Effect Analysis of the Broadband Dithering Signal Amplitude on Acquisition Performance of A/D converters

In the application field of A/D converters(ADCs), dithering technique is a common method to improve the performance of ADC data acquisition. However, the effect of the dithering signal amplitude is still unclear. To solve this problem, a simulation and experiment strategy is developed and applied in this paper. In the plan approach, a dithering signal with variable bandwidth amplitude is designed firstly. Then, according to a planed schedule, the signal is introduced to a normal ADC system. Finally, effect of the dithering signal amplitude is reflected via the resulting variation law of Spurious-noise Free Dynamic Range (SFDR). Simulink simulation based on MATLAB is carried out with adjusting the amplitude of the PN sequence dithering signal. Semi-physical simulation based on Visual Studio and a data acquisition card is executed by setting the amplitude of dithering signal. The mapping analysis shows that the SFDR parameter value and the dithering signal amplitude are in accordance with positive skewness. This work provides reference information about the dithering signal amplitude and will facilitate the ADC design process somewhat.