Digital Signal Processing Technology Research Articles

A CNN-based cost-effective modulation format identification scheme by low-bandwidth direct detecting and low rate sampling for elastic optical networks

Modulation format identification (MFI) is an indispensable technique in future optical performance monitoring (OPM) for elastic optical networks. The existing MFI scheme based on coherent detection combined with digital signal processing technology has good chromatic dispersion (CD) tolerance, but the high cost prevents its practical application at numerous intermediate nodes. By contrast, the existing direct detection-based MFI has the advantage of low cost but the CD tolerance is poor. In this paper a low-cost direct detection-based MFI scheme is proposed. The scheme not only reduces the cost of the MFI module by low-bandwidth direct detection and low rate sampling, but also ensures high MFI accuracy by extracting and learning features of asynchronous amplitude histograms (AAH) through convolutional neural network (CNN) as it has better accuracy and stability of identification compared with artificial neural network (ANN) and deep neural network (DNN) with the same computational complexity. A maximum correlation coefficient of AAH sequences of different modulation formats is proposed as a metric of discrimination for MFI, and its relationship with the bandwidth of MFI module is investigated in the scenario that the MFI module relative bandwidth changes from 0.00025 to 0.75 of service signal baud rate (SBR) and the CD vary from 0∼16000ps/nm. The simulation and experimental results show that the MFI module with 0.002∼0.02 SBR bandwidth could realize 100% MFI accuracy of three common QAM signals with the CD of 0∼16000ps/nm.

Research on Application of Digital Signal Processing Technology in Communication

With the continuous development of modern information technology and the continuous improvement of people’s living standards, electronic information technology has been widely used in people’s lives. People’s lives are inseparable from it. With its continuous development, its application range is getting wider and wider. This article first gives a brief overview of digital signal processing technology, analyzes the advantages and disadvantages of digital signal processing technology in the communication field, and the specific applications of speech compression coding and software radio in communication are analyzed in order to better promote the application of digital signal processing technology in the communication field.

Complex Dynamics of a Novel Chaotic System Based on an Active Memristor

On the basis of the bistable bi-local active memristor (BBAM), an active memristor (AM) and its emulator were designed, and the characteristic fingerprints of the memristor were found under the applied periodic voltage. A memristor-based chaotic circuit was constructed, whose corresponding dynamics system was described by the 4-D autonomous differential equations. Complex dynamics behaviors, including chaos, transient chaos, heterogeneous coexisting attractors, and state-switches of the system were analyzed and explored by using Lyapunov exponents, bifurcation diagrams, phase diagrams, and Poincaré mapping, among others. In particular, a novel exotic chaotic attractor of the system was observed, as well as the singular state-switching between point attractors and chaotic attractors. The results of the theoretical analysis were verified by both circuit experiments and digital signal processing (DSP) technology.

Compressed Neural Network Equalization Based on Iterative Pruning Algorithm for 112-Gbps VCSEL-Enabled Optical Interconnects

Advanced nonlinear digital signal processing technologies, which bring significant performance gain for high-speed optical interconnects, are highly constrained by huge complexity in the actual deployment. Fully connected neural network-based equalizer has shown powerful efficacy to deal with the complex linear and nonlinear impairments for VCSEL-enabled multi-mode optical interconnects, but it also contains a number of redundancies with little impact on performance improvement. In this article, we experimentally demonstrate a compressed neural network equalization using the iterative pruning algorithm for 112-Gbps VCSEL-enabled PAM-4 and PAM-8 transmissions over 100-m MMF. We also study the impact of threshold and pruning span on the performance of proposed algorithms. The results show up to 71% connection compression by use of the iterative pruning algorithms and maximum 28.4% improvement compared with the one-shot pruning algorithm.

Enabling Technology in High-Baud-Rate Coherent Optical Communication Systems

High-baud-rate coherent optical system is essential to support the ever-increasing demand for high-speed applications. Owing to the recent progress in advanced modulation formats, over 1 Tb/s single-carrier data transmission has been achieved in the laboratory, and its commercial application is envisioned in the near future. This paper presented the trend of increasing baud rate and utilizing high-order quadrature-amplitude modulation (QAM), and several enabling technologies in the coherent optical communication systems. We first discussed recent progress of high-order QAM system and digital signal processing technology. Furthermore, we compared the transmission performance of three different ultrahigh-order QAM formats. The paper then reviewed the commonly used methods of achieving over 100 GBaud optically modulated signals. Besides, five attractive modulators and their corresponding modulation structures are illustrated. Key performance parameters including electrode length, 3-dB bandwidth, half-wave voltage, extinction ratio and optical loss are also compared. Finally, the trade-off between the baud rate and QAM orders in implementing high-speed systems are investigated in simulations. The results show that for the coming 800 GbE or 1.6 TbE, PDM-64-QAM might be an idea choice by considering the trade-off between the link reach and required system bandwidth. By adopting the latest probabilistic shaping technology, higher-order QAM signals, such as PS PDM-256-QAM, could be favorable for long reach applications while using extra system bandwidth.

