Digital Signal Processing Technology Research Articles

Robustness of Optical Steganographic Communication Under Coherent Detection Attack

In fiber-optic networks, optical steganographic communication hides the existence of stealth signals in public channels. The previous security analyses assumed threat models in which eavesdroppers rely only on the real-time key search in the optical domain for signal recovery. In this letter, we study a new threat model that uses coherent detection and offline digital signal processing (DSP) to recover the stealth signal, and we show the robustness of optical steganographic communication under this attack. We find that eavesdroppers equipped with the state-of-the-art coherent detectors and DSP technologies fail to estimate the secret key. In addition, even if the eavesdroppers are given the secret key, the stealth signal cannot be recovered from the signal using DSP. The histogram of the received signal after DSP displays a noise-like form which prevents eavesdroppers from detecting the existence of the stealth signal. We attribute the system robustness to the unique features of using amplified spontaneous emission noise as the signal carrier, including wide bandwidth, large phase variance, and fast phase fluctuation.

数字信号处理技术的发展与思考

数字信号处理技术的发展与思考

Advanced Digital Signal Processing for Reach Extension and Performance Enhancement of 112 Gbps and Beyond Direct Detected DML-Based Transmission

112 Gbps per wavelength, amplification free Four-level Pulse Amplitude Modulation (PAM-4) transmissions are experimentally demonstrated with advanced digital signal processing (DSP) algorithms. Two DSP architectures are investigated for Directly Modulated Lasers (DMLs): 1) the regular DSP with Feed Forward Equalization (FFE) and Decision Feedback Equalization (DFE), and 2) the enhanced DSP with Maximum Likelihood Sequence Estimation (MLSE) equalizer. The experimental results show that with advanced DSP technologies the conventional DML can achieve 40 km transmissions with Bit Error Rate (BER) under 2.4 × 10−4 that meets RS (544, 514) Forward Error Correction (FEC) requirement; with regular-DSP the advanced DML can achieve 40 km transmissions with BER under 3.8 × 10−3, with stronger FEC. 112 Gbps and beyond per lambda DML based transmission is a promising low power, low-cost solution for 800 GbE or 1.6 TbE Ethernet.

Coherent Receiver DSP Implemented on a General-Purpose Server for a Full Software-Defined Access System

To accommodate the service paradigm shift driven by the now amazingly wide variety of services, telecom operators must overcome many challenges in redesigning their network infrastructure to attain system flexibility, scalability, and cost effectiveness. A key part of the solution is the recent advent of network virtualization based on commodity hardware. We propose a unique edge-server architecture that combines network virtualiza- tion with advanced digital signal processing (DSP) technology. Our architecture has the server's central processing unit running application layer functions and a generalpurpose accelerator running dissimilar physical layer functions, including advanced DSP. To elucidate the power budget capability of our coherent detection scheme, a hardware experiment demonstrates the optical power budget of 45.2 dB for quadrature phase-shift keying signals of 5 Gbit/s bit rate.

Hidden Coexisting Attractors in a Chaotic System Without Equilibrium Point

This paper proposes a new three-dimensional chaotic system with no equilibrium point but can generate hidden chaotic attractors. Dynamic characteristics of the system are analyzed in detail by theoretical analysis and simulating experiments, including hidden attractors, transient period and coexisting attractors. Different hidden coexisting attractors exist in this system, which shows abundant and complex dynamic characteristics and can be used to generate pseudorandom sequences for encryption fields. Besides, the presented system is realized by the digital signal processing (DSP) technology to construct a chaotic signal generator, whose statistical properties are tested by National Institute of Standards and Technology (NIST) software. The obtained results are better than that of the Lorenz system and imply the presented system can be used in the encrypted fields.

The Effects of Hearing Aid Digital Noise Reduction and Directionality on Acceptable Noise Level.

