Digital signal processor

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A digital signal processor chip found in a guitar effects unit.

A digital signal processor (DSP) is a specialized microprocessor (or a SIP block), with its architecture optimized for the operational needs of digital signal processing.[1][2]

The goal of digital DSP signal processors is usually to measure, filter or compress continuous real-world analog signals. Most general-purpose microprocessors can also execute digital signal processing algorithms successfully, but dedicated DSPs usually have better power efficiency thus they are more suitable in portable devices such as mobile phones because of power consumption constraints.[3] DSPs often use special memory architectures that are able to fetch multiple data or instructions at the same time.


A typical digital processing system


Most general-purpose microprocessors and operating systems can execute DSP algorithms successfully, but are not suitable for use in portable devices such as mobile phones and PDAs because of power efficiency constraints.[3] A specialized digital signal processor, however, will tend to provide a lower-cost solution, with better performance, lower latency, and no requirements for specialised cooling or large batteries.[citation needed]

Such performance improvements have led to the introduction of digital signal processing in commercial communications satellites where hundreds or even thousands of analog filters, switches, frequency converters and so on are required to receive and process the uplinked signals and ready them for downlinking, and can be replaced with specialised DSPs with a significant benefits to the satellites' weight, power consumption, complexity/cost of construction, reliability and flexibility of operation. For example, the SES-12 and SES-14 satellites from operator SES, both intended for launch in 2017, are being built by Airbus Defence and Space with 25% of capacity using DSP.[4]



Software architecture[edit]


One implication for software architecture is that hand-optimized assembly-code routines are commonly packaged into libraries for re-use, instead of relying on advanced compiler technologies to handle essential algorithms.[clarification needed] Even with modern compiler optimizations hand-optimized assembly code is more efficient and many common algorithms involved in DSP calculations are hand-written in order to take full advantage of the architectural optimizations.

Instruction sets[edit]

Data instructions[edit]

  • Saturation arithmetic, in which operations that produce overflows will accumulate at the maximum (or minimum) values that the register can hold rather than wrapping around (maximum+1 doesn't overflow to minimum as in many general-purpose CPUs, instead it stays at maximum). Sometimes various sticky bits operation modes are available.
  • Fixed-point arithmetic is often used to speed up arithmetic processing
  • Single-cycle operations to increase the benefits of pipelining

Program flow[edit]

Hardware architecture[edit]



Memory architecture[edit]



Addressing and virtual memory[edit]



Prior to the advent of stand-alone DSP chips discussed below, most DSP applications were implemented using bit-slice processors. The AMD 2901 bit-slice chip with its family of components was a very popular choice. There were reference designs from AMD, but very often the specifics of a particular design were application specific. These bit slice architectures would sometimes include a peripheral multiplier chip. Examples of these multipliers were a series from TRW including the TDC1008 and TDC1010, some of which included an accumulator, providing the requisite multiply–accumulate (MAC) function.

In 1976, Richard Wiggins proposed the Speak & Spell concept to Paul Breedlove, Larry Brantingham, and Gene Frantz at Texas Instrument's Dallas research facility. Two years later in 1978 they produced the first Speak & Spell, with the technological centerpiece being the TMS5100,[5] the industry's first digital signal processor. It also set other milestones, being the first chip to use Linear predictive coding to perform speech synthesis.[6]

In 1978, Intel released the 2920 as an "analog signal processor". It had an on-chip ADC/DAC with an internal signal processor, but it didn't have a hardware multiplier and was not successful in the market. In 1979, AMI released the S2811. It was designed as a microprocessor peripheral, and it had to be initialized by the host. The S2811 was likewise not successful in the market.

In 1980 the first stand-alone, complete DSPs – the NEC µPD7720 and AT&T DSP1 – were presented at the International Solid-State Circuits Conference '80. Both processors were inspired by the research in PSTN telecommunications.






Modern DSPs[edit]









Microchip Technology produces the PIC24 based dsPIC line of DSPs. Introduced in 2004[7], the dsPIC is designed for applications needing a true DSP as well as a true microcontroller, such as motor control and in power supplies. The dsPIC runs at up to 40MIPS, and has support for 16 bit fixed point MAC, bit reverse and modulo addressing, as well as DMA.



Embedded general-purpose RISC processors are becoming increasingly DSP like in functionality. For example, the OMAP3 processors include a ARM Cortex-A8 and C6000 DSP.


In May 2018, Huarui-2 designed by Nanjing Research Institute of Electronics Technology passed acceptance. With a processing speed of 0.4 TFLOPS, the chip can achieve better performance than current mainstream DSP chips[8]. The design team has began to create Huarui-3, which has a processing speed in TFLOPS level and a support for AI[9].

See also[edit]


  1. ^ Dyer, S. A.; Harms, B. K. (1993). "Digital Signal Processing". In Yovits, M. C. Advances in Computers. 37. Academic Press. pp. 104–107. doi:10.1016/S0065-2458(08)60403-9. ISBN 9780120121373. 
  2. ^ Liptak, B. G. (2006). Process Control and Optimization. Instrument Engineers' Handbook. 2 (4th ed.). CRC Press. pp. 11–12. ISBN 9780849310812. 
  3. ^ a b Ingrid Verbauwhede; Patrick Schaumont; Christian Piguet; Bart Kienhuis (2005-12-24). "Architectures and Design techniques for energy efficient embedded DSP and multimedia processing" (PDF). Retrieved 2017-06-13. 
  4. ^ Beyond Frontiers Broadgate Publications (September 2016) pp22
  6. ^ Bogdanowicz, A. (2009-10-06). "IEEE Milestones Honor Three". The Institute. IEEE. Retrieved 2012-03-02. 
  7. ^ "PIC microcontroller". Wikipedia. 2018-02-04. 

External links[edit]