secvenţă ortogonală, corespunzând unei secvenţe selec