Multirate signal processing is an enabling technology that brings DSP techniques to applications requiring low-cost and high sample rates. Field programmable gate arrays (FPGAs) provide system-level hardware solutions for signal processing architects demanding both high-performance and flexibility. This workshop provides an introduction to the fundamental theory of multirate filter techniques and provides simple descriptions of polyphase decimators and interpolators. Wavelet theory has development roots in both mathematics and signal processing communities. In this paper we will explain wavelet theory from both a signal expansion and filter bank viewpoint. Classes of signal processing problems that can benefit from wavelet techniques will be presented with simple examples. Implementation of mulitrate filters and wavelet structures with FPGAs will be explained for real time applications.