Since there origin as room-filling devices, they have allowed mankind to accomplish tasks that seemed impossible. In the early twentieth century, nobody fathomed that we could send someone into outer space and we sent someone to the moon. This was made possible by computers but more importantly, signals. Without signals there would have been no possible way for the astronauts to stay in communication with earth. With the use of signals and computers this was made possible.
Digital Signal Processing is the science of using computers to understand signals. Signals are found in many cases in our ordinary life. It's found in your must-have cell phone, your HDTV, and your camera. It's used in the military, in such cases as radar and sonar, "smart" bombs, and in every vehicle. DSP accomplishes a wide variety of objectives such as filtering, speech recognition, image enhancement, data compression, neural networks, and much more.
One widely used device that uses Digital Signal Processing is the Compact Disk. This revolution in music changed the way music can be reproduced. CD's music quality far exceeds the quality of its predecessors, the record and audiotape. The CD works by storing the music on it main surface, which is shiny. The digital information is stored in a series of pits burned on the surface with a laser. .
When the CD is played, an optical sensor detects if the surface is reflective or nonreflective. This information is correct with Eight-to-Fourteen Modulation (EFM) and Reed-Solomon encoding. This corrected information is converted to stereo analog signals, which can be heard by the human ear.
EFM is an encoding scheme that takes eight-bit information and converts it to 14-bit information and also 14 bits to back eight bits. 14-bit information is essential for storing data on a CD. During playback the 14 bits get converted to 8 bits. .
Reed Solomon encoding involves combining the data and left and right stereo channels for error detection and correction.
