V.N. Melchakov - Head of Laboretory, MIREA D.R. Barsky - Ph.D. (Eng.), VNIITSEVT E.V. Egorova - Ph.D. (Eng.), VNIITSEVT A.S. Avetisov - Post-graduate Student, MIREA A.I. Pikul - Deputy General Director, TSNIRTI named after Akademik A.I. Berg S.V. Tsapenko - Post-graduate Student, MIREA B.E. Borec - Post-graduate Student, MIREA

Unilateral modulation changes the position of one of the edges of pulses ( front or rear ), with two-way are moved in different directions leading and trailing edges , but in both cases the pulse duration is determined by the modulating signal u (t), which is a big advantage of the pulse-width modulation as it allows producers dit - signaling without distortion in digital form . In this paper we consider only one-sided modulation of . Thus , the analysis of spectra signals PWM determines that the modulated pulse edge can be both front and back - with the amplitude spectrum will be the same.