Studies of improving the performance of A/D conversion by post band-pass filtering method

In digital signal processing, it is crucial to improve the precision of A/D conversion (ADC) on the condition that the bandwidth of signals and sampling frequency are preset. Over the past years, the study about reducing quantization noise resulted from ADC by means of post band-pass filtering, aiming at band-pass signals in communication, is relatively rare. This paper suggests a method to reduce quantization noise of bandpass signals and improve the precision of ADC by adding a post digital band-pass filter. The effectiveness of the proposed method is then proved through numerical simulations by taking the common intermediate frequency (IF) band-pass signal as an example; the results show that, after the post bandpass filtering, the quantization noise is significantly reduced, which implies the improvement of precision of ADC. In addition, in the theoretic aspect, this paper revises some traditional views of quantization noise´s statistic model and relaxes the assumption which considers the quantization noise as a white one.