Research on Application of Digital Signal Processing Technology in Communication

With the continuous development of modern information technology and the continuous improvement of people's living standards, electronic information technology has been widely used in people's lives. People's lives are inseparable from it. With its continuous development, its application range is getting wider and wider. This article first gives a brief overview of digital signal processing technology, analyzes the advantages and disadvantages of digital signal processing technology in the communication field, and the specific applications of speech compression coding and software radio in communication are analyzed in order to better promote the application of digital signal processing technology in the communication field.

All-printed large-scale integrated circuits based on organic electrochemical transistors

The communication outposts of the emerging Internet of Things are embodied by ordinary items, which desirably include all-printed flexible sensors, actuators, displays and akin organic electronic interface devices in combination with silicon-based digital signal processing and communication technologies. However, hybrid integration of smart electronic labels is partly hampered due to a lack of technology that (de)multiplex signals between silicon chips and printed electronic devices. Here, we report all-printed 4-to-7 decoders and seven-bit shift registers, including over 100 organic electrochemical transistors each, thus minimizing the number of terminals required to drive monolithically integrated all-printed electrochromic displays. These relatively advanced circuits are enabled by a reduction of the transistor footprint, an effort which includes several further developments of materials and screen printing processes. Our findings demonstrate that digital circuits based on organic electrochemical transistors (OECTs) provide a unique bridge between all-printed organic electronics (OEs) and low-cost silicon chip technology for Internet of Things applications.

The Industry Digital Signal Processing Technology Standing Committee [In the Spotlight

The Industry Digital Signal Processing Technology Standing Committee [In the Spotlight

Low-Complexity Adaptive Chromatic Dispersion Estimation Scheme Using Machine Learning for Coherent Long-Reach Passive Optical Networks

In the coherent long-reach passive optical networks (LRPON), it is crucial to propose cost-effective digital signal processing (DSP) technologies to reduce the overall complexity and power consumption. This paper has proposed a low-complexity chromatic dispersion (CD) estimation scheme based on deep neural networks (DNN) and the error vector magnitude (EVM). To add comparisons, the performances of CD estimation schemes using other two well-known machine learning algorithms including the k-nearest neighbor (KNN) and the decision tree (DT) have also been investigated. The simulation results show that the proposed CD estimation scheme is effective in the coherent LRPON with the quadrature phase shift keying (QPSK) and 16-ary quadrature amplitude modulation (QAM) systems at 14Gbaud rate, 28Gbaud rate and 56Gbaud rate. The comprehensive performances of the DNN outperform those of the KNN and the DT. The mean estimation error of the DNN is less than 20ps/nm within the 100 km access distance in the 28Gbaud QPSK/16QAM systems. What's more, compared with classical methods using the CD scanning and frequent domain equalizers (FDE), the computation complexity of the proposed CD estimation scheme based on the DNN-EVM has been respectively reduced by 72.3 times, 86.7 times and 2.8 times about the amount of multipliers, adders and comparators.

A flexible and compact electronic system for the bolometric diagnostic with on-line calibration capability

At ENEA Frascati laboratories an updated electronic system for the bolometric diagnostic is under development. The system is based on the most recent electronic technology and it is able to manage a large number of channels. It is flexible, reliable and compact in order to be suitable for applications on large fusion experimental machines or reactors. The system has been conceived to be applied to bolometric detectors based on a resistive bridge, it is mainly based on the digital signal processing technology to guarantee high accuracy, large dynamic range and a high signal to noise ratio. It is also able to manage a large offset of the bridges. A further important feature of the system is the embedded calibration capability of the sensor detectors that allows for the calibration of each channel in parallel and in a very short time with the bolometer heads installed and without any manual intervention on the lay-out, thus also allowing for calibration just shortly before the plasma experiment. A further fast embedded on-line calibration capability allows for the estimation of the sensor temperature and of the temperature gradient in the bolometer head, inside the bolometer measurement temporal window. The paper describes the main concepts, the general architecture of the system and in detail the calibration and the on-line calibration functionalities.

