What is Digital Signal Processing (DSP)?

Ⅰ.  What is the DSP?

DSP refers to digital signal processing technology  , DSP chip refers to the chip that can realize digital signal processing technology,  DSP chip is a fast and powerful microprocessor, which is unique in that it can process data instantly. In the DSP chip, the program and data are separated by harvard structure, with special hardware multiplier, which can be used to quickly implement various digital signal processing algorithms. In today's digital era, DSP has become the basic device in communication, computer, consumer electronics and other fields.

The birth of DSP chip is the need of The Times. Since the 1960s, with the rapid development of computer and information technology, digital signal processing technology  arises at the historic moment and gets rapid development. Before the advent of DSP chip digital signal processing can only rely on microprocessor to complete. However, due to the low processing speed of the microprocessor, it can not meet the high speed real-time requirements of more and more information. Therefore, the application of faster and more efficient signal processing methods has become an increasingly urgent social demand.

In the 1970s, the theory and algorithm basis of DSP chip was mature. But at that time, DSP only stayed in the textbooks, even the developed DSP system  is composed of discrete components, its application field is limited to the military, aerospace departments.

In 1978, AMI company released the world's first single-chip DSP chip S2811, but there is no hardware multiplier required by modern DSP chip;

In 1979, the commercial programmable device 2920 released by  Intel  corporation is a major milestone of DSP chip, but it still has no hardware multiplier;

In 1980, THE MPD7720  introduced by  NEC  of Japan was the first commercial DSP chip with hardware multiplier, which was considered as the first single-chip DSP device.

In 1982, the first generation OF DSP chip TMS32010  and its series products were born in the world. This DSP device is made of NMOS technology with micron technology. Although the power consumption and size are slightly larger, the calculation speed is dozens of times faster than the microprocessor. The advent of DSP chip is a milestone, which marks a big step forward from large DSP application system to miniaturization. In the mid-1980s, with the ADVENT of CMOS DSP chip, its storage capacity and operation speed have been doubled, become the basis of voice processing, image hardware processing technology.

In the late 1980s, the third generation of DSP chips came out. The computing speed is further improved, and its application scope is gradually expanded to the fields of communication and computer.

The 1990s saw the fastest development of DSP, with the fourth and fifth generation of DSP chips appearing successively. Compared with the fourth generation, the system of the fifth generation is more integrated, integrating the DSP core and peripheral components on a single chip.w

In the 21st century, the sixth generation of DSP chips was born. The sixth generation chip in the performance of the fifth generation chip, based on the different commercial purposes of the development of a lot of personalized branches, and began to gradually expand new fields.

Ⅱ.  Application field of DSP chip

DSP chip emphasizes the real time of digital signal processing. DSP, as a digital signal processor, converts analog signals into digital signals for high-speed real-time processing by a dedicated processor. It has high-speed, flexible, programmable, low power consumption interface functions, in graphics and image processing, speech processing, signal processing and other communication fields play an increasingly important role.

Figure. 1 Application of DSP Chip in Market

There are many application fields of DSP, and new application fields are expected to emerge endlessly in the future. According to the statistics of the authoritative information company in the United States, DSP chip is the most widely used in the market, accounting for 56.1%; Followed by computer field, accounting for 21.16%; Consumer electronics and automatic controls accounted for 10.69%; Military/aviation 4.59%; Instrumentation accounted for 3.5%; Industrial control accounted for 3.31%; Office automation accounted for 0.65%.

1) Application of DSP chip in multimedia communication field.

The amount of information generated by media data transmission is huge, and multimedia network terminals need to quickly analyze and process the amount of information acquired in the whole process, so DSP is used in voice coding, image compression and reducing voice communication. Nowadays DSP produces real-time effect for speech decoding calculation, and the design protocol requirements have become the most basic international standard.

2) Application of DSP chip in industrial control field.

In the field of industrial control, industrial robots are widely used, and the performance requirements of robot control system are getting higher and higher. Real-time performance is the most important part of robot control system. When completing an action, more data and computational processing will be generated. High-performance DSP can be used here. DSP by applying to the robot control system, make full use of real-time computing speed characteristics of itself, make robot system can quickly deal with the problem, as to improve speed of DSP digital signal chip, easy to form parallel processing in the system network, greatly improve the performance of the control system makes the robot system to get a broader development.

3) Application of DSP chip in instrumentation field.

The rich in-chip resources of DSP can greatly simplify the hardware circuit of instrument and realize the  SOC  design of instrument. The measuring precision and speed of instrument are important indexes, which can be greatly improved by using DSP chip. For example, TI  's  TMS320 F2810 has an efficient 32-bit CPU core, A 12-bit A/D converter, rich on-chip memory and flexible command system, which sets up A broad platform for high precision instruments. High precision instruments have now developed into an important application of DSP, which is in the period of rapid spread and will promote technological innovation in the industry.

Figure. 2 The TMS320 Chip of Texas Instruments

4) Application of DSP chip in the field of vehicle safety and unmanned driving.

Increasingly advanced automotive electronic systems, such as infrared and millimeter wave radars, will require DSP analysis. Nowadays, with more and more cars, anti-collision system has become a research hotspot. Moreover, the image data captured by the camera needs to be processed by DSP before it can be displayed in the driving system for the reference of the driver.

5) Application of DSP chip in military field.

DSP's low power consumption, small size and real-time response speed are especially needed in weapons and equipment. Such as airborne air-to-air missile, equipped with infrared detector and corresponding DSP signal processor and other parts in a limited volume to complete the automatic locking and tracking of the target. The visual sights on the advanced fighter aircraft and the helmet-type lmer carried by infantry individuals need DSP technology to complete image filtering and enhancement, and intelligently search and capture targets. DSP technology is also used in automatic gun control, cruise missile, early warning aircraft, phased array antenna and other radar digital signal processing.

