Sampling Technology of Wide-Band Signals Based on Modulated Hybrid Filter Banks

It is difficult to use a single analog-to-digital conversion (ADC) to satisfy the requirements for conversion of an ultra-wideband signal. A parallel architecture for wideband ADC, named cosine modulated hybrid filter bank, is presented to address this problem. First, the proposed architecture shifts the input signal spectrum by means of mixers. The modulated signal is channelized into smaller frequency subband signals using identical lowpass analog filters. Then the subband signals are digitized through identical narrowband ADCs, respectively. Finally, the digitized signals are up-sampled, filtered and combined to reconstruct the digital representation of original wide-band input signal. The digital filters are designed to the eigenfilter method based on total least squares error criterion. Since the sample-and-hold circuits needed in this architecture are simple identical narrowband baseband circuits, which makes the design easier and cheaper. Several design examples are presented to illustrate the performance of the proposed system.