Objectives Two main digital signal processing technologies inside the modern hearing aid to provide the best conditions for hearing aid users are directionality (DIR) and digital noise reduction (DNR) algorithms. There are various possible settings for these algorithms. The present study evaluates the effects of various DIR and DNR conditions (both separately and in combination) on listening comfort among hearing aid users.Methods In 18 participants who received hearing aid fitting services from the Rehabilitation School of Shahid Beheshti University of Medical Sciences regularly, we applied acceptable noise level (ANL) as our subjective measure of listening comfort. We evaluated both of these under six different hearing aid conditions: omnidirectional-baseline, omnidirectional-broadband DNR, omnidirectional-multichannel DNR, directional, directional-broadband DNR, and directional-multichannel DNR.Results The ANL results ranged from −3 dB to 14 dB in all conditions. The results show, among all conditions, both the omnidirectional-baseline condition and the omnidirectional-broadband DNR condition are the worst conditions for listening in noise. The DIR always reduces the amount of noise that patients received during testing. The DNR algorithm does not improve listening in noise significantly when compared with the DIR algorithms. Although both DNR and DIR algorithms yielded a lower ANL, the DIR algorithm was more effective than the DNR.Conclusion The DIR and DNR technologies provide listening comfort in the presence of noise. Thus, user benefit depends on how the digital signal processing settings inside the hearing aid are adjusted.

Application of Smart Antenna in TD - SCDMA

With the rapid development of global communications business, future personal communication wireless mobile communicationtechnology has aroused great concern. Way to eliminate the impact of co-channel interference (CCI), multiple access interference (MAI)and multipath fading becomes a major factor in improving the performance of wireless mobile communication systems. The smart antennauses the digital signal processing technology to generate the spatial directional beam so that the antenna main beam is aligned with thedirection of arrival of the user signal. The side lobe or the zero point is aligned to the direction of the interfering signal to reach the fullefficient use of the mobile subscriber signal, thus remove or suppress the interference signal purpose. Compared with other increasinglydeep and mature interference removal technology, the application of smart antenna technology in mobile communication is even more in theascendant and showing great potential. One of the key technologies of the third generation mobile communication standard TD-SCDMAsystem submitted by our country is the intelligent antenna technology. The paper introduces the history and development of the smartantenna in detail, and deeply analyzes the application of the smart antenna in TD-SCDMA. The application of smart antenna has beendeveloped.

Toward Transport Ecosystem Interoperability Enabled by Vendor-Diverse Coherent Optical Sources Over an Open Line System

Optical line-side interoperability is a critical component for enabling cloud service providers to deploy capacity at scale with a diverse supply chain. Historically, vendor-locked line systems and proprietary coherent digital signal processing (DSP) technologies have been barriers to this goal. Advances in open line platforms and coherent interfaces embedded directly in layer-2/3 switches and routers have begun paving the way toward full end-to-end interoperation. In this paper, we take a partial step toward demonstrating end-to-end interop by interoperating vendor-diverse packet switching platforms from Arista, Cisco, and Juniper, which utilize the same coherent DSP chip set, over an open line system (OLS). All three vendors' switches feature integrated coherent optics and are shown to interoperate over 2000 km at 150G 8QAM and 1000 km at 200G 16QAM on Microsoft's OLS.

Filtering Input Data of Neural Network Using Digital Signal Processing Technology

Одним из важных направлений исследования в области искусственного интеллекта можно назвать методы оптимизации, в том числе стохастические алгоритмы. Данная технология используется для решения различных задач во многих областях деятельности. Целью приведенного в статье исследования является улучшение обучения нейронной сети методом генетического алгоритма путем фильтрации входных данных с использованием технологии цифровой обработки сигналов. В качестве входных данных взяты биржевые котировки. Нейронная сеть представляет собой совокупность слоев нейронов, где каждый нейрон является функцией от суммы входных сигналов, умноженных на коэффициенты. В данной статье используется сигмовидная передаточная функция. Для улучшения качества обучения входные данные подвергаются фильтрации. В обзорной части рассмотрен технический анализ, метод автоматической регрессии и применение нейронных сетей. Выдвинута и проверена гипотеза возможности улучшения качества обучения нейронной сети за счет подавления шума в исходных данных с использованием методов ЦОС. Проверена гипотеза зависимости качества обучения нейронной сети от статистических характеристик выборки. Рассмотрен метод фильтрации биржевых котировок с использованием скользящей средней и медианной фильтрации. Приведены результаты эксперимента и численная оценка качества обучения, а также статистических характеристик выборки, тем самым подтверждена зависимость между статистическими характеристиками выборки и качеством обучения нейронной сети. Подтверждено положительное влияние предварительной фильтрации данных на качество обучения нейронной сети.

