Method to Obtain Sharp Programmable Filters Using Simple Passive Switched-Resistor Circuits

Researchers at UCLA have designed a method to significantly enhance the selectivity of an analog filter.

Electronic filters are analog circuits which perform signal processing functions, specifically to remove unwanted frequency components from the signal, to enhance wanted ones, or both. Active filtering solutions typically employed at baseband stages exhibit high hardware costs to settle the tradeoff between selectivity and reconfigurability. Furthermore, state-of-the-art passive filtering solutions typically employed at radio frequencies can achieve some reconfigurability and good linearity but exhibit very weak selectivity.

UCLA researchers from the Department of Electrical Engineering have developed a method for producing a low-cost communications receiver that can simultaneously provide reconfigurability and highly selective filtering for both radio frequency (low-pass) and baseband (band-pass) applications. The invention modulates the impulse response of the filter to both program it and enhance its performance.

The technique has been analyzed mathematically and verified using computer simulations. The invention is currently at the prototype development stage where an integrated circuit is under design and fabrication.