Fault Diagnosis of Train Plug Door Based on a Hybrid Criterion for IMFs Selection and Fractional Wavelet Package Energy Entropy

The train plug door is the only way for passengers getting on and off. Its failures will make train operation ineffective. Taking the developed digital signal processing technologies into consideration, a data-driven diagnosis method for train plug doors is proposed based on sound recognition. First, a novel preprocessing method based on empirical mode decomposition and hybrid intrinsic mode functions (IMFs) selection criterion is proposed. The selected significant IMFs are used to reconstruct the signals. Inspired by the idea of fractional calculus, novel entropy named fractional wavelet package decomposition energy entropy (FWPDE) is proposed. Finally, multi-class support vector machine is used for classification and validation. Experimental results indicate that the proposed preprocessing method is of great significance to extract effective FWPDE features. In addition, FWPDE is more powerful in comparison with the classical wavelet package decomposition energy entropy. The identification accuracy using the proposed method reaches 96.28%, which demonstrates its effectiveness and superiority.

Coexisting Attractors and Multistability in a Simple Memristive Wien-Bridge Chaotic Circuit.

In this paper, a new voltage-controlled memristor is presented. The mathematical expression of this memristor has an absolute value term, so it is called an absolute voltage-controlled memristor. The proposed memristor is locally active, which is proved by its DC V–I (Voltage–Current) plot. A simple three-order Wien-bridge chaotic circuit without inductor is constructed on the basis of the presented memristor. The dynamical behaviors of the simple chaotic system are analyzed in this paper. The main properties of this system are coexisting attractors and multistability. Furthermore, an analog circuit of this chaotic system is realized by the Multisim software. The multistability of the proposed system can enlarge the key space in encryption, which makes the encryption effect better. Therefore, the proposed chaotic system can be used as a pseudo-random sequence generator to provide key sequences for digital encryption systems. Thus, the chaotic system is discretized and implemented by Digital Signal Processing (DSP) technology. The National Institute of Standards and Technology (NIST) test and Approximate Entropy analysis of the proposed chaotic system are conducted in this paper.

DSP Technology and Its Application in Fuze Signal Processing

The continuous innovation of the embedded digital signal processor (DSP) brings new opportunities for the breakthrough of fuze technology, so that the weapon system can complete the detection battlefield, precise control, high-efficiency damage without changing the existing shape and volume of the fuze. This paper first introduces the advantages and characteristics of DSP chips, then summarizes the application of DSP in a variety of fuze signal processing. Finally, the development direction and application trend of DSP in fuze are prospected.

Threshold-Based Pruned Retraining Volterra Equalization for 100 Gbps/Lane and 100-m Optical Interconnects Based on VCSEL and MMF

The high-speed multimode optical interconnects based on vertical-cavity surface-emitting laser and multimode fiber (MMF) are severely constrained by band-limited devices, modulation nonlinearity, and laser induced noises such as relative intensity noise, mode partition noise, and fiber-induced noises such as chromatic dispersion and mode dispersion. The advanced digital signal processing technologies have been viewed as the inevitable tool to mitigate the physical limitations of electrical and optical components and the noise interactions during the transmission. In order to achieve multimode 100 Gbps/lane over 100-m transmission with the existing devices, a Volterra equalizer has been proven as a very effective equalization solution to deal with nonlinear impairments. However, the practical implementation of this nonlinear equalizer has been constrained by its tremendously high computation complexity. In this paper, we propose the threshold-based pruned retraining Volterra equalization (TRVE) to reduce the computation complexity, while maintaining the transmission performance. Multimode 100-Gbps/lane transmission over 100-m OM3 MMF has been experimentally demonstrated with up to 70.7% computation complexity reduction, while keeping the bit error rate under the 7% hard-decision forward error correction limit. In addition, the TRVE with $\ell _1$ -regularization is also proposed and experimentally verified to optimize the threshold selection.

Recent Advances in Equalization Technologies for Short-Reach Optical Links Based on PAM4 Modulation: A Review

In recent years, short-reach optical links have attracted much more attention and have come to constitute a key market segment due to the rapid development of data-center applications and cloud services. Four-level pulse amplitude modulation (PAM4) is a promising modulation format to provide both a high data rate and relatively low cost for short-reach optical links. However, the direct detector and low-cost components also pose immense challenges, which are unforeseen in coherent transmission. To compensate for the impairments and to truly meet data rate requirements in a cost-effective manner, various digital signal processing (DSP) technologies have been proposed and investigated for short-reach PAM4 optical links. In this paper, an overview of the latest progress on DSP equalization technologies is provided for short-reach optical links based on PAM4 modulation. We not only introduce the configuration and challenges of the transmission system, but also cover the principles and performance of different equalizers and some improved methods. Moreover, machine learning algorithms are discussed as well to mitigate the nonlinear distortion for next-generation short-reach PAM4 links. Finally, a summary of various equalization technologies is illustrated and our perspective for the future trend is given.

