This project shows some selected signal techniques, including image and audio processing, using the Matlab digital signal processing and image processing toolboxes. The project is divided to 3 parts. Part I includes design and implementation of different types of filters for filtering signal that has different sinusoidal frequency components or noise. Part II examined audio filtering in the sense of specific frequency suppression and extraction. Part III deals with image processing; the project shows examples in smoothing, sharpening, and edge detection.