Encoding and decoding by the states of vector modes for vortex beams propagating in air-core fiber

In order to enhance the channel capacity and spectrum efficiency, the technology of space division multiplexing (SDM) has become research hotspot in optical communications. In this paper, a new encoding/decoding concept is proposed by the states of vector modes (polarized direction, rotational direction of phase and topological charge) for vortex beam propagating. To support encoded vector modes propagating in fiber, an OAM fiber with air-core structure is designed for encoding/decoding. Meanwhile, a new mode recognition method of judging states of the received vector modes is presented by the technology of digital image processing and digital signal processing (DSP). To verify the feasibility of encoding/decoding, an experimental platform to verify that encoded 16-QAM signal (0010_1100_1110_1010) is established. The vector modes of OAM beams can be propagated in OAM fiber with the length of 80 cm, and the received signal can be decoded to 16-QAM by image processing successfully. In addition, we also evaluate and analyze the influence factor (OAM fiber length and bit rate) on the transmitting performance in terms of BER, crosstalk and constellation figures.

Chaotic oscillator containing memcapacitor and meminductor and its dimensionality reduction analysis.

In this paper, smooth curve models of meminductor and memcapacitor are designed, which are generalized from a memristor. Based on these models, a new five-dimensional chaotic oscillator that contains a meminductor and memcapacitor is proposed. By dimensionality reducing, this five-dimensional system can be transformed into a three-dimensional system. The main work of this paper is to give the comparisons between the five-dimensional system and its dimensionality reduction model. To investigate dynamics behaviors of the two systems, equilibrium points and stabilities are analyzed. And the bifurcation diagrams and Lyapunov exponent spectrums are used to explore their properties. In addition, digital signal processing technologies are used to realize this chaotic oscillator, and chaotic sequences are generated by the experimental device, which can be used in encryption applications.

A study on iterative learning control for vibration of Stewart platform

This paper presents the replication of a desired vibration response by iterative learning control system for a Stewart platform. The Stewart platform is a multi-input, multi-output system with parameter uncertainties including system nonlinearity and joint nonlinearity. Most vehicle manufacturers are relying on road test simulation facilities in order to reduce development time and to enhance product quality. Road simulation algorithm is essential for developing road test simulation system. With digital signal processing technology, more complex control algorithms including iterative learning control can be utilized. In this paper, a controller based on iterative learning control (ILC) algorithm was developed to produce the desired target response in case of a single actuator as the first experiment after programmed with C language. As a next experiment, the control algorithm was implemented in a road test simulation system using a Stewart platform. A real test was carried out to replicate total six channels of acceleration signals measured at top and left side points of audio player system installed to a car running on Belgian road. The convergence rate and test simulation accuracy higher than 90% showed that the algorithm was acceptable to replicate the target vibration response.

A novel power efficient 0.64-GFlops fused 32-bit reversible floating point arithmetic unit architecture for digital signal processing applications

Floating point digital signal processing technology has become the primary method for real time signal processing in most digital systems presently. However, the challenges in the implementation of floating point arithmetic on FPGA are that, the hardware modules are larger, have longer latency and high power consumption. In this work, a novel efficient reversible floating point fused arithmetic unit architecture is proposed confirming to IEEE 754 standard. By utilizing reversible logic circuits and implementation with adiabatic logic, power efficiency is achieved. The hardware complexity is reduced by employing fused elements and latency is improved by decomposing the operands in the realization of floating point multiplier and square root. To validate the design, the proposed unit was used for realization of FFT and FIR filter which are important applications of a DSP processor. As detection is one of the core baseband processing operations in digital communication receivers and the detection speed determines the data rates that can be achieved, the proposed unit has been used to implement the detection function. Simulation results and comparative studies with existing works demonstrate that the proposed unit efficiently utilizes the number of gates, has reduced quantum cost and produced less garbage outputs with low latency, thereby making the design a computational and power efficient one.

