COMPARISON OF ANALOG-BASED PROCESSORS AND SOFTWARE-BASED PLUG-IN PROCESSORS

1 - The basics

The advent of single-chip programmable digital signal processors (OSP) has expanded digital signal processing into automotive applications. Digital signal processors, compatible in cost to general-purpose microcomputers, offer much higher throughput in performing computationally intensive tasks. Because of this advantage, closed loop control, adaptive control, and digital audio processing can now be implemented in a cost effective manner. Some of the DSP automotive applications include combustion feedback engine control, active suspension systems, anti -skid brakes incorporating traction control and digital audio-based entertainment systems. The availability of digitaI signal processors i s changing many aspects of automotive designs. Early adopters of this technology for innovative automotive products wiII enjoy leadership and financial benefits over their competition. The impact of DSP to the automobile has just begun and will continue beyond the year 2000 ( I ) . This new technology has also presented tremendous challenges to both automotive and semiconductor industries. This paper first discusses digital signal processing characteristics. After reviewing historical digital signal processing solutions, the paper focuses on single-chip programmable digital signal processors and compares their architectural designs to general- purpose microprocessors and microcontrollers. Deficiencies of early digital signal processors are discussed and trends of DSP are explored. Performance and cost benefits of using DSP in digital control systems are explained. Automotive applications of digital signal processors are discussed in areas of powertrain, body and chassis control, and entertainment systems. The last part of the paper discusses the challenges presented to both automotive industry and semiconductor vendors.

In this chapter the evolution of analogue sampled-data techniques has been reviewed. The switched-capacitor technique has been seen to dominate in general purpose applications, whilst CCDs are being used extensively in imaging arrays. The emergence of mixed-mode analogue and digital signal processing and the subsequent need to integrate analogue sampled-data circuits on a digital VLSI process was identified. It was then seen that switched capacitors are not fully compatible with digital VLSI technology and that advances in technology will degrade their performance. Finally, the use of switched-current circuits, as a digital process compatible analogue sampled data signal processing technique, has been identified and this forms the basis of this text.

Three dimensional system integration offers the ability to stack multiple dies, fabricated in disparate technologies, within a single IC. For this reason, it is gaining popularity for use in sensor devices which perform concurrent analogue and digital processing, as both analogue and digital dies can be coupled together. One such class of devices are closed-loop neuromodulators; neurostimulators which perform real-time digital signal processing (DSP) to deliver bespoke treatment. Due to their implantable nature, these devices are inherently governed by very strict volume constraints, power budgets, and must operate with high reliability. To address these challenges, this paper presents a low-power inductive coupling link (ICL) transceiver for 3D integration of digital CMOS and analogue BiCMOS dies for use in closed-loop neuromodulators. The use of an ICL, as opposed to through silicon vias (TSVs), ensures high reliability and fabrication yield in addition to circumventing the use of voltage level conversion between disparate dies, improving power efficiency. The proposed transceiver is experimentally evaluated using SPICE as well as nine traditional TSV baseline solutions. Results demonstrate that, whilst the achievable bandwidth of the TSV-based approaches is much higher, for the typical data rates demanded by neuromodulator applications (0.5-1 Gbps) the ICL design consumes on average 36.7% less power through avoiding the use of voltage level shifters.

The High Efficiency Neutron Detector Array (HENDA) project at the Spallation Neutron Source (SNS), Oak Ridge Tennessee, has driven the need for state of the art radiation detector readout electronics. Readout electronics of this class must support multi-channel inputs while providing a high level of integration and precision. The Patara II ASIC targets this need by integrating a charge sensitive front end followed by analog and digital signal processing that supports the connectivity of 64 detectors. A monolithic biasing system and digital programmability was integrated in order to reduce the amount of required external components on the end system motherboard.

