The quantization noise of phase and amplitude in digital signal synthesizers and methods of their decreasing. The methods of discrete approximation of linear law modulation by using method of direct digital synthesis are considered. The analysis of component noise in forming by method of direct digital synthesis because of phase jitter of synchrosignal, truncation of phase code, finite DAC width is brought. It is displayed that in modern devices of direct digital noise synthesis of synthesized signal are determined mainly by DAC width. Calculated data of noises dependency from phase and amplitude quantization in sin signal and also with linear frequency modulation in discrete approximation with law of frequency variation are brought.
method of direct digital synthesis, DDS, power spectrum density, phases noises