Digital Signal Processors (DSP)

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Digital Signal Processors (DSP's) - Page 2 of 2

A DSP is also very similar to a microprocessor as far as architecture is concerned, i.e., it has many parts that are also seen in a microprocessor, such as data and address buses, an Arithmetic-Logic Unit (ALU), a program control unit, assorted flags and registers, etc. It also has its own native instruction set, which defines what it can be programmed to do. Programming DSP's is no longer complicated too, with the existence of various development kits in the market that support DSP software development using high-level programming languages such as C.

Many DSP applications deal with real-world analog signals (such as sound, light, analog voltage, analog current, temperature, pressure). Since a DSP can only process digital signals, there is a need to convert analog signals first into digital data before they can be processed by a DSP. After processing, there is again a need for the DSP to convert these digital data back into the original real-world analog signal format. In such applications, the DSP must be supported by an analog-to-digital converter (ADC) and a digital-to-analog converter (DAC), which will perform the required analog-digital and digital-analog conversions, respectively.

Applications where DSP's are commonly used include: 1) digital sound and image processing; 2) digital communications; 3) consumer electronics (e.g., mobile phones, faxes, computer peripherals such as modems and sound cards, and digital entertainment systems such as DVD players and digital TV); 4) medical electronics; and 5) industrial and automation electronics.

There are currently four major companies that produce DSP's, namely, Texas Instruments, Analog Devices, Motorola, and Lucent Technologies. Examples of commercially available DSP's include:

- Analog Devices' ADSP-21xx: 10 to 50 MIPS 16-bit fixed-point DSP's; 40-bit accumulator; 24-bit instructions;

- Analog Devices' ADSP-2106x ("SHARC"): 40 MIPS, 32-bit floating point DSP's;

- Lucent Technologies' DSP32xx: 32-bit floating-point with 40-bit accumulator and 16/24-bit fixed point DSP's;

- Motorola's DSP568xx: 20 MIPS 16-bit fixed-point DSP's;

- Motorola's DSP96002: IEEE format floating-point DSP with two complete 32-bit data and address buses;
- Texas Instruments' TMS320C1x: Low cost fixed-point DSP's with 16-bit data, 32-bit registers;

- Texas Instruments' TMS320C8x: Multiple 50 MHz 32-bit fixed-point processors combined with a RISC supervisory processor in a single multi-chip module.

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