Pitch detectors are used in a variety of speech processing applications such as speech recognition systems where the pitch of the speaker is used as one parameter for identification purposes. Furthermore, pitch detectors are also sued with adaptive filters to achieve high quality adaptive noise cancellation of speech signals. In voice conversion systems, pitch detection is an essential step since the pitch of the modified signal is altered to model the target voice. This paper describes a VLSI implementation of the computationally efficient and accurate pitch detection algorithm known as the Average Magnitude Difference Function (AMDF). The superior speed of a hardware pitch detect6or is essential particularly for use in real-time signal processing devices such as mobile phones.