Filtering by Aliasing: Sharp Programmable Integrated Filters using Simple Time-Varying Components

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

THIS IS AN EXCELLENT PROPOSAL WHICH WILL MAKE SIGNIFICANT CONTRIBUTIONS TO WIRELESS COMMUNICATION RECEIVERS AND WILL ALLOW ENHANCED ACCESS TO THE RADIO SPECTRUM. THIS IS BECOMING VERY CRITICAL SINCE SPECTRUM ACCESS IS BECOMING A MAJOR SOCIETAL ISSUE. THIS RESEARCH, IF SUCCESSFUL, WILL ALLEVIATE SOME OF THESE PROBLEMS AND WILL RESULT IN MAJOR SOCIETAL BENEFITS. IT ALSO CONTAINS A COMPREHENSIVE PLAN FOR OUTREACH ACTIVITIES AND INTEGRATION OF RESEARCH AND EDUCATION. BROADER IMPACTS The broader impacts of the project are at least two fold. First, the research activity brings a breakthrough in the design of reconfigurable integrated filters that is crucial to the re-search on software-defined and cognitive radios and the growth of communication systems in particular and the electronics industry in general. In particular, enabling cognitive radios can po-tentially support the increasing demand for more private and public connectivity in the near fu-ture. Second, the results and discoveries of the research activities will be useful in developing academic material and training future circuits and systems designers in the importance of multi-disciplinary thinking for solving current and future communication systems problems. INTELLECTUAL MERIT The objective of the proposed research is to develop sharp, programmable integrated fil-ters that will enable a wide range of applications including software defined and cognitive radios. Such filters will reduce the bandwidth and the dynamic range of the received communication signals rendering them amenable to digitization and subsequent receiver processing. The proposed approach is to employ simple but periodically time-varying circuit components to significantly enhance effective filtering at sampling instances prior to digitization. The intellectual merit of the research is that the use of periodically time-varying components is a much more efficient and fundamentally different approach to circuit design. Today, most filters are of the time-invariant variety and particularly in the wireless receiver, they need high quality acoustic filter components that are bulky, expensive, difficult to integrate and most importantly, not programmable. The proposed approach will obviate the need for such inflexible components. Specific goals of the proposed research are validation using a prototype integrated circuit and the development of necessary theoretical methods to analyze time-varying circuits. It is expected that the latter will also enable wider acceptance of periodically time varying circuits beyond filter design applications.