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Digital Signal Processing Page

    General information

    DSPs are special microprocessors designed to executerepetitive math-intensive algorithms. Today many embeddedapplications require both types of processors. Digital Signal Processors have approximately the same level ofintegration, the same clock frequencies as general purposemicroprocessors. Pn signal processing tasks DSPs overtake general purpose processors from 2 to 3 order in speed. This is because of architectural differences. Typical DSP application fields are audio signal processing, video signal processing and telecommunications devices. Digital signal processing requires a large amount of real-timecalculations. The most common operation in digital signal processing is thesum of products calculation. Among such operations are well known convolution and Discrete Fourier Transform. Digital Signal Processors vs. Universal Microprocessors 9To increase the speed, digital signal processors usually havemany specialized arithmetic units, which can operatesimultaneously. To calculate the sum of products, typical DSPoperation, all DSPs have multiplier and accumulator and twooperations multiplication and addition can be implemented duringone cycle. Some DSPs can fulfil simultaneously even FFTbutterfly. All DSPs contain shifter to shift operands without lossadditional time.Digital Signal Processors are designed for realtimecalculation. Fixed sampling rate leads to necessity to haveregular instruction cycle. Such regular instruction cycle is achievedin RISC (reduced instruction set computer) microprocessors byrestricting the instruction set. But in DSP the same is achieving byhardware increasing the speed of important complex instructions,for example multiplications.Universal microprocessors were designed simple and cheappersonal computers. Universal CISC (complex instruction set computer)microprocessors have a large variety of command cycle duration. For example in 8086 microprocessor addition - 3 clocks and multiplication -more 100 clocks.Some features of DSP in are included in recent universal microprocessors, which makes the leaster processor capable of supporting many applications which earlier needed special DSPs.


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