The development of modern technologies has fundamentally transformed the field of radar signal and data processing. With the use of advanced algorithms and computational power, radars are now capable of extracting crucial information from received signals, facilitating improved target identification and tracking. This article presents some of the advanced technologies employed in radar signal and data processing and their impact on adaptability of radar systems. It traces the evolution of radar technology from old systems to the present, emphasizing the benefits of adaptive radar signal processing, which includes algorithms such as adaptive beamforming, Space-Time Adaptive Processing, and the integration of Machine Learning and Artificial Intelligence. In conclusion, challenges, and future prospects in the field of radar systems are discussed, with a focus on the potential integration of Artificial Intelligence methods, Cognitive radars, and Multiple Input Multiple Output technologies. Despite technical obstacles, opportunities emerge to enhance the performance of radar systems and achieve new levels of efficiency.

This paper emphasizes on the design of a fully integrated low-power mixed-signal demodulator for multi-gigabit operations in 90 nm CMOS technology. A 3-bit ADC can be used to convert the analog inputs to digital form. But these baseband ADC's experience clipping distortions. This can be reduced by employing wide automatic gain control (AGC). The front-end of the system includes IQ mixers, a QVCO, frequency synthesizer, and AGC. This constitutes the analog block of the demodulator. AGC consists of Variable Gain Amplifier (VGA), power detector circuit, Differential to single ended amplifier and Operational amplifier. 6-bit current steering DAC is used to digitally control the output power of VGA. In order to recover OOK modulated signals, the analog signal processor (ASP) is used. This paper focuses on the design of fully integrated receiver consisting of broadband demodulator with embedded analog and digital signal processors in deep-submicron CMOS technology.

Magnetic-bearings, which support shafts with magnetic levitation rather than mechanical contact, have been in industrial use for decades. Recent technological developments, especially in digital processing and control, have made magnetic bearings a more-robust and cost-effective design solution than ever. The dynamic characteristic of electromagnetic bearing depends upon adopted controller; the active control can makes the electromagnetic bearings to realize complex control and special control. With the development of signal processing technology and modern control theory, the main parts of the control system are the digital signal-processing (DSP) electronics, a power supply, and amplifiers. An Active Magnetic Bearing (AMB) controller is mainly discussed in the paper, which is to be solved to realize this flexible control by hardware design based on DSP using TMS320C32 processor. It is proved by experiment that this kind of controller can optimize for this system, improve its stability and also have a very important referential value on the further study of AMB system.

Lab 9 - DSP Integration Examples

SCD has developed a series of Infra Red (IR) detectors based on the well established technologies of InSb diodes and the most advanced analogue and digital signal processors. These detectors exhibit great advantages for Missile Warning System (MWS). Their special modes of operation combined with a high level of performance enable efficient optimization for MWS applications. These high-end applications require special features including large dynamic range, high frame rate, high sensitivity at low signal and dual-color detection. The first detector that was developed for MWS applications is the "Blue Fairy" detector which has 320x256 elements. After the "Blue Fairy" a new generation of digital detectors was developed, starting with "Sebastian". Sebastian is based on a novel digital Focal Plane Processor (FPP) with formats of 640×512 and 480×384 elements. A detector based on two Sebastian Focal Plane Arrays (FPAs) assembled on a single substrate with a high degree of registration provides a good dual-color solution for MWS systems. In this paper the special features and the performance of all these detectors are presented showing their advantages for MWS applications.

Many circuit functions can now be realized using digital rather than analog techniques. The application of digital signal processing (DSP) technology for the implementation of the feedback control loop of a scanning tunneling microscope is discussed. A system that utilizes a commercially available PC AT-compatible plug-in card based on the Texas Instruments TMS320 series of digital processing chips to implement a loop controller of the proportional-integral-differential type is described. The advantages afforded by DSP in comparison to analog systems include greater flexibility in the choice of the signal processing algorithm and greater ease of control of loop parameters by the host computer.