Ultrahigh-speed Optical Communications Technology Combining Digital Signal Processing and Circuit Technology

Ultrahigh-speed Optical Communications Technology Combining Digital Signal Processing and Circuit Technology

CCi-MOBILE: Design and Evaluation of a Cochlear Implant and Hearing Aid Research Platform for Speech Scientists and Engineers.

Hearing loss is an increasingly prevalent condition resulting from damage to the inner ear which causes a reduction in speech intelligibility. The societal need for assistive hearing devices has increased exponentially over the past two decades; however, actual human performance with such devices has only seen modest gains relative to advancements in digital signal processing (DSP) technology. A major challenge with clinical hearing technologies is the limited ability to run complex signal processing algorithms requiring high computation power. The CCi-MOBILE platform, developed at UT-Dallas, provides the research community with an open-source, flexible, easy-to-use, software-mediated, powerful computing research interface to conduct a wide variety of listening experiments. The platform supports cochlear implants (CIs) and hearing aids (HAs) independently, as well as bimodal hearing (i.e., a CI in one ear and HA in the contralateral ear). The platform is ideally suited to address hearing research for: both quiet and naturalistic noisy conditions, sound localization, and lateralization. The platform uses commercially available smartphone/tablet devices as portable sound processors and can provide bilateral electric and acoustic stimulation. The hardware components, firmware, and software suite are presented to demonstrate safety to the speech scientist and CI/HA user, highlight user-specificity, and outline various applications of the platform for research.

Application of DBF in 77GHz Automotive Millimeter-wave Radar

The launch of unmanned models and the introduction of laws and regulations will promote the development of the autopilot industry. The greatest characteristic of millimeter-wave radar is its strong penetration, which can be used in harsh conditions such as rain, snow and heavy fog. It is an indispensable feature for future autopilot. According to the radar band, millimeter-wave radar is divided into 24GHz millimeter-wave radar and 77GHz millimeter-wave radar. 77GHz millimeter-wave radars will be the future development direction due to its farther detection range. Digital Beamforming (DBF) is a new technology that combines the principle of antenna beam forming with digital signal processing technology. At present, DBF is widely used in automotive 77GHz millimeter-wave radar. In this paper, the basic principle of DBF was explained firstly and then the method of amplitude and phase calibration of DBF weight coefficient in engineering was described. Finally the static and dynamic detection effects of automobile millimeter-wave radar based on DBF technology were given.

Advanced technology of high-resolution radar: target detection, tracking, imaging, and recognition

In recent years, the performances of radar resolution, coverage, and detection accuracy have been significantly improved through the use of ultra-wideband, synthetic aperture and digital signal processing technologies. High-resolution radars (HRRs) utilize wideband signals and synthetic apertures to enhance the range and angular resolutions of tracking, respectively. They also generate one-, two-, and even three-dimensional high-resolution images containing the feature information of targets, from which the targets can be precisely classified and identified. Advanced signal processing algorithms in HRRs obtain important information such as range-Doppler imaging, phase-derived ranging, and micro-motion features. However, the advantages and applications of HRRs are restricted by factors such as the reduced signal-to-noise ratio (SNR) of multi-scatter point targets, decreased tracking accuracy of multi-scatter point targets, high demands of motion compensation, and low sensitivity of the target attitude. Focusing on these problems, this paper systematically introduces the novel technologies of HRRs and discusses the issues and solutions relevant to detection, tracking, imaging, and recognition. Finally, it reviews the latest progress and representative results of HRR-based research, and suggests the future development of HRRs.

Research and Design of Rod Control Cabinet in Nuclear Power Plants Based on Digital Control

There are disadvantages such as poor applicability, slow dynamic response of load output and poor anti-interference ability of the rod control power supply cabinet in operation. This paper redesigns a new type of power cabinet based on programmable logic controller (PLC) and digital signal processing (DSP) technology which adopts fast energy absorption loop and double closed-loop control method in the main circuit. Then the coordination test in the cold and hot states between the designed cabinet and ACP1000 control rod drive mechanism(CRDM) is carried out. The test result proves that the function of the cabinet satisfies the application requirements of generation-III nuclear plants and effectively solves the disadvantages of the existing cabinet.