Speech voicing classification and pitch detection are fundamental techniques in speech analysis. Voicing information provides valuable insights into the nature of the excitation source used in speech production, and the pitch information is useful to many speech processing applications. In 1972 John Markel developed a technique which combines the benefits of inverse linear predictive (LPC) analysis and simple short-time autocorrelation to extract essential speech parameters. The research resulted in the simplified inverse filter tracking (SIFT) algorithm to make voiced/unvoiced classification of speech signals and determine the pitch period. Up until now this algorithm was used in various software algorithms only. However, this paper describes a real-time CMOS hardware implementation of this algorithm small enough to be implemented into various mobile communications equipment.