The high-end market is dominated by foreign companies

At present, there are three major DSP chip manufacturers in the world: Texas Instruments (TI), Analog Components (ADI) and Motorola. Among them, TI  takes the lead and occupies most of the international market share.  ADI  and Motorola also have certain market share.

Texas Instruments (TI) is recognized as the leader of DSP industry, the company successfully launched its first generation DSP chip TMS32010  in 1982, because the TMS320 series DSP chip has the characteristics of low price, easy to use, powerful function and so on. Therefore, it has gradually become the most influential and successful DSP series processor.

Among the three main series of TI  company, THE C2000 series now occupies a small market share, and the DSP products on TI  official website are mainly C6000 and C5000. TI  's three main DSP product series are C2000 series mainly used in digital control system; C5000 (C54x, C55x) series are mainly used for low power consumption and portable wireless communication terminal products. The C6000 series is mainly used in high-performance and complex communication systems. The TMS320C54x DSP chip in C5000 series is widely used in communication and consumer electronics.

The main products of C6000 series are:  C6000 DSP +ARM processor (12) -- OMAP-L1X (5), 66AK2x (7);  C6000 DSP (94) -- C674xDSP (5), C66x DSP (11)

The main product of C5000 series is: C55x ULTRA-low power DSP, which provides efficient signal processing for ultra-low power compact embedded products.

TI's DSP products are mainly used in machine vision, avionics and defense, size, Weight and Power consumption (SWAP), audio and video encoding/decoding and biometrics.

At present,  ADI company has six main products, respectively applied in the fields of voice processing, image processing, process control, measurement and control and measurement.

ADI focuses on DSP products and applications

MOTOROLA is also the world's largest PRODUCER of DSP chips, including fixed point and floating point, dedicated and general purpose, 16 and 24 bit and 32 bit. DSP chip is mainly used in speech processing, communication, digital camera, multimedia, control and other fields. The main products are  DSP56000  series, DSP56800 series, DSP56800E series, MSC8100 series, DSP56300 series, etc.

In the future, DSP technology will continue to develop and update in the following aspects:

1) DSP core integration is getting higher and higher.

It has always been the development trend of DSP technology to reduce the size of DSP chip. Currently, most of them are based on  RISC  structure. With the introduction of new technology, more and more manufacturers begin to improve DSP core, and integrate multiple DSP core, MPU core and peripheral circuit units into one chip. DSP system  level integrated circuit is realized. 

2) Programmable DSP chip will be the dominant product in the future.

With the need of personalized development, DSP programmable for manufacturers to provide more flexibility, to meet the manufacturers in the same DSP chip to develop more different models and characteristics of the series of products, but also make the majority of users for DSP upgrade. For example, refrigerators and washing machines, which used to be equipped with microcontrollers, have now been replaced by programmable DSPS to control high-power motors.

3) Fixed-point DSPS dominate.

At present, among the DSP devices sold in the market, 16-bit fixed-point programmable DSP devices still occupy the mainstream products. With the continuous low cost of DSP fixed-point operation devices, the advantages of smaller and smaller energy consumption are becoming increasingly obvious. In the future, fixed-point DSP chips will still be the protagonist of the market.

Ⅲ.  FPGA chip VS DSP chip

FPGA is the field programmable gate array, as a semi-customized circuit in the field of ASIC, it not only solves the shortage of customized circuit, but also overcomes the shortcomings of the original programmable device gate circuit number is limited. With the FPGA chip, you can program a newly invented CPU core, embedded in the FPGA chip, and can be embedded in more than one.

Figure. 3 Basic Architecture of FPGA

The international FPGA market is monopolized by four giants, which are Celinth,  Altra, Mgosomme and Lattice.  Altra and Celings are the inventors of FPGA. Altra invented the world's first programmable logic device in 1983, and Celings launched the world's first FPGA product XC2064 in 1985. According to 2017 company financials,  Syrynx  had revenue of $2.349 billion,  Altera  (acquired by Intel) of $1.902 billion, THE MGOgor-Somme FPGA business of $421 million, and Lattice of $386 million. Together, Celins and Alterra account for almost 90% of the international market.

Figure. 4 Market Share of FPGA Four Giants in 2017

FPGA chip is different from DSP chip. DSP is a special microprocessor, suitable for conditional processes, especially for more complex multi-algorithm tasks. FPGA contains a large number of resources to realize combinational logic, which can complete large-scale combinational logic circuit design. At the same time, it also contains a considerable number of triggers, with which FPGA can accomplish complex sequential logic functions.

Figure. 5 Application Fields of FPGA Chip in 2016

FPGA chip is different from DSP chip. DSP is a special microprocessor, suitable for conditional processes, especially for more complex multi-algorithm tasks. FPGA contains a large number of resources to realize combinational logic, which can complete large-scale combinational logic circuit design. At the same time, it also contains a considerable number of triggers, with which FPGA can accomplish complex sequential logic functions.

The versatility of DSP chips is relatively weak, while that of FPGA is stronger.

DSP has the flexibility of software, while FPGA has the high speed of hardware.

DSP executes low speed events in series, but there may be some delay before processing, while FPGA cannot process multiple events, because each event has its own dedicated hardware, but each event can be executed at the same time by using this dedicated hardware.

DSPS are programmed as a sequential stream of instructions, whereas FPGAs are programmed as block diagrams, making it easy to look at the data stream.

It is also a trend of future design to combine DSP and FPGA, adopt DSP+FPGA structure, or embed DSP module into FPGA chip under the requirement of flexible structure and generality as well as complex algorithm.