Adaptive IIR bandpass decimation filter for single sinusoid detection

This paper proposes an adaptive second-order IIR bandpass decimation filter for detecting a single sinusoid with an unknown frequency embedded in nois e. The purpose is to realize a filter with high Q (selectivity) and less ou tput amplitude fluctuation after convergence. As the first step, the adapti ve second-order IIR bandpass filter with the variable center frequency is o utlined. Then, we present a new method that derives the decimation filter f unction with a small amount of computation. The filter is derived from the above filter with the denominator coefficient made variable, and with the p olynomial of z(-M) as the denominator, where M (integer) is the decimation ratio. A method is shown to design the adaptive signal generator and the co efficient update circuit for a single sinusoid detection adaptive filter ba sed on the proposed method. Lastly, the convergence and the output error ch aracteristics of the proposed adaptive decimation filter are examined by a computer simulation example. (C) 2000 Scripta Technica.