Waveform design and spectral analysis in direct digital synthesizing of periodic signals
Zhang Er-yang · 2003
In the direct digital synthesis of periodic signals, the frequency resolutions and bands of the synthesized signals are limited by the working frequency and data capacity of the synthesizing system. In this paper, the relationship between the output spectrum of a direct digital signal synthesizing system and the DFT of the corresponding waveform sequence is analyzed. Then three waveform sequences are designed, two of which can improve the frequency resolution of synthesized signals without changing the amplitude envelopes of their spectra based on fixed working frequency and data capacity, and are referable in the direct digital synthesis of some wide-band periodic signals of high frequency resolution. Another sequence can be used to synthesize signals of variable spectrum by certain rules with definite waveform data. 1fig. ,8refs.