Research on broadband dither technique in signal acquisition

Abstract

AD converter is one of the core components in the signal acquisition system. The quality of the signal acquisition system is mainly determined by its internal analogue-to-digital converter (ADC) characteristics. However, because of the non-linearity of the ADC itself, the dynamic acquisition range of the ADC is greatly affected. Here, the broadband dither technique in the signal acquisition process is studied. Dither signals are added to the input signal to increase the dynamic acquisition range of ADC. Here, the dithering process was first simulated through Simulink and subsequently an FPGA-based broadband dithering module experiment platform was built. The process of signal dithering was implemented. The data were analysed with Simulink and the Spurious Free Dynamic Range (SFDR) of the ADC is obtained. The broadband dither signal can randomise the harmonic distortion phenomenon, verifying that the dithering technique can improve the SFDR of ADC.