From Murmann Mixed-Signal Group

BSEE, Iowa State University, 2008
MSEE, Iowa State University, 2009
Admitted to Ph.D. Candidacy: 2009-2010

Research: Wide-Band Continuous-Time Low-Pass Filter with Linearity Feedback Correction for OFDM Systems

The next-generation wireless communications systems are targeting the 60GHz band to meet the data rate requirements for a wire-free world. Driven by stringent requirements on blocker rejection, these systems call for highly linear integrated active filters with bandwidths on the order of 1GHz which have yet to be reported in literature. Most proposed 60GHz band specifications rely on orthogonal frequency-division multiplexing (OFDM). OFDM systems use pilot tones for channel estimation and calibration purposes. These pilot tones also contain information about the signal path nonlinearity that can be used in a feedback path to correct the filter nonlinearities. It is anticipated that, with this feedback correction, filters with the stringent required specifications for 60GHz band applications will be realizable in modern CMOS processes.

We are currently researching the bounds on linearity correction for ultra-wideband Gm-C filters as well as refining a robost nonlinearity correction algorithm for filters in OFDM systems. A test chip is being designed that will serve as a vehicle to test the correction algorithm and bounds on circuit level wideband nonlinearity cancellation.

Email: rboesch AT stanford DOT edu