Adaptive Signal Identification using LMS Filter with an Analog Memory Cell

This paper presents the performance of optimal filtering; LMS with a nonvolatile analog memory cell fabricated through 1.2um CMOS process, for the adaptive identification signal problem, where transfer functions are unknown and changing. The memory stores the weight in the filter as charge on the floating gate of a transistor pMOS. The update is linear, using a pulse density modulation scheme by means of tunneling and injection mechanisms. The LMS algorithm is implemented digitally off chip, and it does not require the signal to be piecewise stationary, and requires no manual operation other than selection of the step-size.