Digital Signal Processing The acronym DSP can stand for one of two things: digital signal processing which refers to the technique used to process signals digitally or digital signal processor which would refer to a specialized kind of microprocessor. Since the introduction of general-purpose microprocessors in the 1980’s, a wider range of modern technology now includes digital signal processing technology. This includes cellular phones, CD players, computers, DVD players, video recorders, computer monitors, and many other similar devices. DSP is also taking over analog circuitry in TV sets and telephones. One of DSP’s major applications is signal compression and decompression. Signal compression enables things such as call waiting and image projection on computer screens. DSP involves a great deal of math, both complex and simple. The design of a DSP chip enables it to perform these functions very rapidly which produces hundreds of millions of samples very quickly. This provides “real time” performance meaning the signal is live. This can be seen in loud speakers and cell phones. Most major electronics companies utilize DSP in their technology including Texas Instruments, Intel, and Motorola. An example of “real time” performance could be viewed in a lab that we did. We had two separate groups: one group made a “receiver” and the other group made a “transmitter.” Across the room, one group had their receiver and set up the microphone on a stand a certain amount of space from the other group’s speakers. When our groups were ready, the transmitting group would hit a key on the keyboard. Once the key was hit, a pitch would make its way out of the speakers and the microphone would receive and “decode” and form a letter on the screen. Once we perfected and got the microphone and speakers the right distance and the right volume, we could type sentences slowly and see them on the other screen. Every once in a while there would be interference and we would get a mixed up letter and throw us off a little. Although the concept of DSP and what it entails is quite complex, it is an integral part of every day modern technology. Digital signal processing has evolved heavily from its humble beginnings. Back in the Stone Age, when computers filled whole rooms, it would take a day to receive a signal analysis. Since then, computers have become more compact and considerably faster. What it used to take a day to do, it now takes a fraction of a second to do. Signal processing is a more basic form of DSP, and it means just what it says: a signal is manipulated in some way to produce a brand new signal. Signal processing has been around since the debut of electronics. Signal processing in its most basic form could be quite simply amplification or filtration. Considering this most basic form of signal processing, digital processing is slightly easier to comprehend. Digital signal processors accomplish this manipulation of signal, but they require a few things in order to do so. First and foremost, the processor must be fast and precise enough to sustain the mathematics involved in the process. The processor must also have enough memory necessary to store programming, samples, and intermediate and final results. The processor must also obviously have digital-to-analog and analog-to-digital converters. Finally, the processor must have the necessary programming. Even the simplest digital signal processors require these four components. While it is important to know the components of a processor, it is also important to know how one works. There are four basic steps to digital signal processing. Some kind of input is sampled repeatedly in a single second. The frequency and amplitude of the signal is then converted to a digital representation of the original form. This results in a stream of digital raw data that can be computed by the digital signal processor, and the job is done. This process is found in all different types of technology, but it comes in three major forms. One of these forms of the process is built-in DSP. This can be found in the technology of most modern radio stations. Another application of DSP is the external DSP unit. It uses the computer-controlled algorithms to perform four main tasks: random noise reduction, adaptive multi-tone notch filtering, bandbass filtering, and RTTY remodulation. Finally, there is also DSP software. It runs well but with a slight delay. These pieces of technology are where DSP can be witnessed on a more specific level. In conclusion, we use digital signal processing every day without ever being aware of doing so. When we are speaking on our cell phones or watching TV, we are utilizing digital signal processing, and when we communicate via webcam, we are doing so courtesy of algorithms and DSP. We fail to realize the complexity that is truly involved in tasks we find so simple to perform. Works Cited
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