This article has discussed the development of a three-axis attitude digital controller for an artificial satellite using a digital signal processor. The main motivation of this study is the attitude control system of the satellite Multi-Mission Platform, developed by the Brazilian National Institute for Space Research for application in different sort of missions. The controller design was based on the theory of the Linear Quadratic Gaussian Regulator, synthesized from the linearized model of the motion of the satellite, i.e., the kinematics and dynamics of attitude. The attitude actuators considered in this study are pairs of cold gas jets powered by a pulse width/pulse frequency modulator. In the first stage of the project development, a system controller for continuous time was studied with the aim of testing the adequacy of the adopted control. The next steps had included an analysis of discretization techniques, the setting time of sampling rate, and the testing of the digital version of the Linear Quadratic Gaussian Regulator controller in the MATLAB/SIMULINK. To fulfill the study, the controller was implemented in a digital signal processor, specifically the Blackfin BF537 from Analog Devices, along with the pulse width/pulse frequency modulator. The validation tests used a scheme of co-simulation, where the model of the satellite was simulated in MATLAB/SIMULINK, while the controller and modulator were processed in the digital signal processor with a tool called Processor-In-the-Loop, which acted as a data communication link between both environments.function and required time to achieve a given mission accuracy are determined, and results are provided as illustration.

This chapter briefly overviews the digital signal processing with an outline of introduction and importance of biomedical signal processing. Biomedical signal processing plays an important role in analysis of human body. For this, bioelectric potential needs to be recorded digitally and processed through digital processing system. In general, all the real-world signals are analog in nature. Initially, these analog signals are converted into digital signals, and then digital filters and other signal processing techniques are applied over them. Same is also followed in case of biomedical signals. A brief overview of this conversion process is also given in this chapter. Mainly, this chapter explores about generation process, recording, signal processing and common problems of electrocardiogram (ECG), electroencephalogram (EEG), electromyogram (EMG), and electrooculogram (EOG) signals. Real signals are also visualized that are taken from known datasets. This chapter provides a good base for any beginner in the field of biomedical signal processing.

Testing optical transponders for multi gigabit rate is demanding but to do so for production volumes requires novel approaches to high-speed data verification and processing is at the limits of instrument technology. Conventional sampling oscilloscopes are limited in such volume-production environment, and their ability to process data by virtue of digital signal processing DSP. Digital signal processing of sampled data is possible when the sampling rate is greater than twice the spectral content in the signal, this is not possible to perform for multi gigabit rate signals, based on the physical limitations of the today's state of the art sampling technology that uses e.g., gallium arsenide semiconductor technology. In the vector sampling method developed here, the amplitude, phase, and history of each sample are used to reconstruct the original signal and enable digital processing of various parameters of the signal that include jitter, spectral characteristics, digital low pass filtering for specific bit rate, and other critical parameters that affect the quality of signal transmission and the error rate. The reconstructed waveform in continuous discrete time enables are then processed and enable the same measurement capabilities of high speed sampling scopes with the advantage of the higher bandwidth. Performance examples of various test functions of jitter and eye diagrams will be given for comparison with conventional techniques.

Rogowski coils represent an attractive solution for AC current measurement, since they feature a wide bandwidth, high degree of galvanic insulation, and low cost compared to traditional measuring system like shunts and current transformers. The drawback in their use is represented by the need for integrating the EMF picked up at their terminals. The integration of the EMF signal is classically obtained by an analog integrator. problems related to the availability of suitable electronic integrator circuits usually limit the use of the Rogowski coil in the field of very large currents and/or very fast electrical transients. In a recent work, the authors developed a new integration process of the EMF signal induced in the coil, using digital signal processing. Since this approach was based on a data acquisition board and a PC, it was not suitable for industrial application. For this reason, we propose a novel and improved integration process, still based on a simple digital signal processing but implemented now in a stand alone board. The new system is characterized by accuracy and stability levels of the output signal well suitable for the majority of industrial applications, especially when low-amplitude and low-frequency current measurements are considered.