Introduction to DSP Processor
What is a DSP?
Digital Signal Processors (DSP) take real-world signals like voice, audio, video, temperature, pressure, or position that have been digitized and then mathematically manipulate them. A DSP is designed for performing mathematical functions like "add", "subtract", "multiply" and "divide" very quickly.
Signals need to be processed so that the information that they contain can be displayed, analyzed, or converted to another type of signal that may be of use. In the real-world, analog products detect signals such as sound, light, temperature or pressure and manipulate them. Converters such as an Analog-to-Digital converter then take the real-world signal and turn it into the digital format of 1's and 0's. From here, the DSP takes over by capturing the digitized information and processing it. It then feeds the digitized information back for use in the real world. It does this in one of two ways, either digitally or in an analog format by going through a Digital-to-Analog converter. All of this occurs at very high speeds.
To illustrate this concept, the diagram below shows how a DSP is used in an MP3 audio player. During the recording phase, analog audio is input through a receiver or other source. This analog signal is then converted to a digital signal by an analog-to-digital converter and passed to the DSP. The DSP performs the MP3 encoding and saves the file to memory. During the playback phase, the file is taken from memory, decoded by the DSP and then converted back to an analog signal through the digital-to-analog converter so it can be output through the speaker system. In a more complex example, the DSP would perform other functions such as volume control, equalization and user interface.
A DSP's information can be used by a computer to control such things as security, telephone, home theater systems, and video compression. Signals may be compressed so that they can be transmitted quickly and more efficiently from one place to another (e.g. teleconferencing can transmit speech and video via telephone lines). Signals may also be enhanced or manipulated to improve their quality or provide information that is not sensed by humans (e.g. echo cancellation for cell phones or computer-enhanced medical images). Although real-world signals can be processed in their analog form, processing signals digitally provides the advantages of high speed and accuracy.
Because it's programmable, a DSP can be used in a wide variety of applications. You can create your own software or use software provided by ADI and its third parties to design a DSP solution for an application. For more detailed information about the advantages of using DSP to process real-world signals, please read Part 1 of the article from Analog Dialogue titled: Why Use DSP? Digital Signal Processing 101- An Introductory Course in DSP System Design.
DSP Processors are specialized microprocessor with an optimized architecture for the fast operational needs of digital signal processing.
NEED of DSP Architecture
Difference between DSP Processor and Microprocessor
|Sr No.||Parameters||DSP processor||Microprocessor|
|1||Instruction cycle||Instructions are executed in single cycle of the clock||Multiple clocks cycles are required for execution of one instruction.|
|2||Instruction execution||Parallel execution is possible.||Execution of instruction is always sequential.|
|3||Memories||Separate data and program memory.||No such separate memories are present.|
|4||On chip/Off chip memories||Program and Data memories are present on chip extendable off chip.||Normally on chip cache memory present, main memory is off chip.|
|5||Program flow control||Program sequencer and instruction register take care of program flow||Program counter take care of flow of execution.|
|6||Pipelining||Pipelining is implicate through instruction register and instruction cache.||Queuing is perform explicate by one queue register to support pipelining.|
|7||Operand Fetch||Multiple operands can be fetched simultaneously.||Operands are fetched sequentially.|
|8||Address and data bus multiplexing||Address and data bus are not multiplexed. They are separate on chip as well as off chip.||Address and data bus are multiplexed.|
|9||Computational units||Three separate computational units: ALU, MAC and shifter.||Only one main unit ALU.|
|10||On chip address and data bus||Separate address and data bus for program and data memory.||Address and data bus are the two buses on the chip|
|11||Addressing modes||Direct and indirect addressing modes.||Direct, Indirect, Register, Register indirect, Immediate addressing mode etc.|
|12||Application||Signal processing, audio processing, speech processing and array processing etc||General Purpose applications.|
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