基于DSP技术的外腔半导体激光器自动稳频系统

基于DSP技术的外腔半导体激光器自动稳频系统

Shortwave spatial spectrum direction finding and positioning system based on software communication architecture

With the rapid advances in digital signal processing technology, spatial spectrum estimation theory and technology has been widely used in various fields and has become a new favorite in radio direction finding and passive positioning fields. This paper constructs a new shortwave spatial spectrum direction finding and positioning system, which establishes a standard interoperable platform based on software communication architecture (SCA). Meanwhile, a new shortwave co-location method is put forward, which realizes the flexible networking of the new shortwave spatial spectral direction finding system through the optical fiber or Ethernet. Besides, cyclic direction of arrival (DOA) estimation and weighted average method are applied to improve the positioning accuracy under complex environments. Simulation results show that this method has good positioning performance and stability.

Image Acquisition Method Based on TMS320DM642

In order to achieve high-speed, real-time and accurate, an image acquisition method based on digital signal processor (DSP) TMS320DM642 is proposed for the paper currency image acquisition [1]. System will be high speed digital signal processing (DSP) technology and complex programmable logic device (CPLD) and CIS acquisition module combination, the structure of acquisition system is given and the time series analysis, during the process of collecting this kind of design has the advantages of simple implementation, high recognition rate [2].

The Design and Implementation of a New Type of Track Test Plate

Due to the low efficiency and precision of the traditional way of orbit test plate measuring, a new type of track test plate based on digital signal processing technology was designed. For the 48 track circuits, a modular designment method was proposed to simplify assembly and maintenance; The rail voltage and the local voltage input circuits were designed, so that the signal can be directly obtained by MCU; According to the characteristics of 25 Hz circuit, Fourier series method was selected, which can extract separate extraction under the condition of higher harmonic fundamental component. And the uniformity calibration was used to improve the precision and reduce error. The track plate was tested by the simulation of railway signal, the rail voltage and the local voltage error is less than or equal to ±1%, and the phase angle measurement error is less than or equal to ± 0.5°. Measurement speed goes up to once per second when 48 roads are measured in the same time. The experimental results show that the system measuring accuracy is higher, faster, and has a great practical value.

Applications of convolution to intravenous anesthetics

Modern medicine has made remarkable progress with engineering. Computed tomography is a diagnostic tool that uses digitalsignal processing technology. Understanding the basic principles of medical devices that are widely used in modern medicineby clinicians can improve the accuracy of care and patient safety.Intravenous anesthetic agents induce respiratory depression and cardiovascular complications, so its administration requiresprofessional training. Target controlled infusion (TCI) is a device developed to administer intravenous anesthetics relativelysafely. This device is a device that applies the pharmacokinetic / pharmacokinetic principle.This paper reviews the literature on pharmacokinetic concepts and applications of convolution for administration ofintravenous anesthetics.

A new generation scanning system for the high-speed analysis of nuclear emulsions

The development of automatic scanning systems was a fundamental issue for large scale neutrino detectors exploiting nuclear emulsions as particle trackers. Such systems speed up significantly the event analysis in emulsion, allowing the feasibility of experiments with unprecedented statistics. In the early 1990s, R&D programs were carried out by Japanese and European laboratories leading to automatic scanning systems more and more efficient. The recent progress in the technology of digital signal processing and of image acquisition allows the fulfillment of new systems with higher performances. In this paper we report the description and the performance of a new generation scanning system able to operate at the record speed of 84 cm2/hour and based on the Large Angle Scanning System for OPERA (LASSO) software infrastructure developed by the Naples scanning group. Such improvement, reduces the scanning time by a factor 4 with respect to the available systems, allowing the readout of huge amount of nuclear emulsions in reasonable time. This opens new perspectives for the employment of such detectors in a wider variety of applications.

Correction of Microplate Data from High-Throughput Screening.

High-throughput screening (HTS) makes it possible to collect cellular response data from a large number of cell lines and small molecules in a timely and cost-effective manner. The errors and noises in the microplate-formatted data from HTS have unique characteristics, and they can be generally grouped into three categories: run-wise (temporal, multiple plates), plate-wise (background pattern, single plate), and well-wise (single well). In this chapter, we describe a systematic solution for identifying and correcting such errors and noises, mainly basing on pattern recognition and digital signal processing technologies.